Merge branch 'feature/eglot2emacs'

4 files changed, 4588 insertions, 1 deletions

diff --git a/doc/misc/Makefile.in b/doc/misc/Makefile.in
index 1d881a5fc7f..b6eef7ea799 100644
--- a/doc/misc/Makefile.in
+++ b/doc/misc/Makefile.in
@@ -68,7 +68,7 @@ DOCMISC_W32 = @DOCMISC_W32@
 
 ## Info files to build and install on all platforms.
 INFO_COMMON = auth autotype bovine calc ccmode cl \
-        dbus dired-x ebrowse ede ediff edt eieio \
+        dbus dired-x ebrowse ede ediff edt eglot eieio \
         emacs-mime epa erc ert eshell eudc efaq eww \
         flymake forms gnus emacs-gnutls htmlfontify idlwave ido info.info \
         mairix-el message mh-e modus-themes newsticker nxml-mode octave-mode \
diff --git a/doc/misc/eglot.texi b/doc/misc/eglot.texi
new file mode 100644
index 00000000000..6a4127bed7c
--- /dev/null
+++ b/doc/misc/eglot.texi
@@ -0,0 +1,1129 @@
+\input texinfo  @c -*-texinfo-*-
+@c %**start of header
+@setfilename ../../eglot.info
+@settitle Eglot: The Emacs Client for the Language Server Protocol
+@include docstyle.texi
+@syncodeindex vr cp
+@syncodeindex fn cp
+@c %**end of header
+
+@copying
+This manual is for Eglot, the Emacs LSP client.
+
+Copyright @copyright{} 2022 Free Software Foundation, Inc.
+
+@quotation
+Permission is granted to copy, distribute and/or modify this document
+under the terms of the GNU Free Documentation License, Version 1.3 or
+any later version published by the Free Software Foundation; with no
+Invariant Sections, with the Front-Cover Texts being ``A GNU Manual'',
+and with the Back-Cover Texts as in (a) below.  A copy of the license
+is included in the section entitled ``GNU Free Documentation License''.
+
+(a) The FSF's Back-Cover Text is: ``You have the freedom to copy and
+modify this GNU manual.''
+@end quotation
+@end copying
+
+@dircategory Emacs misc features
+@direntry
+* Eglot: (eglot).             Language Server Protocol client for Emacs.
+@end direntry
+
+@titlepage
+@sp 4
+@c The title is printed in a large font.
+@center @titlefont{User's Guide}
+@sp 1
+@center @titlefont{to}
+@sp 1
+@center @titlefont{Eglot: The Emacs LSP Client}
+@ignore
+@sp 2
+@center release 1.8
+@c -release-
+@end ignore
+@sp 3
+@center Jo@~ao T@'avora & Eli Zaretskii
+@c -date-
+
+@page
+@vskip 0pt plus 1filll
+@insertcopying
+@end titlepage
+
+@contents
+
+@ifnottex
+@node Top
+@top Eglot
+
+@cindex LSP
+@cindex language server protocol
+Eglot is the Emacs client for the @dfn{Language Server Protocol}
+(@acronym{LSP}).  The name ``Eglot'' is an acronym that stands for
+``@emph{E}macs Poly@emph{glot}''.@footnote{
+A @dfn{polyglot} is a
+person who is able to use several languages.
+} Eglot provides infrastructure and a set of commands for enriching
+the source code editing capabilities of Emacs via LSP.  LSP is a
+standardized communications protocol between source code editors (such
+as Emacs) and language servers, programs external to Emacs for
+analyzing source code on behalf of Emacs.  The protocol allows Emacs
+to receive various source code services from the server, such as
+description and location of functions calls, types of variables, class
+definitions, syntactic errors, etc.  This way, Emacs doesn't need to
+implement the language-specific parsing and analysis capabilities in
+its own code, but is still capable of providing sophisticated editing
+features that rely on such capabilities, such as automatic code
+completion, go-to definition of function/class, documentation of
+symbol at-point, refactoring, on-the-fly diagnostics, and more.
+
+Eglot itself is completely language-agnostic, but it can support any
+programming language for which there is a language server and an Emacs
+major mode.
+
+This manual documents how to configure, use, and customize Eglot.
+
+@insertcopying
+
+@menu
+* Quick Start::                 For the impatient.
+* Eglot and LSP Servers::       How to work with language servers.
+* Using Eglot::                 Important Eglot commands and variables.
+* Customizing Eglot::           Eglot customization and advanced features.
+* Troubleshooting Eglot::       Troubleshooting and reporting bugs.
+* GNU Free Documentation License::  The license for this manual.
+* Index::
+@end menu
+@end ifnottex
+
+@node Quick Start
+@chapter Quick Start
+@cindex quick start
+
+This chapter provides concise instructions for setting up and using
+Eglot with your programming project in common usage scenarios.  For
+more detailed instructions regarding Eglot setup, @pxref{Eglot and LSP
+Servers}.  @xref{Using Eglot}, for detailed description of using Eglot,
+and see @ref{Customizing Eglot}, for adapting Eglot to less common use
+patterns.
+
+Here's how to start using Eglot with your programming project:
+
+@enumerate
+@item
+Select and install a language server.
+
+Eglot comes pre-configured with many popular language servers, see the
+value of @code{eglot-server-programs}.  If the server(s) mentioned
+there satisfy your needs for the programming language(s) with which
+you want to use Eglot, you just need to make sure those servers are
+installed on your system.  Alternatively, install one or more servers
+of your choice and add them to the value of
+@code{eglot-server-programs}, as described in @ref{Setting Up LSP
+Servers}.
+
+@item
+Turn on Eglot for your project.
+
+To start using Eglot for a project, type @kbd{M-x eglot @key{RET}} in
+a buffer visiting any file that belongs to the project.  This starts
+the language server configured for the programming language of that
+buffer, and causes Eglot to start managing all the files of the
+project which use the same programming language.  The notion of a
+``project'' used by Eglot is the same Emacs uses (@pxref{Projects,,,
+emacs, GNU Emacs Manual}): in the simplest case, the ``project'' is
+the single file you are editing, but it can also be all the files in a
+single directory or a directory tree under some version control
+system, such as Git.
+
+Alternatively, you can start Eglot automatically from the major-mode
+hook of the mode used for the programming language; see @ref{Starting
+Eglot}.
+
+@item
+Use Eglot.
+
+Most Eglot facilities are integrated into Emacs features, such as
+ElDoc, Flymake, Xref, and Imenu.  However, Eglot also provides
+commands of its own, mainly to perform tasks by the LSP server, such
+as @kbd{M-x eglot-rename} (to rename an identifier across the entire
+project), @kbd{M-x eglot-format} (to reformat and reindent code), and
+some others.  @xref{Eglot Commands}, for the detailed list of Eglot
+commands.
+
+@item
+That's it!
+@end enumerate
+
+@node Eglot and LSP Servers
+@chapter Eglot and LSP Servers
+
+This chapter describes how to set up Eglot for your needs, and how to
+start it.
+
+@menu
+* Setting Up LSP Servers::   How to configure LSP servers for your needs.
+* Starting Eglot::              Ways of starting Eglot for your project.
+* Shutting Down LSP Servers::
+@end menu
+
+@node Setting Up LSP Servers
+@section Setting Up LSP Servers
+@cindex setting up LSP server for Eglot
+@cindex language server for Eglot
+
+For Eglot to be useful, it must first be combined with a suitable
+language server.  Usually, that means running the server program
+locally as a child process of Emacs (@pxref{Processes,,, elisp, GNU
+Emacs Lisp Reference Manual}) and communicating with it via the
+standard input and output streams.
+
+The language server program must be installed separately, and is not
+further discussed in this manual; refer to the documentation of the
+particular server(s) you want to install.
+
+To use a language server, Eglot must know how to start it and which
+programming languages each server supports.  Eglot comes with a fairly
+complete set of associations of major-modes to popular language
+servers predefined.  This information is provided by the
+@code{eglot-server-programs} variable.
+
+@defvar eglot-server-programs
+This variable associates major modes with names and command-line
+arguments of the language server programs corresponding to the
+programming language of each major mode.  It provides all the
+information that Eglot needs to know about the programming language of
+the source you are editing.
+
+The value of the variable is an alist, whose elements are of the form
+@w{@code{(@var{major-mode} . @var{server})}}.
+
+The @var{major-mode} of the alist elements can be either a symbol of
+an Emacs major mode or a list of the form @w{@code{(@var{mode}
+:language-id @var{id})}}, with @var{mode} being a major-mode symbol
+and @var{id} a string that identifies the language to the server.  The
+latter form should be used if Eglot cannot by itself convert the
+major-mode to the language identifier string required by the server.
+In addition, @var{major-mode} can be a list of several major modes
+specified in one of the above forms -- this means a running instance
+of the associated server is responsible for files of multiple major
+modes or languages in the project.
+
+The @var{server} part of the alist elements can be one of the
+following:
+
+@table @code
+@item (@var{program} @var{args}@dots{})
+This says to invoke @var{program} with zero or more arguments
+@var{args}; the program is expected to communicate with Emacs via the
+standard input and standard output streams.
+
+@item (@var{program} @var{args}@dots{} :initializationOptions @var{options}@dots{})
+Like above, but with @var{options} specifying the options to be
+used for constructing the @samp{initializationOptions} JSON object for
+the server.  @var{options} can also be a function of one argument, in
+which case it will be called with the server instance as the argument,
+and should return the JSON object to use for initialization.
+
+@item (@var{host} @var{port} @var{args}@dots{})
+Here @var{host} is a string and @var{port} is a positive integer
+specifying a TCP connection to a remote server.  The @var{args} are
+passed to @code{open-network-stream}, e.g.@: if the connection needs
+to use encryption or other non-default parameters (@pxref{Network,,,
+elisp, GNU Emacs Lisp Reference Manual}).
+
+@item (@var{program} @var{args}@dots{} :autoport @var{moreargs}@dots{})
+@var{program} is started with a command line constructed from
+@var{args} followed by an available server port and the rest of
+arguments in @var{moreargs}; Eglot then establishes a TCP connection
+with the server via that port on the local host.
+
+@item @var{function}
+This should be a function of a single argument: non-@code{nil} if the
+connection was requested interactively (e.g., by the @code{eglot}
+command), otherwise @code{nil}.  The function should return a value of
+any of the forms described above.  This allows interaction with the
+user for determining the program to start and its command-line
+arguments.
+@end table
+
+@end defvar
+
+If you need to add server associations to the default list, use
+@code{add-to-list}.  For example, if there is a hypothetical language
+server program @command{fools} for the language @code{Foo} which is
+supported by an Emacs major-mode @code{foo-mode}, you can add it to
+the alist like this:
+
+@lisp
+(add-to-list 'eglot-server-programs
+             '(foo-mode . ("fools" "--stdio")))
+@end lisp
+
+This will invoke the program @command{fools} with the command-line
+argument @option{--stdio} in support of editing source files for which
+Emacs turns on @code{foo-mode}, and will communicate with the program
+via the standard streams.  As usual with invoking programs, the
+executable file @file{fools} should be in one of the directories
+mentioned by the @code{exec-path} variable (@pxref{Subprocess
+Creation,,, elisp, GNU Emacs Lisp Reference Manual}), for Eglot to be
+able to find it.
+
+@node Starting Eglot
+@section Starting Eglot
+@cindex starting Eglot
+@cindex activating Eglot for a project
+
+@findex eglot
+The most common way to start Eglot is to simply visit a source file of
+a given language and use the command @kbd{M-x eglot}.  This starts the
+language server suitable for the visited file's major-mode, and
+attempts to connect to it.  If the connection to the language server
+is successful, you will see the @code{[eglot:@var{project}]} indicator
+on the mode line which reflects the server that was started.  If the
+server program couldn't be started or connection to it failed, you
+will see an error message; in that case, try to troubleshoot the
+problem as described in @ref{Troubleshooting Eglot}.  Once a language
+server was successfully started and Eglot connected to it, you can
+immediately start using the Emacs features supported by Eglot, as
+described in @ref{Eglot Features}.
+
+A single Eglot session for a certain major-mode usually serves all the
+buffers under that mode which visit files from the same project, so
+you don't need to invoke @kbd{M-x eglot} again when you visit another
+file from the same project which is edited using the same major-mode.
+This is because Eglot uses the Emacs project infrastructure, as
+described in @ref{Eglot and Buffers}, and this knows about files that
+belong to the same project.  Thus, after starting an Eglot session for
+some buffer, that session is automatically reused when visiting files
+in the same project with the same major-mode.
+
+@findex eglot-ensure
+Alternatively, you could configure Eglot to start automatically for
+one or more major-modes from the respective mode hooks.  Here's an
+example for a hypothetical @code{foo-mode}:
+
+@lisp
+ (add-hook 'foo-mode-hook 'eglot-ensure)
+@end lisp
+
+@noindent
+The function @code{eglot-ensure} will start an Eglot session for each
+buffer in which @code{foo-mode} is turned on, if there isn't already
+an Eglot session that handles the buffer.  Note that this variant of
+starting an Eglot session is non-interactive, so it should be used
+only when you are confident that Eglot can be started reliably for any
+file which may be visited with the major-mode in question.
+
+When Eglot connects to a language server for the first time in an
+Emacs session, it runs the hook @code{eglot-connect-hook}
+(@pxref{Eglot Variables}).
+
+@node Shutting Down LSP Servers
+@section Shutting Down LSP Servers
+@cindex shutting down LSP server
+
+When Eglot is turned on, it arranges for turning itself off
+automatically if the language server process terminates.  Turning off
+Eglot means that it shuts down the server connection, ceases its
+management of all the buffers that use the server connection which was
+terminated, deactivates its minor mode, and restores the original
+values of the Emacs variables that Eglot changed when it was turned
+on.  @xref{Eglot and Buffers}, for more details of what Eglot
+management of a buffer entails.
+
+@findex eglot-shutdown
+You can also shut down a language server manually, by using the
+command @kbd{M-x eglot-shutdown}.  This prompts for the server (unless
+there's only one connection and it's used in the current buffer), and
+then shuts it down.  By default, it also kills the server's events
+buffer (@pxref{Troubleshooting Eglot}), but a prefix argument prevents
+that.
+
+Alternatively, you can customize the variable
+@code{eglot-autoshutdown} to a non-@code{nil} value, in which case
+Eglot will automatically shut down the language server process when
+the last buffer served by that language server is killed.  The default
+of this variable is @code{nil}, so that visiting another file would
+automatically activate Eglot even when the project which started Eglot
+with the server no longer has any buffer associated with it.  This
+default allows you to start a server only once in each Emacs session.
+
+@node Using Eglot
+@chapter Using Eglot
+
+This chapter describes in detail the features that Eglot provides and
+how it does that.  It also provides reference sections for Eglot
+commands and variables.
+
+@menu
+* Eglot Features::
+* Eglot and Buffers::
+* Eglot Commands::
+* Eglot Variables::
+@end menu
+
+@node Eglot Features
+@section Eglot Features
+@cindex features in buffers supported by Eglot
+
+Once Eglot is enabled in a buffer, it uses LSP and the language-server
+capabilities to activate, enable, and enhance modern IDE features in
+Emacs.  The features themselves are usually provided via other Emacs
+packages.  These are the main features that Eglot enables and provides:
+
+@itemize @bullet
+@item
+At-point documentation: when point is at or near a symbol or an
+identifier, the information about the symbol/identifier, such as the
+signature of a function or class method and server-generated
+diagnostics, is made available via the ElDoc package (@pxref{Lisp
+Doc,,, emacs, GNU Emacs Manual}).  This allows major modes to provide
+extensive help and documentation about the program identifiers.
+
+@item
+On-the-fly diagnostic annotations with server-suggested fixes, via the
+Flymake package (@pxref{Top,,, flymake, GNU Flymake manual}).  This
+improves and enhances the Flymake diagnostics, replacing the other
+Flymake backends.
+
+@item
+Finding definitions and uses of identifiers, via Xref (@pxref{Xref,,,
+emacs, GNU Emacs Manual}).  Eglot provides a backend for the Xref
+capabilities which uses the language-server understanding of the
+program source.  In particular, it eliminates the need to generate
+tags tables (@pxref{Tags tables,,, emacs, GNU Emacs Manual}) for
+languages that are only supported by the @code{etags} backend.
+
+@item
+Buffer navigation by name of function, class, method, etc., via Imenu
+(@pxref{Imenu,,, emacs, GNU Emacs Manual}).  Eglot provides its own
+variant of @code{imenu-create-index-function}, which generates the
+index for the buffer based on language-server program source analysis.
+
+@item
+Enhanced completion of symbol at point by the
+@code{completion-at-point} command (@pxref{Symbol Completion,,, emacs,
+GNU Emacs Manual}).  This uses the language-server's parser data for
+the completion candidates.
+
+@item
+Automatic reformatting of source code as you type it.  This is similar
+to what the @code{eglot-format} command does (see below), but is
+activated automatically as you type.
+
+@item
+If a completion package such as @code{company-mode}, a popular
+third-party completion package, is installed, Eglot enhances it by
+providing completion candidates based on the language-server analysis
+of the source code.  (@code{company-mode} can be installed from GNU ELPA.)
+
+@item
+If @code{yasnippet}, a popular third-party package for automatic
+insertion of code templates (snippets), is installed, and the language
+server supports snippet completion candidates, Eglot arranges for the
+completion package to instantiate these snippets using
+@code{yasnippet}.  (@code{yasnippet} can be installed from GNU ELPA.)
+
+@item
+If the popular third-party package @code{markdown-mode} is installed,
+and the server provides at-point documentation formatted as Markdown
+in addition to plain text, Eglot arranges for the ElDoc package to
+enrich this text with e.g. fontification before displaying it to the
+user.
+
+@item
+In addition to enabling and enhancing other features and packages,
+Eglot also provides a small number of user commands based directly on
+the capabilities of language servers.  These commands are:
+
+@table @kbd
+@item M-x eglot-rename
+This prompts for a new name for the symbol at point, and then modifies
+all the project source files to rename the symbol to the new name,
+based on editing data received from the language-server.  @xref{Eglot
+and Buffers}, for the details of how project files are defined.
+
+@item M-x eglot-format
+This reformats and prettifies the current active region according to
+source formatting rules of the language-server.  If the region is not
+active, it reformats the entire buffer instead.
+
+@item M-x eglot-format-buffer
+This reformats and prettifies the current buffer according to source
+formatting rules of the language-server.
+
+@cindex code actions
+@item M-x eglot-code-actions
+@itemx M-x eglot-code-action-organize-imports
+@itemx M-x eglot-code-action-quickfix
+@itemx M-x eglot-code-action-extract
+@itemx M-x eglot-code-action-inline
+@itemx M-x eglot-code-action-rewrite
+These command allow you to invoke the so-called @dfn{code actions}:
+requests for the language-server to provide editing commands for
+various code fixes, typically either to fix an error diagnostic or to
+beautify/refactor code.  For example,
+@code{eglot-code-action-organize-imports} rearranges the program
+@dfn{imports}---declarations of modules whose capabilities the program
+uses.  These commands affect all the files that belong to the
+project.  The command @kbd{M-x eglot-code-actions} will pop up a menu
+of code applicable actions at point.
+@end table
+
+@end itemize
+
+Not all servers support the full set of LSP capabilities, but most of
+them support enough to enable the basic set of features mentioned
+above.  Conversely, some servers offer capabilities for which no
+equivalent Emacs package exists yet, and so Eglot cannot (yet) expose
+these capabilities to Emacs users.
+
+@node Eglot and Buffers
+@section Buffers, Projects, and Eglot
+@cindex buffers managed by Eglot
+@cindex projects and Eglot
+
+@cindex workspace
+One of the main strong points of using a language server is that a
+language server has a broad view of the program: it considers more
+than just the single source file you are editing.  Ideally, the
+language server should know about all the source files of your program
+which are written in the language supported by the server.  In the
+language-server parlance, the set of the source files of a program is
+known as a @dfn{workspace}.  The Emacs equivalent of a workspace is a
+@dfn{project} (@pxref{Projects,,, emacs, GNU Emacs Manual}).  Eglot
+fully supports Emacs projects, and considers the file in whose buffer
+Eglot is turned on as belonging to a project.  In the simplest case,
+that file is the entire project, i.e.@: your project consists of a
+single file.  But there are other more complex projects:
+
+@itemize @bullet
+@item
+A single-directory project: several source files in a single common
+directory.
+
+@item
+A VC project: source files in a directory hierarchy under some VCS,
+e.g.@: a Git repository (@pxref{Version Control,,, emacs, GNU Emacs
+Manual}).
+
+@item
+An EDE project: source files in a directory hierarchy managed via the
+Emacs Development Environment (@pxref{EDE,,, emacs, GNU Emacs
+Manual}).
+@end itemize
+
+Eglot uses the Emacs's project management infrastructure to figure out
+which files and buffers belong to what project, so any kind of project
+supported by that infrastructure is automatically supported by Eglot.
+
+When Eglot starts a server program, it does so in the project's root
+directory, which is usually the top-level directory of the project's
+directory hierarchy.  This ensures the language server has the same
+comprehensive view of the project's files as you do.
+
+For example, if you visit the file @file{~/projects/fooey/lib/x.foo}
+and @file{x.foo} belongs to a project rooted at
+@file{~/projects/fooey} (perhaps because a @file{.git} directory
+exists there), then @kbd{M-x eglot} causes the server program to start
+with that root as the current working directory.  The server then will
+analyze not only the file @file{lib/x.foo} you visited, but likely
+also all the other @file{*.foo} files under the
+@file{~/projects/fooey} directory.
+
+In some cases, additional information specific to a given project will
+need to be provided to the language server when starting it.  The
+variable @code{eglot-workspace-configuration} (@pxref{Customizing
+Eglot}) exists for that purpose.  It specifies the parameters and
+their values to communicate to each language server which needs that.
+
+When Eglot is active for a project, it performs several background
+activities on behalf of the project and its buffers:
+
+@itemize @bullet
+@cindex mode-line indication of language server
+@cindex mouse clicks on mode-line, and Eglot
+@vindex eglot-menu
+@item
+All of the project's file-visiting buffers under the same major-mode
+are served by a single language-server connection.  (If the project
+uses several programming languages, there will usually be a separate
+server connection for each group of files written in the same language
+and using the same Emacs major-mode.)  Eglot adds the
+@samp{[eglot:@var{project}]} indication to the mode line of
+each such buffer, where @var{server} is the name of the server and
+@var{project} identifies the project by its root directory.  Clicking
+the mouse on the Eglot mode-line indication activates a menu with
+server-specific items.
+
+@item
+For each buffer in which Eglot is active, it notifies the language
+server that Eglot is @dfn{managing} the file visited by that buffer.
+This tells the language server that the file's contents on disk may no
+longer be up-to-date due to unsaved edits.  Eglot reports to the
+server any changes in the text of each managed buffer, to make the
+server aware of unsaved changes.  This includes your editing of the
+buffer and also changes done automatically by other Emacs features and
+commands.  Killing a buffer relinquishes its management by Eglot and
+notifies the server that the file on disk is up-to-date.
+
+@vindex eglot-managed-mode-hook
+@vindex eglot-managed-p
+@item
+Eglot turns on a special minor mode in each buffer it manages.  This
+minor mode ensures the server is notified about files Eglot manages,
+and also arranges for other Emacs features supported by Eglot
+(@pxref{Eglot Features}) to receive information from the language
+server, by changing the settings of these features.  Unlike other
+minor-modes, this special minor mode is not activated manually by the
+user, but automatically as result of starting an Eglot session for the
+buffer.  However, this minor mode provides a hook variable
+@code{eglot-managed-mode-hook} that can be used to customize the Eglot
+management of the buffer.  This hook is run both when the minor mode
+is turned on and when it's turned off; use the variable
+@code{eglot-managed-p} to tell if current buffer is still being
+managed or not.  When Eglot stops managing the buffer, this minor mode
+is turned off, and all the settings that Eglot changed are restored to
+their original values.
+
+@item
+When you visit a file under the same project, whether an existing or a
+new file, its buffer is automatically added to the set of buffers
+managed by Eglot, and the server which supports the buffer's
+major-mode is notified about that.  Thus, visiting a non-existent file
+@file{/home/joe/projects/fooey/lib/y.foo} in the above example will
+notify the server of the @file{*.foo} files' language that a new file
+was added to the project, even before the file appears on disk.  The
+special Eglot minor mode is also turned on automatically in the buffer
+visiting the file.
+@end itemize
+
+@node Eglot Commands
+@section Eglot Commands
+@cindex commands, Eglot
+
+This section provides a reference of the most commonly used Eglot
+commands:
+
+@ftable @code
+@item M-x eglot
+This command adds the current buffer and the file it visits to the
+group of buffers and files managed by Eglot on behalf of a suitable
+language server.  If a language server for the buffer's
+@code{major-mode} (@pxref{Major Modes,,, emacs, GNU Emacs Manual}) is
+not yet running, it will be started; otherwise the buffer and its file
+will be added to those managed by an existing server session.
+
+The command attempts to figure out the buffer's major mode and the
+suitable language server; in case it fails, it might prompt for the
+major mode to use and for the server program to start.  If invoked
+with a prefix argument @kbd{C-u}, it always prompts for the server
+program, and if invoked with @kbd{C-u C-u}, also prompt for the major
+mode.
+
+If the language server is successfully started and contacted, this
+command arranges for any other buffers belonging to the same project
+and using the same major mode to use the same language-server session.
+That includes any buffers created by visiting files after this command
+succeeds to connect to a language server.
+
+All the Emacs features that are capable of using Eglot services
+(@pxref{Eglot Features}) are automatically configured by this command
+to start using the language server via Eglot.  To customize which
+Emacs features will be configured to use Eglot, use the
+@code{eglot-stay-out-of} option (@pxref{Customizing Eglot}).
+
+@item M-x eglot-reconnect
+Shuts down an the current connection to the language server and
+immediately restarts it using the same options used originally.  This
+can sometimes be useful to unclog a partially malfunctioning server
+connection.
+
+@item M-x eglot-shutdown
+Shuts down a language server.  This commands prompts for a language
+server to shut down (unless there's only one server session, and it
+manages the current buffer).  Then the command shuts down the server
+and stops managing the buffers the server was used for.  Emacs
+features (@pxref{Eglot Features}) that Eglot configured to work with
+the language server are restored back to their original configuration.
+
+Normally, this command kills the buffers used for communicating with
+the language server, but if invoked with a prefix argument @kbd{C-u},
+the command doesn't kill those buffers, allowing them to be used for
+diagnostics and problem reporting (@pxref{Troubleshooting Eglot}).
+
+@item M-x eglot-shutdown-all
+This command shuts down all the language servers active in the current
+Emacs session.  As with @code{eglot-shutdown}, invoking this command
+with a prefix argument avoids killing the buffers used for
+communications with the language servers.
+
+@item M-x eglot-rename
+This command renames the program symbol (a.k.a.@: @dfn{identifier}) at
+point to another name.  It prompts for the new name of the symbol, and
+then modifies all the files in the project which arte managed by the
+language server of the current buffer to implement the renaming.
+
+@item M-x eglot-format
+This command reformats the active region according to the
+language-server rules.  If no region is active, it reformats the
+entire current buffer.
+
+@item M-x eglot-format-buffer
+This command reformats the current buffer, in the same manner as
+@code{eglot-format} does.
+
+@item M-x eglot-code-actions
+@itemx mouse-1
+This command asks the server for any @dfn{code actions} applicable at
+point.  It can also be invoked by @kbd{mouse-1} clicking on
+diagnostics provided by the server.
+
+@item M-x eglot-code-action-organize-imports
+@itemx M-x eglot-code-action-quickfix
+@itemx M-x eglot-code-action-extract
+@itemx M-x eglot-code-action-inline
+@itemx M-x eglot-code-action-rewrite
+These commands invoke specific code actions supported by the language
+server.
+@c FIXME: Need more detailed description of each action.
+@end ftable
+
+The following Eglot commands are used less commonly, mostly for
+diagnostic and troubleshooting purposes:
+
+@ftable @code
+@item M-x eglot-events-buffer
+This command pops up the events buffer used for communication with the
+language server of the current buffer.
+
+@item M-x eglot-stderr-buffer
+This command pops up the buffer with the debug info printed by the
+language server to its standard error stream.
+
+@item M-x eglot-forget-pending-continuations
+Forget pending requests for the server of the current buffer.
+@c FIXME: Better description of the need.
+
+@item M-x eglot-signal-didChangeConfiguration
+This command updates the language server configuration according to
+the current value of the variable @code{eglot-workspace-configuration}
+(@pxref{Customizing Eglot}).
+
+@item M-x eglot-clear-status
+Clear the last JSONRPC error for the server of the current buffer.
+Eglot keeps track of erroneous situations encountered by the server in
+its mode-line indication so that the user may inspect the
+communication leading up to it (@pxref{Troubleshooting Eglot}).  If
+the situation is deemed uninteresting or temporary, this command can
+be used to ``forget'' the error.  Note that the command @code{M-x
+eglot-reconnect} can sometimes be used to unclog a temporarily
+malfunctioning server.
+@end ftable
+
+As described in @ref{Eglot Features} most features associated with
+Eglot are actually provided by other Emacs packages and features, and
+Eglot only enhances them by allowing them to use the information
+coming from the language servers.  For completeness, here's the list
+of commands of those other packages that are very commonly used in
+Eglot-managed buffers:
+
+@c Not @ftable, because the index entries should mention Eglot
+@table @code
+@cindex eldoc, and Eglot
+@cindex documentation using Eglot
+@item M-x eldoc
+Ask the ElDoc system for help at point.
+
+@cindex flymake, and Eglot
+@cindex on-the-fly diagnostics using Eglot
+@item M-x flymake-show-buffer-diagnostics
+Ask Flymake system to display diagnostics for the current buffer.
+
+@item M-x flymake-show-project-diagnostics
+Ask Flymake to list diagnostics for all the files in the current
+project.
+
+@cindex xref, and Eglot
+@cindex finding definitions of identifiers using Eglot
+@item M-x xref-find-definitions
+Ask Xref to go the definition of the identifier at point.
+
+@cindex imenu navigation using Eglot
+@item M-x imenu
+Let the user navigate the program source code using buffer index,
+categorizing program elements by syntactic class (class, method,
+variable, etc.) and offering completion.
+
+@cindex symbol completion using Eglot
+@item M-x completion-at-point
+Request completion of the symbol at point.
+@end table
+
+@node Eglot Variables
+@section Eglot Variables
+@cindex variables, Eglot
+
+This section provides a reference of the Eglot' user options.
+
+@vtable @code
+@item eglot-autoreconnect
+This option controls the ability to reconnect automatically to the
+language server when Eglot detects that the server process terminated
+unexpectedly.  The default value 3 means to attempt reconnection only
+if the previous successful connection lasted for more than that number
+of seconds; a different positive value changes the minimal length of
+the connection to trigger reconnection.  A value of @code{t} means
+always reconnect automatically, and @code{nil} means never reconnect.
+
+@item eglot-connect-timeout
+This specifies the number of seconds before connection attempt to a
+language server times out.  The value of @code{nil} means never time
+out.  The default is 30 seconds.
+
+@item eglot-sync-connect
+This setting is mainly important for connections which are slow to
+establish.  Whereas the variable @code{eglot-connect-timeout} controls
+how long to wait for, this variable controls whether to block Emacs's
+user interface while waiting.  The default value is 3; a positive
+value means block for that many seconds, then wait for the connection
+in the background.  The value of @code{t} means block during the whole
+waiting period.  The value of @code{nil} or zero means don't block at
+all during the waiting period.
+
+@item eglot-events-buffer-size
+This determines the size of the Eglot events buffer.  @xref{Eglot
+Commands, eglot-events-buffer}, for how to display that buffer.  If
+the value is changed, for it to take effect the connection should be
+restarted using @kbd{eglot-shutdown} followed by
+@kbd{eglot-reconnect}.
+@c FIXME: Shouldn't the defcustom do this by itself using the :set
+@c attribute?
+@xref{Troubleshooting Eglot}, for when this could be useful.
+
+@item eglot-autoshutdown
+If this is non-@code{nil}, Eglot shuts down a language server when the
+last buffer managed by it is killed.  @xref{Shutting Down LSP Servers}.
+The default is @code{nil}; if you want to shut down a server, use
+@kbd{M-x eglot-shutdown} (@pxref{Eglot Commands}).
+
+@item eglot-confirm-server-initiated-edits
+Various Eglot commands and code actions result in the language server
+sending editing commands to Emacs.  If this option's value is
+non-@code{nil} (the default), Eglot will ask for confirmation before
+performing edits initiated by the server or edits whose scope affects
+buffers other than the one where the user initiated the request.
+
+@item eglot-ignored-server-capabilities
+This variable's value is a list of language server capabilities that
+Eglot should not use.  The default is @code{nil}: Eglot uses all of
+the capabilities supported by each server.
+
+@item eglot-extend-to-xref
+If this is non-@code{nil}, and @kbd{M-.}
+(@code{xref-find-definitions}) lands you in a file outside of your
+project, such as a system-installed library or header file,
+transiently consider that file as managed by the same language server.
+That file is still outside your project (i.e. @code{project-find-file}
+won't find it), but Eglot and the server will consider it to be part
+of the workspace.  The default is @code{nil}.
+
+@item eglot-mode-map
+This variable is the keymap for binding Eglot-related command.  It is
+in effect only as long as the buffer is managed by Eglot.  By default,
+it is empty, with the single exception: @kbd{C-h .} is remapped to
+invoke @code{eldoc-doc-buffer}.  You can bind additional commands in
+this map.  For example:
+
+@lisp
+  (define-key eglot-mode-map (kbd "C-c r") 'eglot-rename)
+  (define-key eglot-mode-map (kbd "C-c o") 'eglot-code-action-organize-imports)
+  (define-key eglot-mode-map (kbd "C-c h") 'eldoc)
+  (define-key eglot-mode-map (kbd "<f6>") 'xref-find-definitions)
+@end lisp
+
+@end vtable
+
+Additional variables, which are relevant for customizing the server
+connections, are documented in @ref{Customizing Eglot}.
+
+@node Customizing Eglot
+@chapter Customizing Eglot
+@cindex customizing Eglot
+
+A large part of customizing Eglot to your needs and preferences should
+actually be done via options of the Emacs packages and features which
+Eglot supports and enhances (@pxref{Eglot Features}).  For example:
+
+@itemize @bullet
+@item
+To configure the face used for server-derived errors and warnings,
+customize the Flymake faces @code{flymake-error} and
+@code{flymake-error}.
+
+@item
+To configure the amount of space taken up by documentation in the
+echo area, customize the ElDoc variable
+@code{eldoc-echo-area-use-multiline-p}.
+
+@item
+To completely change how ElDoc displays the at-point documentation
+destination, customize the ElDoc variable
+@code{eldoc-display-functions}.
+@end itemize
+
+For this reason, this manual describes only how to customize the
+Eglot's own operation, which mainly has to do with the server
+connections and the server features to be used by Eglot.
+
+@c @table, not @vtable, because some of the variables are indexed
+@c elsewhere
+@table @code
+@item eglot-server-programs
+This variable determines which language server to start for each
+supported major mode, and how to invoke that server's program.
+@xref{Setting Up LSP Servers}, for the details.
+
+@vindex eglot-strict-mode
+@item eglot-strict-mode
+This is @code{nil} by default, meaning that Eglot is generally lenient
+about non-conforming servers.  If you need to debug a server, set this
+to @w{@code{(disallow-non-standard-keys enforce-required-keys)}}.
+
+@vindex eglot-server-initialized-hook
+@item eglot-server-initialized-hook
+A hook run after the server object is successfully initialized.
+
+@vindex eglot-connect-hook
+@item eglot-connect-hook
+A hook run after connection to the server is successfully
+established.  @xref{Starting Eglot}.
+
+@item eglot-managed-mode-hook
+A hook run after Eglot started or stopped managing a buffer.
+@xref{Eglot and Buffers}, for details of its usage.
+
+@vindex eglot-stay-out-of
+@item eglot-stay-out-of
+This variable's value lists Emacs features that Eglot shouldn't
+automatically try to manage on user's behalf.  It is useful, for
+example, when you need to use non-LSP Flymake or Company back-ends.
+To have Eglot stay away of some Emacs feature, add that feature's
+symbol or a regexp that will match a symbol's name to the list: for
+example, the symbol @code{xref} to leave Xref alone, or the string
+@samp{company} to stay away of your Company customizations.  Here's an
+example:
+
+@lisp
+(add-to-list 'eglot-stay-out-of 'flymake)
+@end lisp
+
+Note that you can still configure the excluded Emacs features manually
+to use Eglot in your @code{eglot-managed-mode-hook} or via some other
+mechanism.
+
+@vindex eglot-workspace-configuration
+@cindex server workspace configuration
+@item eglot-workspace-configuration
+This variable is meant to be set in the @file{.dir-locals.el} file, to
+provide per-project settings, as described below in more detail.
+@end table
+
+Some language servers need to know project-specific settings, which
+the LSP calls @dfn{workspace configuration}.  Eglot allows such fine
+tuning of per-project settings via the variable
+@code{eglot-workspace-configuration}.  Eglot sends the portion of the
+settings contained in this variable to each server for which such
+settings were defined in the variable.  These settings are
+communicated to the server initially (upon establishing the
+connection) or when the settings are changed, or in response to the
+configuration request from the server.
+
+In many cases, servers can be configured globally using a
+configuration file in the user's home directory or in the project
+directory, which the language server reads.  For example, the
+@command{pylsp} server for Python reads the file
+@file{~/.config/pycodestyle} and the @command{clangd} server reads the
+file @file{.clangd} anywhere in the current project's directory tree.
+If possible, we recommend to use these configuration files that are
+independent of Eglot and Emacs; they have the advantage that they will
+work with other LSP clients as well.
+
+If you do need to provide Emacs-specific configuration for a language
+server, we recommend to define the appropriate value in the
+@file{.dir-locals.el} file in the project's directory.  The value of
+this variable should be a property list of the following format:
+
+@lisp
+ (:@var{server} @var{plist}@dots{})
+@end lisp
+
+@noindent
+Here @code{:@var{server}} identifies a particular language server and
+@var{plist} is the corresponding keyword-value property list of one or
+more parameter settings for that server, serialized by Eglot as a JSON
+object.  @var{plist} may be arbitrarity complex, generally containing
+other keywork-value property sublists corresponding to JSON subobjects.
+The JSON values @code{true}, @code{false}, @code{null} and @code{@{@}}
+are represented by the Lisp values @code{t}, @code{:json-false},
+@code{nil}, and @code{eglot-@{@}}, respectively.
+
+@findex eglot-show-workspace-configuration
+When experimenting with workspace settings, you can use the command
+@kbd{M-x eglot-show-workspace-configuration} to inspect and debug the
+JSON value to be sent to the server.  This helper command works even
+before actually connecting to the server.
+
+Here's an example of defining the workspace-configuration settings for
+a project that uses two different language servers, one for Python,
+whose server is @command{pylsp}, the other one for Go, with
+@command{gopls} as its server (presumably, the project is written in a
+combination of these two languages):
+
+@lisp
+((python-mode
+  . ((eglot-workspace-configuration
+      . (:pylsp (:plugins (:jedi_completion (:include_params t
+                                             :fuzzy t)
+                           :pylint (:enabled :json-false)))))))
+ (go-mode
+  . ((eglot-workspace-configuration
+      . (:gopls (:usePlaceholders t))))))
+@end lisp
+
+@noindent
+This should go into the @file{.dir-locals.el} file in the project's
+root directory.  It sets up the value of
+@code{eglot-workspace-configuration} separately for each major mode.
+
+Alternatively, the same configuration could be defined as follows:
+
+@lisp
+((nil
+  . ((eglot-workspace-configuration
+      . (:pylsp (:plugins (:jedi_completion (:include_params t
+                                             :fuzzy t)
+                           :pylint (:enabled :json-false)))
+         :gopls (:usePlaceholders t))))))
+@end lisp
+
+This is an equivalent setup which sets the value for all the
+major-modes inside the project; Eglot will use for each server only
+the section of the parameters intended for that server.
+
+As yet another alternative, you can set the value of
+@code{eglot-workspace-configuration} programmatically, via the
+@code{dir-locals-set-class-variables} function, @pxref{Directory Local
+Variables,,, elisp, GNU Emacs Lisp Reference Manual}.
+
+Finally, if one needs to determine the workspace configuration based
+on some dynamic context, @code{eglot-workspace-configuration} can be
+set to a function.  The function is called with the
+@code{eglot-lsp-server} instance of the connected server (if any) and
+with @code{default-directory} set to the root of the project.  The
+function should return a value of the form described above.
+
+Some servers need special hand-holding to operate correctly.  If your
+server has some quirks or non-conformity, it's possible to extend
+Eglot via Elisp to adapt to it, by defining a suitable
+@code{eglot-initialization-options} method via @code{cl-defmethod}
+(@pxref{Generic Functions,,, elisp, GNU Emacs Lisp Reference Manual}).
+
+Here's an example:
+
+@lisp
+(add-to-list 'eglot-server-programs
+             '((c++ mode c-mode) . (eglot-cquery "cquery")))
+
+(defclass eglot-cquery (eglot-lsp-server) ()
+  :documentation "A custom class for cquery's C/C++ langserver.")
+
+(cl-defmethod eglot-initialization-options ((server eglot-cquery))
+  "Passes through required cquery initialization options"
+  (let* ((root (car (project-roots (eglot--project server))))
+         (cache (expand-file-name ".cquery_cached_index/" root)))
+    (list :cacheDirectory (file-name-as-directory cache)
+          :progressReportFrequencyMs -1)))
+@end lisp
+
+@noindent
+See the doc string of @code{eglot-initialization-options} for more
+details.
+@c FIXME: The doc string of eglot-initialization-options should be
+@c enhanced and extended.
+
+@node Troubleshooting Eglot
+@chapter Troubleshooting Eglot
+@cindex troubleshooting Eglot
+
+This section documents commands and variables that can be used to
+troubleshoot Eglot problems.  It also provides guidelines for
+reporting Eglot bugs in a way that facilitates their resolution.
+
+When you encounter problems with Eglot, try first using the commands
+@kbd{M-x eglot-events-server} and @kbd{M-x eglot-stderr-buffer}.  They
+pop up special buffers that can be used to inspect the communications
+between the Eglot and language server.  In many cases, this will
+indicate the problems or at least provide a hint.
+
+A common and easy-to-fix cause of performance problems is the length
+of these two buffers.  If Eglot is operating correctly but slowly,
+customize the variable @code{eglot-events-buffer-size} (@pxref{Eglot
+Variables}) to limit logging, and thus speed things up.
+
+If you need to report an Eglot bug, please keep in mind that, because
+there are so many variables involved, it is generally both very
+@emph{difficult} and @emph{absolutely essential} to reproduce bugs
+exactly as they happened to you, the user.  Therefore, every bug
+report should include:
+
+@enumerate
+@item
+The transcript of events obtained from the buffer popped up by
+@kbd{M-x eglot-events-buffer}.  If the transcript can be narrowed down
+to show the problematic exchange, so much the better.  This is
+invaluable for the investigation and reproduction of the problem.
+
+@item
+If Emacs signaled an error (an error message was seen or heard), make
+sure to repeat the process after toggling @code{debug-on-error} on
+(via @kbd{M-x toggle-debug-on-error}).  This normally produces a
+backtrace of the error that should also be attached to the bug report.
+
+@item
+An explanation how to obtain and install the language server you used.
+If possible, try to replicate the problem with the C/C@t{++} or Python
+servers, as these are very easy to install.
+
+@item
+A description of how to setup the @emph{minimal} project (one or two
+files and their contents) where the problem happens.
+
+@item
+A recipe to replicate the problem with @emph{a clean Emacs run}.  This
+means @kbd{emacs -Q} invocation or a very minimal (no more that 10
+lines) @file{.emacs} initialization file.  @code{eglot-ensure} and
+@code{use-package} calls are generally @emph{not} needed.
+
+@item
+Make sure to double check all the above elements and re-run the
+recipe to see that the problem is reproducible.
+@end enumerate
+
+Please keep in mind that some problems reported against Eglot may
+actually be bugs in the language server or the Emacs feature/package
+that used Eglot to communicate with the language server.
+
+@node GNU Free Documentation License
+@appendix GNU Free Documentation License
+@include doclicense.texi
+
+@node Index
+@unnumbered Index
+@printindex cp
+
+@bye
+        
diff --git a/lisp/info-look.el b/lisp/info-look.el
index ce0a08dcbe6..2eec6f49f5c 100644
--- a/lisp/info-look.el
+++ b/lisp/info-look.el
@@ -1051,6 +1051,7 @@ Return nil if there is nothing appropriate in the buffer near point."
    ("eieio" "Function Index")
    ("gnutls" "(emacs-gnutls)Variable Index" "(emacs-gnutls)Function Index")
    ("mm" "(emacs-mime)Index")
+   ("eglot" "Index")
    ("epa" "Variable Index" "Function Index")
    ("ert" "Index")
    ("eshell" "Function and Variable Index")
diff --git a/lisp/progmodes/eglot.el b/lisp/progmodes/eglot.el
new file mode 100644
index 00000000000..0a7cb2a9aac
--- /dev/null
+++ b/lisp/progmodes/eglot.el
@@ -0,0 +1,3457 @@
+;;; eglot.el --- The Emacs Client for LSP servers  -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2018-2022 Free Software Foundation, Inc.
+
+;; Version: 1.9
+;; Author: João Távora <joaotavora@gmail.com>
+;; Maintainer: João Távora <joaotavora@gmail.com>
+;; URL: https://github.com/joaotavora/eglot
+;; Keywords: convenience, languages
+;; Package-Requires: ((emacs "26.3") (jsonrpc "1.0.14") (flymake "1.2.1") (project "0.3.0") (xref "1.0.1") (eldoc "1.11.0") (seq "2.23"))
+
+;; This is is a GNU ELPA :core package.  Avoid adding functionality
+;; that is not available in the version of Emacs recorded above or any
+;; of the package dependencies.
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs is free software: you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; Eglot ("Emacs Polyglot") is an Emacs LSP client that stays out of
+;; your way.
+;;
+;; Typing M-x eglot in some source file is often enough to get you
+;; started, if the language server you're looking to use is installed
+;; in your system.  Please refer to the manual, available from
+;; https://joaotavora.github.io/eglot/ or from M-x info for more usage
+;; instructions.
+;;
+;; If you wish to contribute changes to Eglot, please do read the user
+;; manual first.  Additionally, take the following in consideration:
+
+;; * Eglot's main job is to hook up the information that language
+;;   servers offer via LSP to Emacs's UI facilities: Xref for
+;;   definition-chasing, Flymake for diagnostics, Eldoc for at-point
+;;   documentation, etc.  Eglot's job is generally *not* to provide
+;;   such a UI itself, though a small number of simple
+;;   counter-examples do exist, for example in the `eglot-rename'
+;;   command.  When a new UI is evidently needed, consider adding a
+;;   new package to Emacs, or extending an existing one.
+;;
+;; * Eglot was designed to function with just the UI facilities found
+;;   in the latest Emacs core, as long as those facilities are also
+;;   available as GNU ELPA :core packages.  Historically, a number of
+;;   :core packages were added or reworked in Emacs to make this
+;;   possible.  This principle should be upheld when adding new LSP
+;;   features or tweaking exising ones.  Design any new facilities in
+;;   a way that they could work in the absence of LSP or using some
+;;   different protocol, then make sure Eglot can link up LSP
+;;   information to it.
+
+;; * There are few Eglot configuration variables.  This principle
+;;   should also be upheld.  If Eglot had these variables, it could be
+;;   duplicating configuration found elsewhere, bloating itself up,
+;;   and making it generally hard to integrate with the ever growing
+;;   set of LSP features and Emacs packages.  For instance, this is
+;;   why one finds a single variable
+;;   `eglot-ignored-server-capabilities' instead of a number of
+;;   capability-specific flags, or why customizing the display of
+;;   LSP-provided documentation is done via ElDoc's variables, not
+;;   Eglot's.
+;;
+;; * Linking up LSP information to other libraries is generally done
+;;   in the `eglot--managed-mode' minor mode function, by
+;;   buffer-locally setting the other library's variables to
+;;   Eglot-specific versions.  When deciding what to set the variable
+;;   to, the general idea is to choose a good default for beginners
+;;   that doesn't clash with Emacs's defaults.  The settings are only
+;;   in place during Eglot's LSP-enriched tenure over a project.  Even
+;;   so, some of those decisions will invariably aggravate a minority
+;;   of Emacs power users, but these users can use `eglot-stay-out-of'
+;;   and `eglot-managed-mode-hook' to quench their OCD.
+;;
+;; * On occasion, to enable new features, Eglot can have soft
+;;   dependencies on popular libraries that are not in Emacs core.
+;;   "Soft" means that the dependency doesn't impair any other use of
+;;   Eglot beyond that feature.  Such is the case of the snippet
+;;   functionality, via the Yasnippet package, Markdown formatting of
+;;   at-point documentation via the markdown-mode package, and nicer
+;;   looking completions when the Company package is used.
+
+;;; Code:
+
+(require 'imenu)
+(require 'cl-lib)
+(require 'project)
+(require 'url-parse)
+(require 'url-util)
+(require 'pcase)
+(require 'compile) ; for some faces
+(require 'warnings)
+(require 'flymake)
+(require 'xref)
+(eval-when-compile
+  (require 'subr-x))
+(require 'jsonrpc)
+(require 'filenotify)
+(require 'ert)
+(require 'array)
+
+;; ElDoc is preloaded in Emacs, so `require'-ing won't guarantee we are
+;; using the latest version from GNU Elpa when we load eglot.el.  Use an
+;; heuristic to see if we need to `load' it in Emacs < 28.
+(if (and (< emacs-major-version 28)
+         (not (boundp 'eldoc-documentation-strategy)))
+    (load "eldoc")
+  (require 'eldoc))
+
+;; Similar issue as above for Emacs 26.3 and seq.el.
+(if (< emacs-major-version 27)
+    (load "seq")
+  (require 'seq))
+
+;; forward-declare, but don't require (Emacs 28 doesn't seem to care)
+(defvar markdown-fontify-code-blocks-natively)
+(defvar company-backends)
+(defvar company-tooltip-align-annotations)
+
+
+
+;;; User tweakable stuff
+(defgroup eglot nil
+  "Interaction with Language Server Protocol servers."
+  :prefix "eglot-"
+  :group 'applications)
+
+(defun eglot-alternatives (alternatives)
+  "Compute server-choosing function for `eglot-server-programs'.
+Each element of ALTERNATIVES is a string PROGRAM or a list of
+strings (PROGRAM ARGS...) where program names an LSP server
+program to start with ARGS.  Returns a function of one argument.
+When invoked, that function will return a list (ABSPATH ARGS),
+where ABSPATH is the absolute path of the PROGRAM that was
+chosen (interactively or automatically)."
+  (lambda (&optional interactive)
+    ;; JT@2021-06-13: This function is way more complicated than it
+    ;; could be because it accounts for the fact that
+    ;; `eglot--executable-find' may take much longer to execute on
+    ;; remote files.
+    (let* ((listified (cl-loop for a in alternatives
+                               collect (if (listp a) a (list a))))
+           (err (lambda ()
+                  (error "None of '%s' are valid executables"
+                         (mapconcat #'car listified ", ")))))
+      (cond (interactive
+             (let* ((augmented (mapcar (lambda (a)
+                                         (let ((found (eglot--executable-find
+                                                       (car a) t)))
+                                           (and found
+                                                (cons (car a) (cons found (cdr a))))))
+                                       listified))
+                    (available (remove nil augmented)))
+               (cond ((cdr available)
+                      (cdr (assoc
+                            (completing-read
+                             "[eglot] More than one server executable available:"
+                             (mapcar #'car available)
+                             nil t nil nil (car (car available)))
+                            available #'equal)))
+                     ((cdr (car available)))
+                     (t
+                      ;; Don't error when used interactively, let the
+                      ;; Eglot prompt the user for alternative (github#719)
+                      nil))))
+            (t
+             (cl-loop for (p . args) in listified
+                      for probe = (eglot--executable-find p t)
+                      when probe return (cons probe args)
+                      finally (funcall err)))))))
+
+(defvar eglot-server-programs `((rust-mode . ,(eglot-alternatives '("rust-analyzer" "rls")))
+                                (cmake-mode . ("cmake-language-server"))
+                                (vimrc-mode . ("vim-language-server" "--stdio"))
+                                (python-mode
+                                 . ,(eglot-alternatives
+                                     '("pylsp" "pyls" ("pyright-langserver" "--stdio") "jedi-language-server")))
+                                ((js-mode typescript-mode)
+                                 . ("typescript-language-server" "--stdio"))
+                                (sh-mode . ("bash-language-server" "start"))
+                                ((php-mode phps-mode)
+                                 . ("php" "vendor/felixfbecker/\
+language-server/bin/php-language-server.php"))
+                                ((c++-mode c-mode) . ,(eglot-alternatives
+                                                       '("clangd" "ccls")))
+                                (((caml-mode :language-id "ocaml")
+                                  (tuareg-mode :language-id "ocaml") reason-mode)
+                                 . ("ocamllsp"))
+                                (ruby-mode
+                                 . ("solargraph" "socket" "--port" :autoport))
+                                (haskell-mode
+                                 . ("haskell-language-server-wrapper" "--lsp"))
+                                (elm-mode . ("elm-language-server"))
+                                (mint-mode . ("mint" "ls"))
+                                (kotlin-mode . ("kotlin-language-server"))
+                                (go-mode . ("gopls"))
+                                ((R-mode ess-r-mode) . ("R" "--slave" "-e"
+                                                        "languageserver::run()"))
+                                (java-mode . ("jdtls"))
+                                (dart-mode . ("dart" "language-server"
+                                              "--client-id" "emacs.eglot-dart"))
+                                (elixir-mode . ("language_server.sh"))
+                                (ada-mode . ("ada_language_server"))
+                                (scala-mode . ("metals-emacs"))
+                                (racket-mode . ("racket" "-l" "racket-langserver"))
+                                ((tex-mode context-mode texinfo-mode bibtex-mode)
+                                 . ("digestif"))
+                                (erlang-mode . ("erlang_ls" "--transport" "stdio"))
+                                (yaml-mode . ("yaml-language-server" "--stdio"))
+                                (nix-mode . ("rnix-lsp"))
+                                (gdscript-mode . ("localhost" 6008))
+                                ((fortran-mode f90-mode) . ("fortls"))
+                                (futhark-mode . ("futhark" "lsp"))
+                                (lua-mode . ("lua-lsp"))
+                                (zig-mode . ("zls"))
+                                (css-mode . ,(eglot-alternatives '(("vscode-css-language-server" "--stdio") ("css-languageserver" "--stdio"))))
+                                (html-mode . ,(eglot-alternatives '(("vscode-html-language-server" "--stdio") ("html-languageserver" "--stdio"))))
+                                (json-mode . ,(eglot-alternatives '(("vscode-json-language-server" "--stdio") ("json-languageserver" "--stdio"))))
+                                (dockerfile-mode . ("docker-langserver" "--stdio"))
+                                ((clojure-mode clojurescript-mode clojurec-mode) 
+                                 . ("clojure-lsp"))
+                                (csharp-mode . ("omnisharp" "-lsp"))
+                                (purescript-mode . ("purescript-language-server" "--stdio"))
+                                (perl-mode . ("perl" "-MPerl::LanguageServer" "-e" "Perl::LanguageServer::run"))
+                                (markdown-mode . ("marksman" "server")))
+  "How the command `eglot' guesses the server to start.
+An association list of (MAJOR-MODE . CONTACT) pairs.  MAJOR-MODE
+identifies the buffers that are to be managed by a specific
+language server.  The associated CONTACT specifies how to connect
+to a server for those buffers.
+
+MAJOR-MODE can be:
+
+* In the most common case, a symbol such as `c-mode';
+
+* A list (MAJOR-MODE-SYMBOL :LANGUAGE-ID ID) where
+  MAJOR-MODE-SYMBOL is the aforementioned symbol and ID is a
+  string identifying the language to the server;
+
+* A list combining the previous two alternatives, meaning
+  multiple major modes will be associated with a single server
+  program.  This association is such that the same resulting
+  server process will manage buffers of different major modes.
+
+CONTACT can be:
+
+* In the most common case, a list of strings (PROGRAM [ARGS...]).
+  PROGRAM is called with ARGS and is expected to serve LSP requests
+  over the standard input/output channels.
+
+* A list (PROGRAM [ARGS...] :initializationOptions OPTIONS),
+  whereupon PROGRAM is called with ARGS as in the first option,
+  and the LSP \"initializationOptions\" JSON object is
+  constructed from OPTIONS.  If OPTIONS is a unary function, it
+  is called with the server instance and should return a JSON
+  object.
+
+* A list (HOST PORT [TCP-ARGS...]) where HOST is a string and
+  PORT is a positive integer for connecting to a server via TCP.
+  Remaining ARGS are passed to `open-network-stream' for
+  upgrading the connection with encryption or other capabilities.
+
+* A list (PROGRAM [ARGS...] :autoport [MOREARGS...]), whereupon a
+  combination of previous options is used.  First, an attempt is
+  made to find an available server port, then PROGRAM is launched
+  with ARGS; the `:autoport' keyword substituted for that number;
+  and MOREARGS.  Eglot then attempts to establish a TCP
+  connection to that port number on the localhost.
+
+* A cons (CLASS-NAME . INITARGS) where CLASS-NAME is a symbol
+  designating a subclass of `eglot-lsp-server', for representing
+  experimental LSP servers.  INITARGS is a keyword-value plist
+  used to initialize the object of CLASS-NAME, or a plain list
+  interpreted as the previous descriptions of CONTACT.  In the
+  latter case that plain list is used to produce a plist with a
+  suitable :PROCESS initarg to CLASS-NAME.  The class
+  `eglot-lsp-server' descends from `jsonrpc-process-connection',
+  which you should see for the semantics of the mandatory
+  :PROCESS argument.
+
+* A function of a single argument producing any of the above
+  values for CONTACT.  The argument's value is non-nil if the
+  connection was requested interactively (e.g. from the `eglot'
+  command), and nil if it wasn't (e.g. from `eglot-ensure').  If
+  the call is interactive, the function can ask the user for
+  hints on finding the required programs, etc.  Otherwise, it
+  should not ask the user for any input, and return nil or signal
+  an error if it can't produce a valid CONTACT.")
+
+(defface eglot-highlight-symbol-face
+  '((t (:inherit bold)))
+  "Face used to highlight the symbol at point.")
+
+(defface eglot-mode-line
+  '((t (:inherit font-lock-constant-face :weight bold)))
+  "Face for package-name in Eglot's mode line.")
+
+(defface eglot-diagnostic-tag-unnecessary-face
+  '((t (:inherit shadow)))
+  "Face used to render unused or unnecessary code.")
+
+(defface eglot-diagnostic-tag-deprecated-face
+  '((t . (:inherit shadow :strike-through t)))
+  "Face used to render deprecated or obsolete code.")
+
+(defcustom eglot-autoreconnect 3
+  "Control ability to reconnect automatically to the LSP server.
+If t, always reconnect automatically (not recommended).  If nil,
+never reconnect automatically after unexpected server shutdowns,
+crashes or network failures.  A positive integer number says to
+only autoreconnect if the previous successful connection attempt
+lasted more than that many seconds."
+  :type '(choice (boolean :tag "Whether to inhibit autoreconnection")
+                 (integer :tag "Number of seconds")))
+
+(defcustom eglot-connect-timeout 30
+  "Number of seconds before timing out LSP connection attempts.
+If nil, never time out."
+  :type 'number)
+
+(defcustom eglot-sync-connect 3
+  "Control blocking of LSP connection attempts.
+If t, block for `eglot-connect-timeout' seconds.  A positive
+integer number means block for that many seconds, and then wait
+for the connection in the background.  nil has the same meaning
+as 0, i.e. don't block at all."
+  :type '(choice (boolean :tag "Whether to inhibit autoreconnection")
+                 (integer :tag "Number of seconds")))
+
+(defcustom eglot-autoshutdown nil
+  "If non-nil, shut down server after killing last managed buffer."
+  :type 'boolean)
+
+(defcustom eglot-send-changes-idle-time 0.5
+  "Don't tell server of changes before Emacs's been idle for this many seconds."
+  :type 'number)
+
+(defcustom eglot-events-buffer-size 2000000
+  "Control the size of the Eglot events buffer.
+If a number, don't let the buffer grow larger than that many
+characters.  If 0, don't use an event's buffer at all.  If nil,
+let the buffer grow forever.
+
+For changes on this variable to take effect on a connection
+already started, you need to restart the connection.  That can be
+done by `eglot-reconnect'."
+  :type '(choice (const :tag "No limit" nil)
+                 (integer :tag "Number of characters")))
+
+(defcustom eglot-confirm-server-initiated-edits 'confirm
+  "Non-nil if server-initiated edits should be confirmed with user."
+  :type '(choice (const :tag "Don't show confirmation prompt" nil)
+                 (symbol :tag "Show confirmation prompt" 'confirm)))
+
+(defcustom eglot-extend-to-xref nil
+  "If non-nil, activate Eglot in cross-referenced non-project files."
+  :type 'boolean)
+
+(defcustom eglot-menu-string "eglot"
+  "String displayed in mode line when Eglot is active."
+  :type 'string)
+
+(defvar eglot-withhold-process-id nil
+  "If non-nil, Eglot will not send the Emacs process id to the language server.
+This can be useful when using docker to run a language server.")
+
+;; Customizable via `completion-category-overrides'.
+(when (assoc 'flex completion-styles-alist)
+  (add-to-list 'completion-category-defaults '(eglot (styles flex basic))))
+
+
+;;; Constants
+;;;
+(defconst eglot--symbol-kind-names
+  `((1 . "File") (2 . "Module")
+    (3 . "Namespace") (4 . "Package") (5 . "Class")
+    (6 . "Method") (7 . "Property") (8 . "Field")
+    (9 . "Constructor") (10 . "Enum") (11 . "Interface")
+    (12 . "Function") (13 . "Variable") (14 . "Constant")
+    (15 . "String") (16 . "Number") (17 . "Boolean")
+    (18 . "Array") (19 . "Object") (20 . "Key")
+    (21 . "Null") (22 . "EnumMember") (23 . "Struct")
+    (24 . "Event") (25 . "Operator") (26 . "TypeParameter")))
+
+(defconst eglot--kind-names
+  `((1 . "Text") (2 . "Method") (3 . "Function") (4 . "Constructor")
+    (5 . "Field") (6 . "Variable") (7 . "Class") (8 . "Interface")
+    (9 . "Module") (10 . "Property") (11 . "Unit") (12 . "Value")
+    (13 . "Enum") (14 . "Keyword") (15 . "Snippet") (16 . "Color")
+    (17 . "File") (18 . "Reference") (19 . "Folder") (20 . "EnumMember")
+    (21 . "Constant") (22 . "Struct") (23 . "Event") (24 . "Operator")
+    (25 . "TypeParameter")))
+
+(defconst eglot--tag-faces
+  `((1 . eglot-diagnostic-tag-unnecessary-face)
+    (2 . eglot-diagnostic-tag-deprecated-face)))
+
+(defvaralias 'eglot-{} 'eglot--{})
+(defconst eglot--{} (make-hash-table :size 1) "The empty JSON object.")
+
+(defun eglot--executable-find (command &optional remote)
+  "Like Emacs 27's `executable-find', ignore REMOTE on Emacs 26."
+  (if (>= emacs-major-version 27) (executable-find command remote)
+    (executable-find command)))
+
+
+;;; Message verification helpers
+;;;
+(eval-and-compile
+  (defvar eglot--lsp-interface-alist
+    `(
+      (CodeAction (:title) (:kind :diagnostics :edit :command :isPreferred))
+      (ConfigurationItem () (:scopeUri :section))
+      (Command ((:title . string) (:command . string)) (:arguments))
+      (CompletionItem (:label)
+                      (:kind :detail :documentation :deprecated :preselect
+                             :sortText :filterText :insertText :insertTextFormat
+                             :textEdit :additionalTextEdits :commitCharacters
+                             :command :data :tags))
+      (Diagnostic (:range :message) (:severity :code :source :relatedInformation :codeDescription :tags))
+      (DocumentHighlight (:range) (:kind))
+      (FileSystemWatcher (:globPattern) (:kind))
+      (Hover (:contents) (:range))
+      (InitializeResult (:capabilities) (:serverInfo))
+      (Location (:uri :range))
+      (LocationLink (:targetUri :targetRange :targetSelectionRange) (:originSelectionRange))
+      (LogMessageParams (:type :message))
+      (MarkupContent (:kind :value))
+      (ParameterInformation (:label) (:documentation))
+      (Position (:line :character))
+      (Range (:start :end))
+      (Registration (:id :method) (:registerOptions))
+      (ResponseError (:code :message) (:data))
+      (ShowMessageParams (:type :message))
+      (ShowMessageRequestParams (:type :message) (:actions))
+      (SignatureHelp (:signatures) (:activeSignature :activeParameter))
+      (SignatureInformation (:label) (:documentation :parameters :activeParameter))
+      (SymbolInformation (:name :kind :location)
+                         (:deprecated :containerName))
+      (DocumentSymbol (:name :range :selectionRange :kind)
+                      ;; `:containerName' isn't really allowed , but
+                      ;; it simplifies the impl of `eglot-imenu'.
+                      (:detail :deprecated :children :containerName))
+      (TextDocumentEdit (:textDocument :edits) ())
+      (TextEdit (:range :newText))
+      (VersionedTextDocumentIdentifier (:uri :version) ())
+      (WorkspaceEdit () (:changes :documentChanges))
+      (WorkspaceSymbol (:name :kind) (:containerName :location :data)))
+    "Alist (INTERFACE-NAME . INTERFACE) of known external LSP interfaces.
+
+INTERFACE-NAME is a symbol designated by the spec as
+\"interface\".  INTERFACE is a list (REQUIRED OPTIONAL) where
+REQUIRED and OPTIONAL are lists of KEYWORD designating field
+names that must be, or may be, respectively, present in a message
+adhering to that interface.  KEY can be a keyword or a cons (SYM
+TYPE), where type is used by `cl-typep' to check types at
+runtime.
+
+Here's what an element of this alist might look like:
+
+    (Command ((:title . string) (:command . string)) (:arguments))"))
+
+(eval-and-compile
+  (defvar eglot-strict-mode
+    '(;; Uncomment next lines for fun and debugging
+      ;; disallow-non-standard-keys
+      ;; enforce-required-keys
+      ;; enforce-optional-keys
+      )
+    "How strictly to check LSP interfaces at compile- and run-time.
+
+Value is a list of symbols (if the list is empty, no checks are
+performed).
+
+If the symbol `disallow-non-standard-keys' is present, an error
+is raised if any extraneous fields are sent by the server.  At
+compile-time, a warning is raised if a destructuring spec
+includes such a field.
+
+If the symbol `enforce-required-keys' is present, an error is
+raised if any required fields are missing from the message sent
+from the server.  At compile-time, a warning is raised if a
+destructuring spec doesn't use such a field.
+
+If the symbol `enforce-optional-keys' is present, nothing special
+happens at run-time.  At compile-time, a warning is raised if a
+destructuring spec doesn't use all optional fields.
+
+If the symbol `disallow-unknown-methods' is present, Eglot warns
+on unknown notifications and errors on unknown requests."))
+
+(cl-defun eglot--check-object (interface-name
+                               object
+                               &optional
+                               (enforce-required t)
+                               (disallow-non-standard t)
+                               (check-types t))
+  "Check that OBJECT conforms to INTERFACE.  Error otherwise."
+  (cl-destructuring-bind
+      (&key types required-keys optional-keys &allow-other-keys)
+      (eglot--interface interface-name)
+    (when-let ((missing (and enforce-required
+                             (cl-set-difference required-keys
+                                                (eglot--plist-keys object)))))
+      (eglot--error "A `%s' must have %s" interface-name missing))
+    (when-let ((excess (and disallow-non-standard
+                            (cl-set-difference
+                             (eglot--plist-keys object)
+                             (append required-keys optional-keys)))))
+      (eglot--error "A `%s' mustn't have %s" interface-name excess))
+    (when check-types
+      (cl-loop
+       for (k v) on object by #'cddr
+       for type = (or (cdr (assoc k types)) t) ;; FIXME: enforce nil type?
+       unless (cl-typep v type)
+       do (eglot--error "A `%s' must have a %s as %s, but has %s"
+                        interface-name )))
+    t))
+
+(eval-and-compile
+  (defun eglot--keywordize-vars (vars)
+    (mapcar (lambda (var) (intern (format ":%s" var))) vars))
+
+  (defun eglot--ensure-type (k) (if (consp k) k (cons k t)))
+
+  (defun eglot--interface (interface-name)
+    (let* ((interface (assoc interface-name eglot--lsp-interface-alist))
+           (required (mapcar #'eglot--ensure-type (car (cdr interface))))
+           (optional (mapcar #'eglot--ensure-type (cadr (cdr interface)))))
+      (list :types (append required optional)
+            :required-keys (mapcar #'car required)
+            :optional-keys (mapcar #'car optional))))
+
+  (defun eglot--check-dspec (interface-name dspec)
+    "Check destructuring spec DSPEC against INTERFACE-NAME."
+    (cl-destructuring-bind (&key required-keys optional-keys &allow-other-keys)
+        (eglot--interface interface-name)
+      (cond ((or required-keys optional-keys)
+             (let ((too-many
+                    (and
+                     (memq 'disallow-non-standard-keys eglot-strict-mode)
+                     (cl-set-difference
+                      (eglot--keywordize-vars dspec)
+                      (append required-keys optional-keys))))
+                   (ignored-required
+                    (and
+                     (memq 'enforce-required-keys eglot-strict-mode)
+                     (cl-set-difference
+                      required-keys (eglot--keywordize-vars dspec))))
+                   (missing-out
+                    (and
+                     (memq 'enforce-optional-keys eglot-strict-mode)
+                     (cl-set-difference
+                      optional-keys (eglot--keywordize-vars dspec)))))
+               (when too-many (byte-compile-warn
+                               "Destructuring for %s has extraneous %s"
+                               interface-name too-many))
+               (when ignored-required (byte-compile-warn
+                                       "Destructuring for %s ignores required %s"
+                                       interface-name ignored-required))
+               (when missing-out (byte-compile-warn
+                                  "Destructuring for %s is missing out on %s"
+                                  interface-name missing-out))))
+            (t
+             (byte-compile-warn "Unknown LSP interface %s" interface-name))))))
+
+(cl-defmacro eglot--dbind (vars object &body body)
+  "Destructure OBJECT, binding VARS in BODY.
+VARS is ([(INTERFACE)] SYMS...)
+Honour `eglot-strict-mode'."
+  (declare (indent 2) (debug (sexp sexp &rest form)))
+  (let ((interface-name (if (consp (car vars))
+                            (car (pop vars))))
+        (object-once (make-symbol "object-once"))
+        (fn-once (make-symbol "fn-once")))
+    (cond (interface-name
+           (eglot--check-dspec interface-name vars)
+           `(let ((,object-once ,object))
+              (cl-destructuring-bind (&key ,@vars &allow-other-keys) ,object-once
+                (eglot--check-object ',interface-name ,object-once
+                                     (memq 'enforce-required-keys eglot-strict-mode)
+                                     (memq 'disallow-non-standard-keys eglot-strict-mode)
+                                     (memq 'check-types eglot-strict-mode))
+                ,@body)))
+          (t
+           `(let ((,object-once ,object)
+                  (,fn-once (lambda (,@vars) ,@body)))
+              (if (memq 'disallow-non-standard-keys eglot-strict-mode)
+                  (cl-destructuring-bind (&key ,@vars) ,object-once
+                    (funcall ,fn-once ,@vars))
+                (cl-destructuring-bind (&key ,@vars &allow-other-keys) ,object-once
+                  (funcall ,fn-once ,@vars))))))))
+
+
+(cl-defmacro eglot--lambda (cl-lambda-list &body body)
+  "Function of args CL-LAMBDA-LIST for processing INTERFACE objects.
+Honour `eglot-strict-mode'."
+  (declare (indent 1) (debug (sexp &rest form)))
+  (let ((e (cl-gensym "jsonrpc-lambda-elem")))
+    `(lambda (,e) (eglot--dbind ,cl-lambda-list ,e ,@body))))
+
+(cl-defmacro eglot--dcase (obj &rest clauses)
+  "Like `pcase', but for the LSP object OBJ.
+CLAUSES is a list (DESTRUCTURE FORMS...) where DESTRUCTURE is
+treated as in `eglot-dbind'."
+  (declare (indent 1) (debug (sexp &rest (sexp &rest form))))
+  (let ((obj-once (make-symbol "obj-once")))
+    `(let ((,obj-once ,obj))
+       (cond
+        ,@(cl-loop
+           for (vars . body) in clauses
+           for vars-as-keywords = (eglot--keywordize-vars vars)
+           for interface-name = (if (consp (car vars))
+                                    (car (pop vars)))
+           for condition =
+           (cond (interface-name
+                  (eglot--check-dspec interface-name vars)
+                  ;; In this mode, in runtime, we assume
+                  ;; `eglot-strict-mode' is partially on, otherwise we
+                  ;; can't disambiguate between certain types.
+                  `(ignore-errors
+                     (eglot--check-object
+                      ',interface-name ,obj-once
+                      t
+                      (memq 'disallow-non-standard-keys eglot-strict-mode)
+                      t)))
+                 (t
+                  ;; In this interface-less mode we don't check
+                  ;; `eglot-strict-mode' at all: just check that the object
+                  ;; has all the keys the user wants to destructure.
+                  `(null (cl-set-difference
+                          ',vars-as-keywords
+                          (eglot--plist-keys ,obj-once)))))
+           collect `(,condition
+                     (cl-destructuring-bind (&key ,@vars &allow-other-keys)
+                         ,obj-once
+                       ,@body)))
+        (t
+         (eglot--error "%S didn't match any of %S"
+                       ,obj-once
+                       ',(mapcar #'car clauses)))))))
+
+
+;;; API (WORK-IN-PROGRESS!)
+;;;
+(cl-defmacro eglot--when-live-buffer (buf &rest body)
+  "Check BUF live, then do BODY in it." (declare (indent 1) (debug t))
+  (let ((b (cl-gensym)))
+    `(let ((,b ,buf)) (if (buffer-live-p ,b) (with-current-buffer ,b ,@body)))))
+
+(cl-defmacro eglot--when-buffer-window (buf &body body)
+  "Check BUF showing somewhere, then do BODY in it." (declare (indent 1) (debug t))
+  (let ((b (cl-gensym)))
+    `(let ((,b ,buf))
+       ;;notice the exception when testing with `ert'
+       (when (or (get-buffer-window ,b) (ert-running-test))
+         (with-current-buffer ,b ,@body)))))
+
+(cl-defmacro eglot--widening (&rest body)
+  "Save excursion and restriction.  Widen.  Then run BODY." (declare (debug t))
+  `(save-excursion (save-restriction (widen) ,@body)))
+
+(cl-defgeneric eglot-handle-request (server method &rest params)
+  "Handle SERVER's METHOD request with PARAMS.")
+
+(cl-defgeneric eglot-handle-notification (server method &rest params)
+  "Handle SERVER's METHOD notification with PARAMS.")
+
+(cl-defgeneric eglot-execute-command (server command arguments)
+  "Ask SERVER to execute COMMAND with ARGUMENTS.")
+
+(cl-defgeneric eglot-initialization-options (server)
+  "JSON object to send under `initializationOptions'."
+  (:method (s)
+   (let ((probe (plist-get (eglot--saved-initargs s) :initializationOptions)))
+     (cond ((functionp probe) (funcall probe s))
+           (probe)
+           (t eglot--{})))))
+
+(cl-defgeneric eglot-register-capability (server method id &rest params)
+  "Ask SERVER to register capability METHOD marked with ID."
+  (:method
+   (_s method _id &rest _params)
+   (eglot--warn "Server tried to register unsupported capability `%s'"
+                method)))
+
+(cl-defgeneric eglot-unregister-capability (server method id &rest params)
+  "Ask SERVER to register capability METHOD marked with ID."
+  (:method
+   (_s method _id &rest _params)
+   (eglot--warn "Server tried to unregister unsupported capability `%s'"
+                method)))
+
+(cl-defgeneric eglot-client-capabilities (server)
+  "What the Eglot LSP client supports for SERVER."
+  (:method (s)
+           (list
+            :workspace (list
+                        :applyEdit t
+                        :executeCommand `(:dynamicRegistration :json-false)
+                        :workspaceEdit `(:documentChanges t)
+                        :didChangeWatchedFiles
+                        `(:dynamicRegistration
+                          ,(if (eglot--trampish-p s) :json-false t))
+                        :symbol `(:dynamicRegistration :json-false)
+                        :configuration t
+                        :workspaceFolders t)
+            :textDocument
+            (list
+             :synchronization (list
+                               :dynamicRegistration :json-false
+                               :willSave t :willSaveWaitUntil t :didSave t)
+             :completion      (list :dynamicRegistration :json-false
+                                    :completionItem
+                                    `(:snippetSupport
+                                      ,(if (eglot--snippet-expansion-fn)
+                                           t
+                                         :json-false)
+                                      :deprecatedSupport t
+                                      :tagSupport (:valueSet [1]))
+                                    :contextSupport t)
+             :hover              (list :dynamicRegistration :json-false
+                                       :contentFormat
+                                       (if (fboundp 'gfm-view-mode)
+                                           ["markdown" "plaintext"]
+                                         ["plaintext"]))
+             :signatureHelp      (list :dynamicRegistration :json-false
+                                       :signatureInformation
+                                       `(:parameterInformation
+                                         (:labelOffsetSupport t)
+                                         :activeParameterSupport t))
+             :references         `(:dynamicRegistration :json-false)
+             :definition         (list :dynamicRegistration :json-false
+                                       :linkSupport t)
+             :declaration        (list :dynamicRegistration :json-false
+                                       :linkSupport t)
+             :implementation     (list :dynamicRegistration :json-false
+                                       :linkSupport t)
+             :typeDefinition     (list :dynamicRegistration :json-false
+                                       :linkSupport t)
+             :documentSymbol     (list
+                                  :dynamicRegistration :json-false
+                                  :hierarchicalDocumentSymbolSupport t
+                                  :symbolKind `(:valueSet
+                                                [,@(mapcar
+                                                    #'car eglot--symbol-kind-names)]))
+             :documentHighlight  `(:dynamicRegistration :json-false)
+             :codeAction         (list
+                                  :dynamicRegistration :json-false
+                                  :codeActionLiteralSupport
+                                  '(:codeActionKind
+                                    (:valueSet
+                                     ["quickfix"
+                                      "refactor" "refactor.extract"
+                                      "refactor.inline" "refactor.rewrite"
+                                      "source" "source.organizeImports"]))
+                                  :isPreferredSupport t)
+             :formatting         `(:dynamicRegistration :json-false)
+             :rangeFormatting    `(:dynamicRegistration :json-false)
+             :rename             `(:dynamicRegistration :json-false)
+             :publishDiagnostics (list :relatedInformation :json-false
+                                       ;; TODO: We can support :codeDescription after
+                                       ;; adding an appropriate UI to
+                                       ;; Flymake.
+                                       :codeDescriptionSupport :json-false
+                                       :tagSupport
+                                       `(:valueSet
+                                         [,@(mapcar
+                                             #'car eglot--tag-faces)])))
+            :experimental eglot--{})))
+
+(cl-defgeneric eglot-workspace-folders (server)
+  "Return workspaceFolders for SERVER."
+  (let ((project (eglot--project server)))
+    (vconcat
+     (mapcar (lambda (dir)
+               (list :uri (eglot--path-to-uri dir)
+                     :name (abbreviate-file-name dir)))
+             `(,(project-root project) ,@(project-external-roots project))))))
+
+(defclass eglot-lsp-server (jsonrpc-process-connection)
+  ((project-nickname
+    :documentation "Short nickname for the associated project."
+    :accessor eglot--project-nickname
+    :reader eglot-project-nickname)
+   (major-modes
+    :documentation "Major modes server is responsible for in a given project."
+    :accessor eglot--major-modes)
+   (language-id
+    :documentation "Language ID string for the mode."
+    :accessor eglot--language-id)
+   (capabilities
+    :documentation "JSON object containing server capabilities."
+    :accessor eglot--capabilities)
+   (server-info
+    :documentation "JSON object containing server info."
+    :accessor eglot--server-info)
+   (shutdown-requested
+    :documentation "Flag set when server is shutting down."
+    :accessor eglot--shutdown-requested)
+   (project
+    :documentation "Project associated with server."
+    :accessor eglot--project)
+   (spinner
+    :documentation "List (ID DOING-WHAT DONE-P) representing server progress."
+    :initform `(nil nil t) :accessor eglot--spinner)
+   (inhibit-autoreconnect
+    :initform t
+    :documentation "Generalized boolean inhibiting auto-reconnection if true."
+    :accessor eglot--inhibit-autoreconnect)
+   (file-watches
+    :documentation "Map ID to list of WATCHES for `didChangeWatchedFiles'."
+    :initform (make-hash-table :test #'equal) :accessor eglot--file-watches)
+   (managed-buffers
+    :documentation "List of buffers managed by server."
+    :accessor eglot--managed-buffers)
+   (saved-initargs
+    :documentation "Saved initargs for reconnection purposes."
+    :accessor eglot--saved-initargs)
+   (inferior-process
+    :documentation "Server subprocess started automatically."
+    :accessor eglot--inferior-process))
+  :documentation
+  "Represents a server. Wraps a process for LSP communication.")
+
+(cl-defmethod initialize-instance :before ((_server eglot-lsp-server) &optional args)
+  (cl-remf args :initializationOptions))
+
+
+;;; Process management
+(defvar eglot--servers-by-project (make-hash-table :test #'equal)
+  "Keys are projects.  Values are lists of processes.")
+
+(defun eglot-shutdown (server &optional _interactive timeout preserve-buffers)
+  "Politely ask SERVER to quit.
+Interactively, read SERVER from the minibuffer unless there is
+only one and it's managing the current buffer.
+
+Forcefully quit it if it doesn't respond within TIMEOUT seconds.
+TIMEOUT defaults to 1.5 seconds.  Don't leave this function with
+the server still running.
+
+If PRESERVE-BUFFERS is non-nil (interactively, when called with a
+prefix argument), do not kill events and output buffers of
+SERVER."
+  (interactive (list (eglot--read-server "Shutdown which server"
+                                         (eglot-current-server))
+                     t nil current-prefix-arg))
+  (eglot--message "Asking %s politely to terminate" (jsonrpc-name server))
+  (unwind-protect
+      (progn
+        (setf (eglot--shutdown-requested server) t)
+        (jsonrpc-request server :shutdown nil :timeout (or timeout 1.5))
+        (jsonrpc-notify server :exit nil))
+    ;; Now ask jsonrpc.el to shut down the server.
+    (jsonrpc-shutdown server (not preserve-buffers))
+    (unless preserve-buffers (kill-buffer (jsonrpc-events-buffer server)))))
+
+(defun eglot-shutdown-all (&optional preserve-buffers)
+  "Politely ask all language servers to quit, in order.
+PRESERVE-BUFFERS as in `eglot-shutdown', which see."
+  (interactive (list current-prefix-arg))
+  (cl-loop for ss being the hash-values of eglot--servers-by-project
+           do (cl-loop for s in ss do (eglot-shutdown s nil preserve-buffers))))
+
+(defun eglot--on-shutdown (server)
+  "Called by jsonrpc.el when SERVER is already dead."
+  ;; Turn off `eglot--managed-mode' where appropriate.
+  (dolist (buffer (eglot--managed-buffers server))
+    (let (;; Avoid duplicate shutdowns (github#389)
+          (eglot-autoshutdown nil))
+      (eglot--when-live-buffer buffer (eglot--managed-mode-off))))
+  ;; Kill any expensive watches
+  (maphash (lambda (_id watches)
+             (mapcar #'file-notify-rm-watch watches))
+           (eglot--file-watches server))
+  ;; Kill any autostarted inferior processes
+  (when-let (proc (eglot--inferior-process server))
+    (delete-process proc))
+  ;; Sever the project/server relationship for `server'
+  (setf (gethash (eglot--project server) eglot--servers-by-project)
+        (delq server
+              (gethash (eglot--project server) eglot--servers-by-project)))
+  (cond ((eglot--shutdown-requested server)
+         t)
+        ((not (eglot--inhibit-autoreconnect server))
+         (eglot--warn "Reconnecting after unexpected server exit.")
+         (eglot-reconnect server))
+        ((timerp (eglot--inhibit-autoreconnect server))
+         (eglot--warn "Not auto-reconnecting, last one didn't last long."))))
+
+(defun eglot--all-major-modes ()
+  "Return all known major modes."
+  (let ((retval))
+    (mapatoms (lambda (sym)
+                (when (plist-member (symbol-plist sym) 'derived-mode-parent)
+                  (push sym retval))))
+    retval))
+
+(defvar eglot--command-history nil
+  "History of CONTACT arguments to `eglot'.")
+
+(defun eglot--lookup-mode (mode)
+  "Lookup `eglot-server-programs' for MODE.
+Return (MANAGED-MODES LANGUAGE-ID CONTACT-PROXY).
+
+MANAGED-MODES is a list with MODE as its first elements.
+Subsequent elements are other major modes also potentially
+managed by the server that is to manage MODE.
+
+If not specified in `eglot-server-programs' (which see),
+LANGUAGE-ID is determined from MODE's name.
+
+CONTACT-PROXY is the value of the corresponding
+`eglot-server-programs' entry."
+  (cl-loop
+   for (modes . contact) in eglot-server-programs
+   for mode-symbols = (cons mode
+                            (delete mode
+                                    (mapcar #'car
+                                            (mapcar #'eglot--ensure-list
+                                                    (eglot--ensure-list modes)))))
+   thereis (cl-some
+            (lambda (spec)
+              (cl-destructuring-bind (probe &key language-id &allow-other-keys)
+                  (eglot--ensure-list spec)
+                (and (provided-mode-derived-p mode probe)
+                     (list
+                      mode-symbols
+                      (or language-id
+                          (or (get mode 'eglot-language-id)
+                              (get spec 'eglot-language-id)
+                              (string-remove-suffix "-mode" (symbol-name mode))))
+                      contact))))
+            (if (or (symbolp modes) (keywordp (cadr modes)))
+                (list modes) modes))))
+
+(defun eglot--guess-contact (&optional interactive)
+  "Helper for `eglot'.
+Return (MANAGED-MODE PROJECT CLASS CONTACT LANG-ID).  If INTERACTIVE is
+non-nil, maybe prompt user, else error as soon as something can't
+be guessed."
+  (let* ((guessed-mode (if buffer-file-name major-mode))
+         (main-mode
+          (cond
+           ((and interactive
+                 (or (>= (prefix-numeric-value current-prefix-arg) 16)
+                     (not guessed-mode)))
+            (intern
+             (completing-read
+              "[eglot] Start a server to manage buffers of what major mode? "
+              (mapcar #'symbol-name (eglot--all-major-modes)) nil t
+              (symbol-name guessed-mode) nil (symbol-name guessed-mode) nil)))
+           ((not guessed-mode)
+            (eglot--error "Can't guess mode to manage for `%s'" (current-buffer)))
+           (t guessed-mode)))
+         (triplet (eglot--lookup-mode main-mode))
+         (managed-modes (car triplet))
+         (language-id (or (cadr triplet)
+                          (string-remove-suffix "-mode" (symbol-name guessed-mode))))
+         (guess (caddr triplet))
+         (guess (if (functionp guess)
+                    (funcall guess interactive)
+                  guess))
+         (class (or (and (consp guess) (symbolp (car guess))
+                         (prog1 (unless current-prefix-arg (car guess))
+                           (setq guess (cdr guess))))
+                    'eglot-lsp-server))
+         (program (and (listp guess)
+                       (stringp (car guess))
+                       ;; A second element might be the port of a (host, port)
+                       ;; pair, but in that case it is not a string.
+                       (or (null (cdr guess)) (stringp (cadr guess)))
+                       (car guess)))
+         (base-prompt
+          (and interactive
+               "Enter program to execute (or <host>:<port>): "))
+         (full-program-invocation
+          (and program
+               (cl-every #'stringp guess)
+               (combine-and-quote-strings guess)))
+         (prompt
+          (and base-prompt
+               (cond (current-prefix-arg base-prompt)
+                     ((null guess)
+                      (format "[eglot] Sorry, couldn't guess for `%s'!\n%s"
+                              main-mode base-prompt))
+                     ((and program
+                           (not (file-name-absolute-p program))
+                           (not (eglot--executable-find program t)))
+                      (if full-program-invocation
+                          (concat (format "[eglot] I guess you want to run `%s'"
+                                          full-program-invocation)
+                                  (format ", but I can't find `%s' in PATH!"
+                                          program)
+                                  "\n" base-prompt)
+                        (eglot--error
+                         (concat "`%s' not found in PATH, but can't form"
+                                 " an interactive prompt for to fix %s!")
+                         program guess))))))
+         (contact
+          (or (and prompt
+                   (split-string-and-unquote
+                    (read-shell-command
+                     prompt
+                     full-program-invocation
+                     'eglot-command-history)))
+              guess)))
+    (list managed-modes (eglot--current-project) class contact language-id)))
+
+(defvar eglot-lsp-context)
+(put 'eglot-lsp-context 'variable-documentation
+     "Dynamically non-nil when searching for projects in LSP context.")
+
+(defvar eglot--servers-by-xrefed-file
+  (make-hash-table :test 'equal :weakness 'value))
+
+(defun eglot--current-project ()
+  "Return a project object for Eglot's LSP purposes.
+This relies on `project-current' and thus on
+`project-find-functions'.  Functions in the latter
+variable (which see) can query the value `eglot-lsp-context' to
+decide whether a given directory is a project containing a
+suitable root directory for a given LSP server's purposes."
+  (let ((eglot-lsp-context t))
+    (or (project-current) `(transient . ,default-directory))))
+
+;;;###autoload
+(defun eglot (managed-major-mode project class contact language-id
+                                 &optional interactive)
+  "Manage a project with a Language Server Protocol (LSP) server.
+
+The LSP server of CLASS is started (or contacted) via CONTACT.
+If this operation is successful, current *and future* file
+buffers of MANAGED-MAJOR-MODE inside PROJECT become \"managed\"
+by the LSP server, meaning information about their contents is
+exchanged periodically to provide enhanced code-analysis via
+`xref-find-definitions', `flymake-mode', `eldoc-mode',
+`completion-at-point', among others.
+
+Interactively, the command attempts to guess MANAGED-MAJOR-MODE
+from current buffer, CLASS and CONTACT from
+`eglot-server-programs' and PROJECT from
+`project-find-functions'.  The search for active projects in this
+context binds `eglot-lsp-context' (which see).
+
+If it can't guess, the user is prompted.  With a single
+\\[universal-argument] prefix arg, it always prompt for COMMAND.
+With two \\[universal-argument] prefix args, also prompts for
+MANAGED-MAJOR-MODE.
+
+PROJECT is a project object as returned by `project-current'.
+
+CLASS is a subclass of `eglot-lsp-server'.
+
+CONTACT specifies how to contact the server.  It is a
+keyword-value plist used to initialize CLASS or a plain list as
+described in `eglot-server-programs', which see.
+
+LANGUAGE-ID is the language ID string to send to the server for
+MANAGED-MAJOR-MODE, which matters to a minority of servers.
+
+INTERACTIVE is t if called interactively."
+  (interactive (append (eglot--guess-contact t) '(t)))
+  (let* ((current-server (eglot-current-server))
+         (live-p (and current-server (jsonrpc-running-p current-server))))
+    (if (and live-p
+             interactive
+             (y-or-n-p "[eglot] Live process found, reconnect instead? "))
+        (eglot-reconnect current-server interactive)
+      (when live-p (ignore-errors (eglot-shutdown current-server)))
+      (eglot--connect managed-major-mode project class contact language-id))))
+
+(defun eglot-reconnect (server &optional interactive)
+  "Reconnect to SERVER.
+INTERACTIVE is t if called interactively."
+  (interactive (list (eglot--current-server-or-lose) t))
+  (when (jsonrpc-running-p server)
+    (ignore-errors (eglot-shutdown server interactive nil 'preserve-buffers)))
+  (eglot--connect (eglot--major-modes server)
+                  (eglot--project server)
+                  (eieio-object-class-name server)
+                  (eglot--saved-initargs server)
+                  (eglot--language-id server))
+  (eglot--message "Reconnected!"))
+
+(defvar eglot--managed-mode) ; forward decl
+
+;;;###autoload
+(defun eglot-ensure ()
+  "Start Eglot session for current buffer if there isn't one."
+  (let ((buffer (current-buffer)))
+    (cl-labels
+        ((maybe-connect
+          ()
+          (remove-hook 'post-command-hook #'maybe-connect nil)
+          (eglot--when-live-buffer buffer
+            (unless eglot--managed-mode
+              (apply #'eglot--connect (eglot--guess-contact))))))
+      (when buffer-file-name
+        (add-hook 'post-command-hook #'maybe-connect 'append nil)))))
+
+(defun eglot-events-buffer (server)
+  "Display events buffer for SERVER.
+Use current server's or first available Eglot events buffer."
+  (interactive (list (eglot-current-server)))
+  (let ((buffer (if server (jsonrpc-events-buffer server)
+                  (cl-find "\\*EGLOT.*events\\*"
+                           (buffer-list)
+                           :key #'buffer-name :test #'string-match))))
+    (if buffer (display-buffer buffer)
+      (eglot--error "Can't find an Eglot events buffer!"))))
+
+(defun eglot-stderr-buffer (server)
+  "Display stderr buffer for SERVER."
+  (interactive (list (eglot--current-server-or-lose)))
+  (display-buffer (jsonrpc-stderr-buffer server)))
+
+(defun eglot-forget-pending-continuations (server)
+  "Forget pending requests for SERVER."
+  (interactive (list (eglot--current-server-or-lose)))
+  (jsonrpc-forget-pending-continuations server))
+
+(defvar eglot-connect-hook
+  '(eglot-signal-didChangeConfiguration)
+  "Hook run after connecting in `eglot--connect'.")
+
+(defvar eglot-server-initialized-hook
+  '()
+  "Hook run after a `eglot-lsp-server' instance is created.
+
+That is before a connection was established.  Use
+`eglot-connect-hook' to hook into when a connection was
+successfully established and the server on the other side has
+received the initializing configuration.
+
+Each function is passed the server as an argument")
+
+(defun eglot--cmd (contact)
+  "Helper for `eglot--connect'."
+  (if (file-remote-p default-directory)
+      ;; TODO: this seems like a bug, although it’s everywhere. For
+      ;; some reason, for remote connections only, over a pipe, we
+      ;; need to turn off line buffering on the tty.
+      ;;
+      ;; Not only does this seem like there should be a better way,
+      ;; but it almost certainly doesn’t work on non-unix systems.
+      (list "sh" "-c"
+            (string-join (cons "stty raw > /dev/null;"
+                               (mapcar #'shell-quote-argument contact))
+             " "))
+    contact))
+
+(defvar-local eglot--cached-server nil
+  "A cached reference to the current Eglot server.")
+
+(defun eglot--connect (managed-modes project class contact language-id)
+  "Connect to MANAGED-MODES, LANGUAGE-ID, PROJECT, CLASS and CONTACT.
+This docstring appeases checkdoc, that's all."
+  (let* ((default-directory (project-root project))
+         (nickname (file-name-base (directory-file-name default-directory)))
+         (readable-name (format "EGLOT (%s/%s)" nickname managed-modes))
+         autostart-inferior-process
+         server-info
+         (contact (if (functionp contact) (funcall contact) contact))
+         (initargs
+          (cond ((keywordp (car contact)) contact)
+                ((integerp (cadr contact))
+                 (setq server-info (list (format "%s:%s" (car contact)
+                                                 (cadr contact))))
+                 `(:process ,(lambda ()
+                               (apply #'open-network-stream
+                                      readable-name nil
+                                      (car contact) (cadr contact)
+                                      (cddr contact)))))
+                ((and (stringp (car contact)) (memq :autoport contact))
+                 (setq server-info (list "<inferior process>"))
+                 `(:process ,(lambda ()
+                               (pcase-let ((`(,connection . ,inferior)
+                                            (eglot--inferior-bootstrap
+                                             readable-name
+                                             contact)))
+                                 (setq autostart-inferior-process inferior)
+                                 connection))))
+                ((stringp (car contact))
+                 (let* ((probe (cl-position-if #'keywordp contact))
+                        (more-initargs (and probe (cl-subseq contact probe)))
+                        (contact (cl-subseq contact 0 probe)))
+                   `(:process
+                     ,(lambda ()
+                        (let ((default-directory default-directory))
+                          (make-process
+                           :name readable-name
+                           :command (setq server-info (eglot--cmd contact))
+                           :connection-type 'pipe
+                           :coding 'utf-8-emacs-unix
+                           :noquery t
+                           :stderr (get-buffer-create
+                                    (format "*%s stderr*" readable-name))
+                           :file-handler t)))
+                     ,@more-initargs)))))
+         (spread (lambda (fn) (lambda (server method params)
+                                (let ((eglot--cached-server server))
+                                 (apply fn server method (append params nil))))))
+         (server
+          (apply
+           #'make-instance class
+           :name readable-name
+           :events-buffer-scrollback-size eglot-events-buffer-size
+           :notification-dispatcher (funcall spread #'eglot-handle-notification)
+           :request-dispatcher (funcall spread #'eglot-handle-request)
+           :on-shutdown #'eglot--on-shutdown
+           initargs))
+         (cancelled nil)
+         (tag (make-symbol "connected-catch-tag")))
+    (when server-info
+      (jsonrpc--debug server "Running language server: %s"
+                      (string-join server-info " ")))
+    (setf (eglot--saved-initargs server) initargs)
+    (setf (eglot--project server) project)
+    (setf (eglot--project-nickname server) nickname)
+    (setf (eglot--major-modes server) (eglot--ensure-list managed-modes))
+    (setf (eglot--language-id server) language-id)
+    (setf (eglot--inferior-process server) autostart-inferior-process)
+    (run-hook-with-args 'eglot-server-initialized-hook server)
+    ;; Now start the handshake.  To honour `eglot-sync-connect'
+    ;; maybe-sync-maybe-async semantics we use `jsonrpc-async-request'
+    ;; and mimic most of `jsonrpc-request'.
+    (unwind-protect
+        (condition-case _quit
+            (let ((retval
+                   (catch tag
+                     (jsonrpc-async-request
+                      server
+                      :initialize
+                      (list :processId
+                            (unless (or eglot-withhold-process-id
+                                        (file-remote-p default-directory)
+                                        (eq (jsonrpc-process-type server)
+                                            'network))
+                              (emacs-pid))
+                            ;; Maybe turn trampy `/ssh:foo@bar:/path/to/baz.py'
+                            ;; into `/path/to/baz.py', so LSP groks it.
+                            :rootPath (file-local-name
+                                       (expand-file-name default-directory))
+                            :rootUri (eglot--path-to-uri default-directory)
+                            :initializationOptions (eglot-initialization-options
+                                                    server)
+                            :capabilities (eglot-client-capabilities server)
+                            :workspaceFolders (eglot-workspace-folders server))
+                      :success-fn
+                      (eglot--lambda ((InitializeResult) capabilities serverInfo)
+                        (unless cancelled
+                          (push server
+                                (gethash project eglot--servers-by-project))
+                          (setf (eglot--capabilities server) capabilities)
+                          (setf (eglot--server-info server) serverInfo)
+                          (jsonrpc-notify server :initialized eglot--{})
+                          (dolist (buffer (buffer-list))
+                            (with-current-buffer buffer
+                              ;; No need to pass SERVER as an argument: it has
+                              ;; been registered in `eglot--servers-by-project',
+                              ;; so that it can be found (and cached) from
+                              ;; `eglot--maybe-activate-editing-mode' in any
+                              ;; managed buffer.
+                              (eglot--maybe-activate-editing-mode)))
+                          (setf (eglot--inhibit-autoreconnect server)
+                                (cond
+                                 ((booleanp eglot-autoreconnect)
+                                  (not eglot-autoreconnect))
+                                 ((cl-plusp eglot-autoreconnect)
+                                  (run-with-timer
+                                   eglot-autoreconnect nil
+                                   (lambda ()
+                                     (setf (eglot--inhibit-autoreconnect server)
+                                           (null eglot-autoreconnect)))))))
+                          (let ((default-directory (project-root project))
+                                (major-mode (car managed-modes)))
+                            (hack-dir-local-variables-non-file-buffer)
+                            (run-hook-with-args 'eglot-connect-hook server))
+                          (eglot--message
+                           "Connected! Server `%s' now managing `%s' buffers \
+in project `%s'."
+                           (or (plist-get serverInfo :name)
+                               (jsonrpc-name server))
+                           managed-modes
+                           (eglot-project-nickname server))
+                          (when tag (throw tag t))))
+                      :timeout eglot-connect-timeout
+                      :error-fn (eglot--lambda ((ResponseError) code message)
+                                  (unless cancelled
+                                    (jsonrpc-shutdown server)
+                                    (let ((msg (format "%s: %s" code message)))
+                                      (if tag (throw tag `(error . ,msg))
+                                        (eglot--error msg)))))
+                      :timeout-fn (lambda ()
+                                    (unless cancelled
+                                      (jsonrpc-shutdown server)
+                                      (let ((msg (format "Timed out after %s seconds"
+                                                         eglot-connect-timeout)))
+                                        (if tag (throw tag `(error . ,msg))
+                                          (eglot--error msg))))))
+                     (cond ((numberp eglot-sync-connect)
+                            (accept-process-output nil eglot-sync-connect))
+                           (eglot-sync-connect
+                            (while t (accept-process-output
+                                      nil eglot-connect-timeout)))))))
+              (pcase retval
+                (`(error . ,msg) (eglot--error msg))
+                (`nil (eglot--message "Waiting in background for server `%s'"
+                                      (jsonrpc-name server))
+                      nil)
+                (_ server)))
+          (quit (jsonrpc-shutdown server) (setq cancelled 'quit)))
+      (setq tag nil))))
+
+(defun eglot--inferior-bootstrap (name contact &optional connect-args)
+  "Use CONTACT to start a server, then connect to it.
+Return a cons of two process objects (CONNECTION . INFERIOR).
+Name both based on NAME.
+CONNECT-ARGS are passed as additional arguments to
+`open-network-stream'."
+  (let* ((port-probe (make-network-process :name "eglot-port-probe-dummy"
+                                           :server t
+                                           :host "localhost"
+                                           :service 0))
+         (port-number (unwind-protect
+                          (process-contact port-probe :service)
+                        (delete-process port-probe)))
+         inferior connection)
+    (unwind-protect
+        (progn
+          (setq inferior
+                (make-process
+                 :name (format "autostart-inferior-%s" name)
+                 :stderr (format "*%s stderr*" name)
+                 :noquery t
+                 :command (cl-subst
+                           (format "%s" port-number) :autoport contact)))
+          (setq connection
+                (cl-loop
+                 repeat 10 for i from 1
+                 do (accept-process-output nil 0.5)
+                 while (process-live-p inferior)
+                 do (eglot--message
+                     "Trying to connect to localhost and port %s (attempt %s)"
+                     port-number i)
+                 thereis (ignore-errors
+                           (apply #'open-network-stream
+                                  (format "autoconnect-%s" name)
+                                  nil
+                                  "localhost" port-number connect-args))))
+          (cons connection inferior))
+      (cond ((and (process-live-p connection)
+                  (process-live-p inferior))
+             (eglot--message "Done, connected to %s!" port-number))
+            (t
+             (when inferior (delete-process inferior))
+             (when connection (delete-process connection))
+             (eglot--error "Could not start and connect to server%s"
+                           (if inferior
+                               (format " started with %s"
+                                       (process-command inferior))
+                             "!")))))))
+
+
+;;; Helpers (move these to API?)
+;;;
+(defun eglot--error (format &rest args)
+  "Error out with FORMAT with ARGS."
+  (error "[eglot] %s" (apply #'format format args)))
+
+(defun eglot--message (format &rest args)
+  "Message out with FORMAT with ARGS."
+  (message "[eglot] %s" (apply #'format format args)))
+
+(defun eglot--warn (format &rest args)
+  "Warning message with FORMAT and ARGS."
+  (apply #'eglot--message (concat "(warning) " format) args)
+  (let ((warning-minimum-level :error))
+    (display-warning 'eglot (apply #'format format args) :warning)))
+
+(defun eglot-current-column () (- (point) (line-beginning-position)))
+
+(defvar eglot-current-column-function #'eglot-lsp-abiding-column
+  "Function to calculate the current column.
+
+This is the inverse operation of
+`eglot-move-to-column-function' (which see).  It is a function of
+no arguments returning a column number.  For buffers managed by
+fully LSP-compliant servers, this should be set to
+`eglot-lsp-abiding-column' (the default), and
+`eglot-current-column' for all others.")
+
+(defun eglot-lsp-abiding-column (&optional lbp)
+  "Calculate current COLUMN as defined by the LSP spec.
+LBP defaults to `line-beginning-position'."
+  (/ (- (length (encode-coding-region (or lbp (line-beginning-position))
+                                      ;; Fix github#860
+                                      (min (point) (point-max)) 'utf-16 t))
+        2)
+     2))
+
+(defun eglot--pos-to-lsp-position (&optional pos)
+  "Convert point POS to LSP position."
+  (eglot--widening
+   (list :line (1- (line-number-at-pos pos t)) ; F!@&#$CKING OFF-BY-ONE
+         :character (progn (when pos (goto-char pos))
+                           (funcall eglot-current-column-function)))))
+
+(defvar eglot-move-to-column-function #'eglot-move-to-lsp-abiding-column
+  "Function to move to a column reported by the LSP server.
+
+According to the standard, LSP column/character offsets are based
+on a count of UTF-16 code units, not actual visual columns.  So
+when LSP says position 3 of a line containing just \"aXbc\",
+where X is a multi-byte character, it actually means `b', not
+`c'. However, many servers don't follow the spec this closely.
+
+For buffers managed by fully LSP-compliant servers, this should
+be set to `eglot-move-to-lsp-abiding-column' (the default), and
+`eglot-move-to-column' for all others.")
+
+(defun eglot-move-to-column (column)
+  "Move to COLUMN without closely following the LSP spec."
+  ;; We cannot use `move-to-column' here, because it moves to *visual*
+  ;; columns, which can be different from LSP columns in case of
+  ;; `whitespace-mode', `prettify-symbols-mode', etc.  (github#296,
+  ;; github#297)
+  (goto-char (min (+ (line-beginning-position) column)
+                  (line-end-position))))
+
+(defun eglot-move-to-lsp-abiding-column (column)
+  "Move to COLUMN abiding by the LSP spec."
+  (save-restriction
+    (cl-loop
+     with lbp = (line-beginning-position)
+     initially
+     (narrow-to-region lbp (line-end-position))
+     (move-to-column column)
+     for diff = (- column
+                   (eglot-lsp-abiding-column lbp))
+     until (zerop diff)
+     do (condition-case eob-err
+            (forward-char (/ (if (> diff 0) (1+ diff) (1- diff)) 2))
+          (end-of-buffer (cl-return eob-err))))))
+
+(defun eglot--lsp-position-to-point (pos-plist &optional marker)
+  "Convert LSP position POS-PLIST to Emacs point.
+If optional MARKER, return a marker instead"
+  (save-excursion
+    (save-restriction
+      (widen)
+      (goto-char (point-min))
+      (forward-line (min most-positive-fixnum
+                         (plist-get pos-plist :line)))
+      (unless (eobp) ;; if line was excessive leave point at eob
+        (let ((tab-width 1)
+              (col (plist-get pos-plist :character)))
+          (unless (wholenump col)
+            (eglot--warn
+             "Caution: LSP server sent invalid character position %s. Using 0 instead."
+             col)
+            (setq col 0))
+          (funcall eglot-move-to-column-function col)))
+      (if marker (copy-marker (point-marker)) (point)))))
+
+(defconst eglot--uri-path-allowed-chars
+  (let ((vec (copy-sequence url-path-allowed-chars)))
+    (aset vec ?: nil) ;; see github#639
+    vec)
+  "Like `url-path-allows-chars' but more restrictive.")
+
+(defun eglot--path-to-uri (path)
+  "URIfy PATH."
+  (let ((truepath (file-truename path)))
+    (concat "file://"
+            ;; Add a leading "/" for local MS Windows-style paths.
+            (if (and (eq system-type 'windows-nt)
+                     (not (file-remote-p truepath)))
+                "/")
+            (url-hexify-string
+             ;; Again watch out for trampy paths.
+             (directory-file-name (file-local-name truepath))
+             eglot--uri-path-allowed-chars))))
+
+(defun eglot--uri-to-path (uri)
+  "Convert URI to file path, helped by `eglot--current-server'."
+  (when (keywordp uri) (setq uri (substring (symbol-name uri) 1)))
+  (let* ((server (eglot-current-server))
+         (remote-prefix (and server (eglot--trampish-p server)))
+         (retval (url-unhex-string (url-filename (url-generic-parse-url uri))))
+         ;; Remove the leading "/" for local MS Windows-style paths.
+         (normalized (if (and (not remote-prefix)
+                              (eq system-type 'windows-nt)
+                              (cl-plusp (length retval)))
+                         (substring retval 1)
+                       retval)))
+    (concat remote-prefix normalized)))
+
+(defun eglot--snippet-expansion-fn ()
+  "Compute a function to expand snippets.
+Doubles as an indicator of snippet support."
+  (and (boundp 'yas-minor-mode)
+       (symbol-value 'yas-minor-mode)
+       'yas-expand-snippet))
+
+(defun eglot--format-markup (markup)
+  "Format MARKUP according to LSP's spec."
+  (pcase-let ((`(,string ,mode)
+               (if (stringp markup) (list markup 'gfm-view-mode)
+                 (list (plist-get markup :value)
+                       (pcase (plist-get markup :kind)
+                         ("markdown" 'gfm-view-mode)
+                         ("plaintext" 'text-mode)
+                         (_ major-mode))))))
+    (with-temp-buffer
+      (setq-local markdown-fontify-code-blocks-natively t)
+      (insert string)
+      (let ((inhibit-message t)
+            (message-log-max nil))
+        (ignore-errors (delay-mode-hooks (funcall mode))))
+      (font-lock-ensure)
+      (string-trim (buffer-string)))))
+
+(define-obsolete-variable-alias 'eglot-ignored-server-capabilites
+  'eglot-ignored-server-capabilities "1.8")
+
+(defcustom eglot-ignored-server-capabilities (list)
+  "LSP server capabilities that Eglot could use, but won't.
+You could add, for instance, the symbol
+`:documentHighlightProvider' to prevent automatic highlighting
+under cursor."
+  :type '(set
+          :tag "Tick the ones you're not interested in"
+          (const :tag "Documentation on hover" :hoverProvider)
+          (const :tag "Code completion" :completionProvider)
+          (const :tag "Function signature help" :signatureHelpProvider)
+          (const :tag "Go to definition" :definitionProvider)
+          (const :tag "Go to type definition" :typeDefinitionProvider)
+          (const :tag "Go to implementation" :implementationProvider)
+          (const :tag "Go to declaration" :implementationProvider)
+          (const :tag "Find references" :referencesProvider)
+          (const :tag "Highlight symbols automatically" :documentHighlightProvider)
+          (const :tag "List symbols in buffer" :documentSymbolProvider)
+          (const :tag "List symbols in workspace" :workspaceSymbolProvider)
+          (const :tag "Execute code actions" :codeActionProvider)
+          (const :tag "Code lens" :codeLensProvider)
+          (const :tag "Format buffer" :documentFormattingProvider)
+          (const :tag "Format portion of buffer" :documentRangeFormattingProvider)
+          (const :tag "On-type formatting" :documentOnTypeFormattingProvider)
+          (const :tag "Rename symbol" :renameProvider)
+          (const :tag "Highlight links in document" :documentLinkProvider)
+          (const :tag "Decorate color references" :colorProvider)
+          (const :tag "Fold regions of buffer" :foldingRangeProvider)
+          (const :tag "Execute custom commands" :executeCommandProvider)))
+
+(defun eglot--server-capable (&rest feats)
+  "Determine if current server is capable of FEATS."
+  (unless (cl-some (lambda (feat)
+                     (memq feat eglot-ignored-server-capabilities))
+                   feats)
+    (cl-loop for caps = (eglot--capabilities (eglot--current-server-or-lose))
+             then (cadr probe)
+             for (feat . more) on feats
+             for probe = (plist-member caps feat)
+             if (not probe) do (cl-return nil)
+             if (eq (cadr probe) :json-false) do (cl-return nil)
+             if (not (listp (cadr probe))) do (cl-return (if more nil (cadr probe)))
+             finally (cl-return (or (cadr probe) t)))))
+
+(defun eglot--range-region (range &optional markers)
+  "Return region (BEG . END) that represents LSP RANGE.
+If optional MARKERS, make markers."
+  (let* ((st (plist-get range :start))
+         (beg (eglot--lsp-position-to-point st markers))
+         (end (eglot--lsp-position-to-point (plist-get range :end) markers)))
+    (cons beg end)))
+
+(defun eglot--read-server (prompt &optional dont-if-just-the-one)
+  "Read a running Eglot server from minibuffer using PROMPT.
+If DONT-IF-JUST-THE-ONE and there's only one server, don't prompt
+and just return it.  PROMPT shouldn't end with a question mark."
+  (let ((servers (cl-loop for servers
+                          being hash-values of eglot--servers-by-project
+                          append servers))
+        (name (lambda (srv)
+                (format "%s %s" (eglot-project-nickname srv)
+                        (eglot--major-modes srv)))))
+    (cond ((null servers)
+           (eglot--error "No servers!"))
+          ((or (cdr servers) (not dont-if-just-the-one))
+           (let* ((default (when-let ((current (eglot-current-server)))
+                             (funcall name current)))
+                  (read (completing-read
+                         (if default
+                             (format "%s (default %s)? " prompt default)
+                           (concat prompt "? "))
+                         (mapcar name servers)
+                         nil t
+                         nil nil
+                         default)))
+             (cl-find read servers :key name :test #'equal)))
+          (t (car servers)))))
+
+(defun eglot--trampish-p (server)
+  "Tell if SERVER's project root is `file-remote-p'."
+  (file-remote-p (project-root (eglot--project server))))
+
+(defun eglot--plist-keys (plist) "Get keys of a plist."
+  (cl-loop for (k _v) on plist by #'cddr collect k))
+
+(defun eglot--ensure-list (x) (if (listp x) x (list x)))
+
+
+;;; Minor modes
+;;;
+(defvar eglot-mode-map
+  (let ((map (make-sparse-keymap)))
+    (define-key map [remap display-local-help] #'eldoc-doc-buffer)
+    map))
+
+(defvar-local eglot--current-flymake-report-fn nil
+  "Current flymake report function for this buffer.")
+
+(defvar-local eglot--saved-bindings nil
+  "Bindings saved by `eglot--setq-saving'.")
+
+(defvar eglot-stay-out-of '()
+  "List of Emacs things that Eglot should try to stay of.
+Each element is a string, a symbol, or a regexp which is matched
+against a variable's name.  Examples include the string
+\"company\" or the symbol `xref'.
+
+Before Eglot starts \"managing\" a particular buffer, it
+opinionatedly sets some peripheral Emacs facilities, such as
+Flymake, Xref and Company.  These overriding settings help ensure
+consistent Eglot behaviour and only stay in place until
+\"managing\" stops (usually via `eglot-shutdown'), whereupon the
+previous settings are restored.
+
+However, if you wish for Eglot to stay out of a particular Emacs
+facility that you'd like to keep control of add an element to
+this list and Eglot will refrain from setting it.
+
+For example, to keep your Company customization, add the symbol
+`company' to this variable.")
+
+(defun eglot--stay-out-of-p (symbol)
+  "Tell if Eglot should stay of of SYMBOL."
+  (cl-find (symbol-name symbol) eglot-stay-out-of
+           :test (lambda (s thing)
+                   (let ((re (if (symbolp thing) (symbol-name thing) thing)))
+                     (string-match re s)))))
+
+(defmacro eglot--setq-saving (symbol binding)
+  `(unless (or (not (boundp ',symbol)) (eglot--stay-out-of-p ',symbol))
+     (push (cons ',symbol (symbol-value ',symbol)) eglot--saved-bindings)
+     (setq-local ,symbol ,binding)))
+
+(defun eglot-managed-p ()
+  "Tell if current buffer is managed by Eglot."
+  eglot--managed-mode)
+
+(defvar eglot-managed-mode-hook nil
+  "A hook run by Eglot after it started/stopped managing a buffer.
+Use `eglot-managed-p' to determine if current buffer is managed.")
+
+(define-minor-mode eglot--managed-mode
+  "Mode for source buffers managed by some Eglot project."
+  :init-value nil :lighter nil :keymap eglot-mode-map
+  (cond
+   (eglot--managed-mode
+    (add-hook 'after-change-functions 'eglot--after-change nil t)
+    (add-hook 'before-change-functions 'eglot--before-change nil t)
+    (add-hook 'kill-buffer-hook #'eglot--managed-mode-off nil t)
+    ;; Prepend "didClose" to the hook after the "nonoff", so it will run first
+    (add-hook 'kill-buffer-hook 'eglot--signal-textDocument/didClose nil t)
+    (add-hook 'before-revert-hook 'eglot--signal-textDocument/didClose nil t)
+    (add-hook 'after-revert-hook 'eglot--after-revert-hook nil t)
+    (add-hook 'before-save-hook 'eglot--signal-textDocument/willSave nil t)
+    (add-hook 'after-save-hook 'eglot--signal-textDocument/didSave nil t)
+    (unless (eglot--stay-out-of-p 'xref)
+      (add-hook 'xref-backend-functions 'eglot-xref-backend nil t))
+    (add-hook 'completion-at-point-functions #'eglot-completion-at-point nil t)
+    (add-hook 'change-major-mode-hook #'eglot--managed-mode-off nil t)
+    (add-hook 'post-self-insert-hook 'eglot--post-self-insert-hook nil t)
+    (add-hook 'pre-command-hook 'eglot--pre-command-hook nil t)
+    (eglot--setq-saving eldoc-documentation-functions
+                        '(eglot-signature-eldoc-function
+                          eglot-hover-eldoc-function))
+    (eglot--setq-saving eldoc-documentation-strategy
+                        #'eldoc-documentation-enthusiast)
+    (eglot--setq-saving xref-prompt-for-identifier nil)
+    (eglot--setq-saving flymake-diagnostic-functions '(eglot-flymake-backend))
+    (eglot--setq-saving company-backends '(company-capf))
+    (eglot--setq-saving company-tooltip-align-annotations t)
+    (unless (eglot--stay-out-of-p 'imenu)
+      (add-function :before-until (local 'imenu-create-index-function)
+                    #'eglot-imenu))
+    (unless (eglot--stay-out-of-p 'flymake) (flymake-mode 1))
+    (unless (eglot--stay-out-of-p 'eldoc) (eldoc-mode 1))
+    (cl-pushnew (current-buffer) (eglot--managed-buffers (eglot-current-server))))
+   (t
+    (remove-hook 'after-change-functions 'eglot--after-change t)
+    (remove-hook 'before-change-functions 'eglot--before-change t)
+    (remove-hook 'kill-buffer-hook #'eglot--managed-mode-off t)
+    (remove-hook 'kill-buffer-hook 'eglot--signal-textDocument/didClose t)
+    (remove-hook 'before-revert-hook 'eglot--signal-textDocument/didClose t)
+    (remove-hook 'after-revert-hook 'eglot--after-revert-hook t)
+    (remove-hook 'before-save-hook 'eglot--signal-textDocument/willSave t)
+    (remove-hook 'after-save-hook 'eglot--signal-textDocument/didSave t)
+    (remove-hook 'xref-backend-functions 'eglot-xref-backend t)
+    (remove-hook 'completion-at-point-functions #'eglot-completion-at-point t)
+    (remove-hook 'change-major-mode-hook #'eglot--managed-mode-off t)
+    (remove-hook 'post-self-insert-hook 'eglot--post-self-insert-hook t)
+    (remove-hook 'pre-command-hook 'eglot--pre-command-hook t)
+    (cl-loop for (var . saved-binding) in eglot--saved-bindings
+             do (set (make-local-variable var) saved-binding))
+    (remove-function (local 'imenu-create-index-function) #'eglot-imenu)
+    (when eglot--current-flymake-report-fn
+      (eglot--report-to-flymake nil)
+      (setq eglot--current-flymake-report-fn nil))
+    (let ((server eglot--cached-server))
+      (setq eglot--cached-server nil)
+      (when server
+        (setf (eglot--managed-buffers server)
+              (delq (current-buffer) (eglot--managed-buffers server)))
+        (when (and eglot-autoshutdown
+                   (null (eglot--managed-buffers server)))
+          (eglot-shutdown server))))))
+  ;; Note: the public hook runs before the internal eglot--managed-mode-hook.
+  (run-hooks 'eglot-managed-mode-hook))
+
+(defun eglot--managed-mode-off ()
+  "Turn off `eglot--managed-mode' unconditionally."
+  (eglot--managed-mode -1))
+
+(defun eglot-current-server ()
+  "Return logical Eglot server for current buffer, nil if none."
+  (setq eglot--cached-server
+        (or eglot--cached-server
+            (cl-find major-mode
+                     (gethash (eglot--current-project) eglot--servers-by-project)
+                     :key #'eglot--major-modes
+                     :test #'memq)
+            (and eglot-extend-to-xref
+                 buffer-file-name
+                 (gethash (expand-file-name buffer-file-name)
+                          eglot--servers-by-xrefed-file)))))
+
+(defun eglot--current-server-or-lose ()
+  "Return current logical Eglot server connection or error."
+  (or (eglot-current-server)
+      (jsonrpc-error "No current JSON-RPC connection")))
+
+(defvar-local eglot--diagnostics nil
+  "Flymake diagnostics for this buffer.")
+
+(defvar revert-buffer-preserve-modes)
+(defun eglot--after-revert-hook ()
+  "Eglot's `after-revert-hook'."
+  (when revert-buffer-preserve-modes (eglot--signal-textDocument/didOpen)))
+
+(defun eglot--maybe-activate-editing-mode ()
+  "Maybe activate `eglot--managed-mode'.
+
+If it is activated, also signal textDocument/didOpen."
+  (unless eglot--managed-mode
+    ;; Called when `revert-buffer-in-progress-p' is t but
+    ;; `revert-buffer-preserve-modes' is nil.
+    (when (and buffer-file-name (eglot-current-server))
+      (setq eglot--diagnostics nil)
+      (eglot--managed-mode)
+      (eglot--signal-textDocument/didOpen))))
+
+(add-hook 'find-file-hook 'eglot--maybe-activate-editing-mode)
+(add-hook 'after-change-major-mode-hook 'eglot--maybe-activate-editing-mode)
+
+(defun eglot-clear-status (server)
+  "Clear the last JSONRPC error for SERVER."
+  (interactive (list (eglot--current-server-or-lose)))
+  (setf (jsonrpc-last-error server) nil))
+
+
+;;; Mode-line, menu and other sugar
+;;;
+(defvar eglot--mode-line-format `(:eval (eglot--mode-line-format)))
+
+(put 'eglot--mode-line-format 'risky-local-variable t)
+
+(defun eglot--mouse-call (what)
+  "Make an interactive lambda for calling WHAT from mode-line."
+  (lambda (event)
+    (interactive "e")
+    (let ((start (event-start event))) (with-selected-window (posn-window start)
+                                         (save-excursion
+                                           (goto-char (or (posn-point start)
+                                                          (point)))
+                                           (call-interactively what)
+                                           (force-mode-line-update t))))))
+
+(defun eglot-manual () "Open on-line documentation."
+  (interactive) (browse-url "https://github.com/joaotavora/eglot#readme"))
+
+(easy-menu-define eglot-menu nil "Eglot"
+  `("Eglot"
+    ;; Commands for getting information and customization.
+    ["Read manual" eglot-manual]
+    ["Customize Eglot" (lambda () (interactive) (customize-group "eglot"))]
+    "--"
+    ;; xref like commands.
+    ["Find definitions" xref-find-definitions
+     :help "Find definitions of identifier at point"
+     :active (eglot--server-capable :definitionProvider)]
+    ["Find references" xref-find-references
+     :help "Find references to identifier at point"
+     :active (eglot--server-capable :referencesProvider)]
+    ["Find symbols in workspace (apropos)" xref-find-apropos
+     :help "Find symbols matching a query"
+     :active (eglot--server-capable :workspaceSymbolProvider)]
+    ["Find declaration" eglot-find-declaration
+     :help "Find declaration for identifier at point"
+     :active (eglot--server-capable :declarationProvider)]
+    ["Find implementation" eglot-find-implementation
+     :help "Find implementation for identifier at point"
+     :active (eglot--server-capable :implementationProvider)]
+    ["Find type definition" eglot-find-typeDefinition
+     :help "Find type definition for identifier at point"
+     :active (eglot--server-capable :typeDefinitionProvider)]
+    "--"
+    ;; LSP-related commands (mostly Eglot's own commands).
+    ["Rename symbol" eglot-rename
+     :active (eglot--server-capable :renameProvider)]
+    ["Format buffer" eglot-format-buffer
+     :active (eglot--server-capable :documentFormattingProvider)]
+    ["Format active region" eglot-format
+     :active (and (region-active-p)
+                  (eglot--server-capable :documentRangeFormattingProvider))]
+    ["Show Flymake diagnostics for buffer" flymake-show-buffer-diagnostics]
+    ["Show Flymake diagnostics for project" flymake-show-project-diagnostics]
+    ["Show Eldoc documentation at point" eldoc-doc-buffer]
+    "--"
+    ["All possible code actions" eglot-code-actions
+     :active (eglot--server-capable :codeActionProvider)]
+    ["Organize imports" eglot-code-action-organize-imports
+     :visible (eglot--server-capable :codeActionProvider)]
+    ["Extract" eglot-code-action-extract
+     :visible (eglot--server-capable :codeActionProvider)]
+    ["Inline" eglot-code-action-inline
+     :visible (eglot--server-capable :codeActionProvider)]
+    ["Rewrite" eglot-code-action-rewrite
+     :visible (eglot--server-capable :codeActionProvider)]
+    ["Quickfix" eglot-code-action-quickfix
+     :visible (eglot--server-capable :codeActionProvider)]))
+
+(easy-menu-define eglot-server-menu nil "Monitor server communication"
+  '("Debugging the server communication"
+    ["Reconnect to server" eglot-reconnect]
+    ["Quit server" eglot-shutdown]
+    "--"
+    ["LSP events buffer" eglot-events-buffer]
+    ["Server stderr buffer" eglot-stderr-buffer]
+    ["Customize event buffer size"
+     (lambda ()
+       (interactive)
+       (customize-variable 'eglot-events-buffer-size))]))
+
+(defun eglot--mode-line-props (thing face defs &optional prepend)
+  "Helper for function `eglot--mode-line-format'.
+Uses THING, FACE, DEFS and PREPEND."
+  (cl-loop with map = (make-sparse-keymap)
+           for (elem . rest) on defs
+           for (key def help) = elem
+           do (define-key map `[mode-line ,key] (eglot--mouse-call def))
+           concat (format "%s: %s" key help) into blurb
+           when rest concat "\n" into blurb
+           finally (return `(:propertize ,thing
+                                         face ,face
+                                         keymap ,map help-echo ,(concat prepend blurb)
+                                         mouse-face mode-line-highlight))))
+
+(defun eglot--mode-line-format ()
+  "Compose the Eglot's mode-line."
+  (pcase-let* ((server (eglot-current-server))
+               (nick (and server (eglot-project-nickname server)))
+               (pending (and server (hash-table-count
+                                     (jsonrpc--request-continuations server))))
+               (`(,_id ,doing ,done-p ,_detail) (and server (eglot--spinner server)))
+               (last-error (and server (jsonrpc-last-error server))))
+    (append
+     `(,(propertize
+         eglot-menu-string
+         'face 'eglot-mode-line
+         'mouse-face 'mode-line-highlight
+         'help-echo "Eglot: Emacs LSP client\nmouse-1: Display minor mode menu"
+         'keymap (let ((map (make-sparse-keymap)))
+                   (define-key map [mode-line down-mouse-1] eglot-menu)
+                   map)))
+     (when nick
+       `(":"
+         ,(propertize
+           nick
+           'face 'eglot-mode-line
+           'mouse-face 'mode-line-highlight
+           'help-echo (format "Project '%s'\nmouse-1: LSP server control menu" nick)
+           'keymap (let ((map (make-sparse-keymap)))
+                     (define-key map [mode-line down-mouse-1] eglot-server-menu)
+                     map))
+       ,@(when last-error
+             `("/" ,(eglot--mode-line-props
+                     "error" 'compilation-mode-line-fail
+                     '((mouse-3 eglot-clear-status  "Clear this status"))
+                     (format "An error occurred: %s\n" (plist-get last-error
+                                                                 :message)))))
+         ,@(when (and doing (not done-p))
+             `("/" ,(eglot--mode-line-props doing
+                                            'compilation-mode-line-run '())))
+         ,@(when (cl-plusp pending)
+             `("/" ,(eglot--mode-line-props
+                     (format "%d" pending) 'warning
+                     '((mouse-3 eglot-forget-pending-continuations
+                                "Forget pending continuations"))
+                     "Number of outgoing, \
+still unanswered LSP requests to the server\n"))))))))
+
+(add-to-list 'mode-line-misc-info
+             `(eglot--managed-mode (" [" eglot--mode-line-format "] ")))
+
+
+;;; Flymake customization
+;;;
+(put 'eglot-note 'flymake-category 'flymake-note)
+(put 'eglot-warning 'flymake-category 'flymake-warning)
+(put 'eglot-error 'flymake-category 'flymake-error)
+
+(defalias 'eglot--make-diag 'flymake-make-diagnostic)
+(defalias 'eglot--diag-data 'flymake-diagnostic-data)
+
+(cl-loop for i from 1
+         for type in '(eglot-note eglot-warning eglot-error )
+         do (put type 'flymake-overlay-control
+                 `((mouse-face . highlight)
+                   (priority . ,(+ 50 i))
+                   (keymap . ,(let ((map (make-sparse-keymap)))
+                                (define-key map [mouse-1]
+                                  (eglot--mouse-call 'eglot-code-actions))
+                                map)))))
+
+
+;;; Protocol implementation (Requests, notifications, etc)
+;;;
+(cl-defmethod eglot-handle-notification
+  (_server method &key &allow-other-keys)
+  "Handle unknown notification."
+  (unless (or (string-prefix-p "$" (format "%s" method))
+              (not (memq 'disallow-unknown-methods eglot-strict-mode)))
+    (eglot--warn "Server sent unknown notification method `%s'" method)))
+
+(cl-defmethod eglot-handle-request
+  (_server method &key &allow-other-keys)
+  "Handle unknown request."
+  (when (memq 'disallow-unknown-methods eglot-strict-mode)
+    (jsonrpc-error "Unknown request method `%s'" method)))
+
+(cl-defmethod eglot-execute-command
+  (server command arguments)
+  "Execute COMMAND on SERVER with `:workspace/executeCommand'.
+COMMAND is a symbol naming the command."
+  (jsonrpc-request server :workspace/executeCommand
+                   `(:command ,(format "%s" command) :arguments ,arguments)))
+
+(cl-defmethod eglot-handle-notification
+  (_server (_method (eql window/showMessage)) &key type message)
+  "Handle notification window/showMessage."
+  (eglot--message (propertize "Server reports (type=%s): %s"
+                              'face (if (<= type 1) 'error))
+                  type message))
+
+(cl-defmethod eglot-handle-request
+  (_server (_method (eql window/showMessageRequest)) &key type message actions)
+  "Handle server request window/showMessageRequest."
+  (let* ((actions (append actions nil)) ;; gh#627
+         (label (completing-read
+                 (concat
+                  (format (propertize "[eglot] Server reports (type=%s): %s"
+                                      'face (if (<= type 1) 'error))
+                          type message)
+                  "\nChoose an option: ")
+                 (or (mapcar (lambda (obj) (plist-get obj :title)) actions)
+                     '("OK"))
+                 nil t (plist-get (elt actions 0) :title))))
+    (if label `(:title ,label) :null)))
+
+(cl-defmethod eglot-handle-notification
+  (_server (_method (eql window/logMessage)) &key _type _message)
+  "Handle notification window/logMessage.") ;; noop, use events buffer
+
+(cl-defmethod eglot-handle-notification
+  (_server (_method (eql telemetry/event)) &rest _any)
+  "Handle notification telemetry/event.") ;; noop, use events buffer
+
+(cl-defmethod eglot-handle-notification
+  (_server (_method (eql textDocument/publishDiagnostics)) &key uri diagnostics
+           &allow-other-keys) ; FIXME: doesn't respect `eglot-strict-mode'
+  "Handle notification publishDiagnostics."
+  (cl-flet ((eglot--diag-type (sev)
+              (cond ((null sev) 'eglot-error)
+                    ((<= sev 1) 'eglot-error)
+                    ((= sev 2)  'eglot-warning)
+                    (t          'eglot-note)))
+            (mess (source code message)
+              (concat source (and code (format " [%s]" code)) ": " message)))
+    (if-let ((buffer (find-buffer-visiting (eglot--uri-to-path uri))))
+        (with-current-buffer buffer
+          (cl-loop
+           for diag-spec across diagnostics
+           collect (eglot--dbind ((Diagnostic) range code message severity source tags)
+                       diag-spec
+                     (setq message (mess source code message))
+                     (pcase-let
+                         ((`(,beg . ,end) (eglot--range-region range)))
+                       ;; Fallback to `flymake-diag-region' if server
+                       ;; botched the range
+                       (when (= beg end)
+                         (if-let* ((st (plist-get range :start))
+                                   (diag-region
+                                    (flymake-diag-region
+                                     (current-buffer) (1+ (plist-get st :line))
+                                     (plist-get st :character))))
+                             (setq beg (car diag-region) end (cdr diag-region))
+                           (eglot--widening
+                            (goto-char (point-min))
+                            (setq beg
+                                  (line-beginning-position
+                                   (1+ (plist-get (plist-get range :start) :line))))
+                            (setq end
+                                  (line-end-position
+                                   (1+ (plist-get (plist-get range :end) :line)))))))
+                       (eglot--make-diag
+                        (current-buffer) beg end
+                        (eglot--diag-type severity)
+                        message `((eglot-lsp-diag . ,diag-spec))
+                        (when-let ((faces
+                                    (cl-loop for tag across tags
+                                             when (alist-get tag eglot--tag-faces)
+                                             collect it)))
+                          `((face . ,faces))))))
+           into diags
+           finally (cond ((and
+                           ;; only add to current report if Flymake
+                           ;; starts on idle-timer (github#958)
+                           (not (null flymake-no-changes-timeout))
+                           eglot--current-flymake-report-fn)
+                          (eglot--report-to-flymake diags))
+                         (t
+                          (setq eglot--diagnostics diags)))))
+      (cl-loop
+       with path = (expand-file-name (eglot--uri-to-path uri))
+       for diag-spec across diagnostics
+       collect (eglot--dbind ((Diagnostic) code range message severity source) diag-spec
+                 (setq message (mess source code message))
+                 (let* ((start (plist-get range :start))
+                        (line (1+ (plist-get start :line)))
+                        (char (1+ (plist-get start :character))))
+                   (eglot--make-diag
+                    path (cons line char) nil (eglot--diag-type severity) message)))
+       into diags
+       finally
+       (setq flymake-list-only-diagnostics
+             (assoc-delete-all path flymake-list-only-diagnostics #'string=))
+       (push (cons path diags) flymake-list-only-diagnostics)))))
+
+(cl-defun eglot--register-unregister (server things how)
+  "Helper for `registerCapability'.
+THINGS are either registrations or unregisterations (sic)."
+  (cl-loop
+   for thing in (cl-coerce things 'list)
+   do (eglot--dbind ((Registration) id method registerOptions) thing
+        (apply (cl-ecase how
+                 (register 'eglot-register-capability)
+                 (unregister 'eglot-unregister-capability))
+               server (intern method) id registerOptions))))
+
+(cl-defmethod eglot-handle-request
+  (server (_method (eql client/registerCapability)) &key registrations)
+  "Handle server request client/registerCapability."
+  (eglot--register-unregister server registrations 'register))
+
+(cl-defmethod eglot-handle-request
+  (server (_method (eql client/unregisterCapability))
+          &key unregisterations) ;; XXX: "unregisterations" (sic)
+  "Handle server request client/unregisterCapability."
+  (eglot--register-unregister server unregisterations 'unregister))
+
+(cl-defmethod eglot-handle-request
+  (_server (_method (eql workspace/applyEdit)) &key _label edit)
+  "Handle server request workspace/applyEdit."
+  (eglot--apply-workspace-edit edit eglot-confirm-server-initiated-edits)
+  `(:applied t))
+
+(cl-defmethod eglot-handle-request
+  (server (_method (eql workspace/workspaceFolders)))
+  "Handle server request workspace/workspaceFolders."
+  (eglot-workspace-folders server))
+
+(defun eglot--TextDocumentIdentifier ()
+  "Compute TextDocumentIdentifier object for current buffer."
+  `(:uri ,(eglot--path-to-uri (or buffer-file-name
+                                  (ignore-errors
+                                    (buffer-file-name
+                                     (buffer-base-buffer)))))))
+
+(defvar-local eglot--versioned-identifier 0)
+
+(defun eglot--VersionedTextDocumentIdentifier ()
+  "Compute VersionedTextDocumentIdentifier object for current buffer."
+  (append (eglot--TextDocumentIdentifier)
+          `(:version ,eglot--versioned-identifier)))
+
+(defun eglot--TextDocumentItem ()
+  "Compute TextDocumentItem object for current buffer."
+  (append
+   (eglot--VersionedTextDocumentIdentifier)
+   (list :languageId
+         (eglot--language-id (eglot--current-server-or-lose))
+         :text
+         (eglot--widening
+          (buffer-substring-no-properties (point-min) (point-max))))))
+
+(defun eglot--TextDocumentPositionParams ()
+  "Compute TextDocumentPositionParams."
+  (list :textDocument (eglot--TextDocumentIdentifier)
+        :position (eglot--pos-to-lsp-position)))
+
+(defvar-local eglot--last-inserted-char nil
+  "If non-nil, value of the last inserted character in buffer.")
+
+(defun eglot--post-self-insert-hook ()
+  "Set `eglot--last-inserted-char', maybe call on-type-formatting."
+  (setq eglot--last-inserted-char last-input-event)
+  (let ((ot-provider (eglot--server-capable :documentOnTypeFormattingProvider)))
+    (when (and ot-provider
+               (ignore-errors ; github#906, some LS's send empty strings
+                 (or (eq last-input-event
+                         (seq-first (plist-get ot-provider :firstTriggerCharacter)))
+                     (cl-find last-input-event
+                              (plist-get ot-provider :moreTriggerCharacter)
+                              :key #'seq-first))))
+      (eglot-format (point) nil last-input-event))))
+
+(defvar eglot--workspace-symbols-cache (make-hash-table :test #'equal)
+  "Cache of `workspace/Symbol' results  used by `xref-find-definitions'.")
+
+(defun eglot--pre-command-hook ()
+  "Reset some temporary variables."
+  (clrhash eglot--workspace-symbols-cache)
+  (setq eglot--last-inserted-char nil))
+
+(defun eglot--CompletionParams ()
+  (append
+   (eglot--TextDocumentPositionParams)
+   `(:context
+     ,(if-let (trigger (and (characterp eglot--last-inserted-char)
+                            (cl-find eglot--last-inserted-char
+                                     (eglot--server-capable :completionProvider
+                                                            :triggerCharacters)
+                                     :key (lambda (str) (aref str 0))
+                                     :test #'char-equal)))
+          `(:triggerKind 2 :triggerCharacter ,trigger) `(:triggerKind 1)))))
+
+(defvar-local eglot--recent-changes nil
+  "Recent buffer changes as collected by `eglot--before-change'.")
+
+(cl-defmethod jsonrpc-connection-ready-p ((_server eglot-lsp-server) _what)
+  "Tell if SERVER is ready for WHAT in current buffer."
+  (and (cl-call-next-method) (not eglot--recent-changes)))
+
+(defvar-local eglot--change-idle-timer nil "Idle timer for didChange signals.")
+
+(defun eglot--before-change (beg end)
+  "Hook onto `before-change-functions' with BEG and END."
+  (when (listp eglot--recent-changes)
+    ;; Records BEG and END, crucially convert them into LSP
+    ;; (line/char) positions before that information is lost (because
+    ;; the after-change thingy doesn't know if newlines were
+    ;; deleted/added).  Also record markers of BEG and END
+    ;; (github#259)
+    (push `(,(eglot--pos-to-lsp-position beg)
+            ,(eglot--pos-to-lsp-position end)
+            (,beg . ,(copy-marker beg nil))
+            (,end . ,(copy-marker end t)))
+          eglot--recent-changes)))
+
+(defun eglot--after-change (beg end pre-change-length)
+  "Hook onto `after-change-functions'.
+Records BEG, END and PRE-CHANGE-LENGTH locally."
+  (cl-incf eglot--versioned-identifier)
+  (pcase (and (listp eglot--recent-changes)
+              (car eglot--recent-changes))
+    (`(,lsp-beg ,lsp-end
+                (,b-beg . ,b-beg-marker)
+                (,b-end . ,b-end-marker))
+     ;; github#259 and github#367: With `capitalize-word' or somesuch,
+     ;; `before-change-functions' always records the whole word's
+     ;; `b-beg' and `b-end'.  Similarly, when coalescing two lines
+     ;; into one, `fill-paragraph' they mark the end of the first line
+     ;; up to the end of the second line.  In both situations, args
+     ;; received here contradict that information: `beg' and `end'
+     ;; will differ by 1 and will likely only encompass the letter
+     ;; that was capitalized or, in the sentence-joining situation,
+     ;; the replacement of the newline with a space.  That's we keep
+     ;; markers _and_ positions so we're able to detect and correct
+     ;; this.  We ignore `beg', `len' and `pre-change-len' and send
+     ;; "fuller" information about the region from the markers.  I've
+     ;; also experimented with doing this unconditionally but it seems
+     ;; to break when newlines are added.
+     (if (and (= b-end b-end-marker) (= b-beg b-beg-marker)
+              (or (/= beg b-beg) (/= end b-end)))
+         (setcar eglot--recent-changes
+                 `(,lsp-beg ,lsp-end ,(- b-end-marker b-beg-marker)
+                            ,(buffer-substring-no-properties b-beg-marker
+                                                             b-end-marker)))
+       (setcar eglot--recent-changes
+               `(,lsp-beg ,lsp-end ,pre-change-length
+                          ,(buffer-substring-no-properties beg end)))))
+    (_ (setf eglot--recent-changes :emacs-messup)))
+  (when eglot--change-idle-timer (cancel-timer eglot--change-idle-timer))
+  (let ((buf (current-buffer)))
+    (setq eglot--change-idle-timer
+          (run-with-idle-timer
+           eglot-send-changes-idle-time
+           nil (lambda () (eglot--when-live-buffer buf
+                            (when eglot--managed-mode
+                              (eglot--signal-textDocument/didChange)
+                              (setq eglot--change-idle-timer nil))))))))
+
+;; HACK! Launching a deferred sync request with outstanding changes is a
+;; bad idea, since that might lead to the request never having a
+;; chance to run, because `jsonrpc-connection-ready-p'.
+(advice-add #'jsonrpc-request :before
+            (cl-function (lambda (_proc _method _params &key
+                                        deferred &allow-other-keys)
+                           (when (and eglot--managed-mode deferred)
+                             (eglot--signal-textDocument/didChange))))
+            '((name . eglot--signal-textDocument/didChange)))
+
+(defvar-local eglot-workspace-configuration ()
+  "Configure LSP servers specifically for a given project.
+
+This variable's value should be a plist (SECTION VALUE ...).
+SECTION is a keyword naming a parameter section relevant to a
+particular server.  VALUE is a plist or a primitive type
+converted to JSON also understood by that server.
+
+Instead of a plist, an alist ((SECTION . VALUE) ...) can be used
+instead, but this variant is less reliable and not recommended.
+
+This variable should be set as a directory-local variable.  See
+See info node `(emacs)Directory Variables' for various ways to to
+that.
+
+Here's an example value that establishes two sections relevant to
+the Pylsp and Gopls LSP servers:
+
+  (:pylsp (:plugins (:jedi_completion (:include_params t
+                                       :fuzzy t)
+                     :pylint (:enabled :json-false)))
+   :gopls (:usePlaceholders t))
+
+The value of this variable can also be a unary function of a
+single argument, which will be a connected `eglot-lsp-server'
+instance.  The function runs with `default-directory' set to the
+root of the current project.  It should return an object of the
+format described above.")
+
+;;;###autoload
+(put 'eglot-workspace-configuration 'safe-local-variable 'listp)
+
+(defun eglot-show-workspace-configuration (&optional server)
+  "Dump `eglot-workspace-configuration' as JSON for debugging."
+  (interactive (list (and (eglot-current-server)
+                          (eglot--read-server "Server configuration"
+                                              (eglot-current-server)))))
+  (let ((conf (eglot--workspace-configuration-plist server)))
+    (with-current-buffer (get-buffer-create "*EGLOT workspace configuration*")
+      (erase-buffer)
+      (insert (jsonrpc--json-encode conf))
+      (with-no-warnings
+        (require 'json)
+        (when (require 'json-mode nil t) (json-mode))
+        (json-pretty-print-buffer))
+      (pop-to-buffer (current-buffer)))))
+
+(defun eglot--workspace-configuration (server)
+  (if (functionp eglot-workspace-configuration)
+      (funcall eglot-workspace-configuration server)
+    eglot-workspace-configuration))
+
+(defun eglot--workspace-configuration-plist (server)
+  "Returns `eglot-workspace-configuration' suitable for serialization."
+  (let ((val (eglot--workspace-configuration server)))
+    (or (and (consp (car val))
+             (cl-loop for (section . v) in val
+                      collect (if (keywordp section) section
+                                (intern (format ":%s" section)))
+                      collect v))
+        val)))
+
+(defun eglot-signal-didChangeConfiguration (server)
+  "Send a `:workspace/didChangeConfiguration' signal to SERVER.
+When called interactively, use the currently active server"
+  (interactive (list (eglot--current-server-or-lose)))
+  (jsonrpc-notify
+   server :workspace/didChangeConfiguration
+   (list
+    :settings
+    (or (eglot--workspace-configuration-plist server)
+        eglot--{}))))
+
+(cl-defmethod eglot-handle-request
+  (server (_method (eql workspace/configuration)) &key items)
+  "Handle server request workspace/configuration."
+  (apply #'vector
+         (mapcar
+          (eglot--lambda ((ConfigurationItem) scopeUri section)
+            (with-temp-buffer
+              (let* ((uri-path (eglot--uri-to-path scopeUri))
+                     (default-directory
+                       (if (and (not (string-empty-p uri-path))
+                                (file-directory-p uri-path))
+                           (file-name-as-directory uri-path)
+                         (project-root (eglot--project server)))))
+                (setq-local major-mode (car (eglot--major-modes server)))
+                (hack-dir-local-variables-non-file-buffer)
+                (cl-loop for (wsection o)
+                         on (eglot--workspace-configuration-plist server)
+                         by #'cddr
+                         when (string=
+                               (if (keywordp wsection)
+                                   (substring (symbol-name wsection) 1)
+                                 wsection)
+                               section)
+                         return o))))
+          items)))
+
+(defun eglot--signal-textDocument/didChange ()
+  "Send textDocument/didChange to server."
+  (when eglot--recent-changes
+    (let* ((server (eglot--current-server-or-lose))
+           (sync-capability (eglot--server-capable :textDocumentSync))
+           (sync-kind (if (numberp sync-capability) sync-capability
+                        (plist-get sync-capability :change)))
+           (full-sync-p (or (eq sync-kind 1)
+                            (eq :emacs-messup eglot--recent-changes))))
+      (jsonrpc-notify
+       server :textDocument/didChange
+       (list
+        :textDocument (eglot--VersionedTextDocumentIdentifier)
+        :contentChanges
+        (if full-sync-p
+            (vector `(:text ,(eglot--widening
+                              (buffer-substring-no-properties (point-min)
+                                                              (point-max)))))
+          (cl-loop for (beg end len text) in (reverse eglot--recent-changes)
+                   ;; github#259: `capitalize-word' and commands based
+                   ;; on `casify_region' will cause multiple duplicate
+                   ;; empty entries in `eglot--before-change' calls
+                   ;; without an `eglot--after-change' reciprocal.
+                   ;; Weed them out here.
+                   when (numberp len)
+                   vconcat `[,(list :range `(:start ,beg :end ,end)
+                                    :rangeLength len :text text)]))))
+      (setq eglot--recent-changes nil)
+      (setf (eglot--spinner server) (list nil :textDocument/didChange t))
+      (jsonrpc--call-deferred server))))
+
+(defun eglot--signal-textDocument/didOpen ()
+  "Send textDocument/didOpen to server."
+  (setq eglot--recent-changes nil eglot--versioned-identifier 0)
+  (jsonrpc-notify
+   (eglot--current-server-or-lose)
+   :textDocument/didOpen `(:textDocument ,(eglot--TextDocumentItem))))
+
+(defun eglot--signal-textDocument/didClose ()
+  "Send textDocument/didClose to server."
+  (with-demoted-errors
+      "[eglot] error sending textDocument/didClose: %s"
+    (jsonrpc-notify
+     (eglot--current-server-or-lose)
+     :textDocument/didClose `(:textDocument ,(eglot--TextDocumentIdentifier)))))
+
+(defun eglot--signal-textDocument/willSave ()
+  "Send textDocument/willSave to server."
+  (let ((server (eglot--current-server-or-lose))
+        (params `(:reason 1 :textDocument ,(eglot--TextDocumentIdentifier))))
+    (when (eglot--server-capable :textDocumentSync :willSave)
+      (jsonrpc-notify server :textDocument/willSave params))
+    (when (eglot--server-capable :textDocumentSync :willSaveWaitUntil)
+      (ignore-errors
+        (eglot--apply-text-edits
+         (jsonrpc-request server :textDocument/willSaveWaitUntil params
+                          :timeout 0.5))))))
+
+(defun eglot--signal-textDocument/didSave ()
+  "Send textDocument/didSave to server."
+  (eglot--signal-textDocument/didChange)
+  (jsonrpc-notify
+   (eglot--current-server-or-lose)
+   :textDocument/didSave
+   (list
+    ;; TODO: Handle TextDocumentSaveRegistrationOptions to control this.
+    :text (buffer-substring-no-properties (point-min) (point-max))
+    :textDocument (eglot--TextDocumentIdentifier))))
+
+(defun eglot-flymake-backend (report-fn &rest _more)
+  "A Flymake backend for Eglot.
+Calls REPORT-FN (or arranges for it to be called) when the server
+publishes diagnostics.  Between calls to this function, REPORT-FN
+may be called multiple times (respecting the protocol of
+`flymake-backend-functions')."
+  (cond (eglot--managed-mode
+         (setq eglot--current-flymake-report-fn report-fn)
+         (eglot--report-to-flymake eglot--diagnostics))
+        (t
+         (funcall report-fn nil))))
+
+(defun eglot--report-to-flymake (diags)
+  "Internal helper for `eglot-flymake-backend'."
+  (save-restriction
+    (widen)
+    (funcall eglot--current-flymake-report-fn diags
+             ;; If the buffer hasn't changed since last
+             ;; call to the report function, flymake won't
+             ;; delete old diagnostics.  Using :region
+             ;; keyword forces flymake to delete
+             ;; them (github#159).
+             :region (cons (point-min) (point-max))))
+  (setq eglot--diagnostics diags))
+
+(defun eglot-xref-backend () "Eglot xref backend." 'eglot)
+
+(defvar eglot--temp-location-buffers (make-hash-table :test #'equal)
+  "Helper variable for `eglot--handling-xrefs'.")
+
+(defvar eglot-xref-lessp-function #'ignore
+  "Compare two `xref-item' objects for sorting.")
+
+(cl-defmacro eglot--collecting-xrefs ((collector) &rest body)
+  "Sort and handle xrefs collected with COLLECTOR in BODY."
+  (declare (indent 1) (debug (sexp &rest form)))
+  (let ((collected (cl-gensym "collected")))
+    `(unwind-protect
+         (let (,collected)
+           (cl-flet ((,collector (xref) (push xref ,collected)))
+             ,@body)
+           (setq ,collected (nreverse ,collected))
+           (sort ,collected eglot-xref-lessp-function))
+       (maphash (lambda (_uri buf) (kill-buffer buf)) eglot--temp-location-buffers)
+       (clrhash eglot--temp-location-buffers))))
+
+(defun eglot--xref-make-match (name uri range)
+  "Like `xref-make-match' but with LSP's NAME, URI and RANGE.
+Try to visit the target file for a richer summary line."
+  (pcase-let*
+      ((file (eglot--uri-to-path uri))
+       (visiting (or (find-buffer-visiting file)
+                     (gethash uri eglot--temp-location-buffers)))
+       (collect (lambda ()
+                  (eglot--widening
+                   (pcase-let* ((`(,beg . ,end) (eglot--range-region range))
+                                (bol (progn (goto-char beg) (line-beginning-position)))
+                                (substring (buffer-substring bol (line-end-position)))
+                                (hi-beg (- beg bol))
+                                (hi-end (- (min (line-end-position) end) bol)))
+                     (add-face-text-property hi-beg hi-end 'xref-match
+                                             t substring)
+                     (list substring (line-number-at-pos (point) t)
+                           (eglot-current-column) (- end beg))))))
+       (`(,summary ,line ,column ,length)
+        (cond
+         (visiting (with-current-buffer visiting (funcall collect)))
+         ((file-readable-p file) (with-current-buffer
+                                     (puthash uri (generate-new-buffer " *temp*")
+                                              eglot--temp-location-buffers)
+                                   (insert-file-contents file)
+                                   (funcall collect)))
+         (t ;; fall back to the "dumb strategy"
+          (let* ((start (cl-getf range :start))
+                 (line (1+ (cl-getf start :line)))
+                 (start-pos (cl-getf start :character))
+                 (end-pos (cl-getf (cl-getf range :end) :character)))
+            (list name line start-pos (- end-pos start-pos)))))))
+    (setf (gethash (expand-file-name file) eglot--servers-by-xrefed-file)
+          (eglot--current-server-or-lose))
+    (xref-make-match summary (xref-make-file-location file line column) length)))
+
+(defun eglot--workspace-symbols (pat &optional buffer)
+  "Ask for :workspace/symbol on PAT, return list of formatted strings.
+If BUFFER, switch to it before."
+  (with-current-buffer (or buffer (current-buffer))
+    (unless (eglot--server-capable :workspaceSymbolProvider)
+      (eglot--error "This LSP server isn't a :workspaceSymbolProvider"))
+    (mapcar
+     (lambda (wss)
+       (eglot--dbind ((WorkspaceSymbol) name containerName kind) wss
+         (propertize
+          (format "%s%s %s"
+                  (if (zerop (length containerName)) ""
+                    (concat (propertize containerName 'face 'shadow) " "))
+                  name
+                  (propertize (alist-get kind eglot--symbol-kind-names "Unknown")
+                              'face 'shadow))
+          'eglot--lsp-workspaceSymbol wss)))
+     (jsonrpc-request (eglot--current-server-or-lose) :workspace/symbol
+                      `(:query ,pat)))))
+
+(cl-defmethod xref-backend-identifier-completion-table ((_backend (eql eglot)))
+  "Yet another tricky connection between LSP and Elisp completion semantics."
+  (let ((buf (current-buffer)) (cache eglot--workspace-symbols-cache))
+    (cl-labels ((refresh (pat) (eglot--workspace-symbols pat buf))
+                (lookup-1 (pat) ;; check cache, else refresh
+                  (let ((probe (gethash pat cache :missing)))
+                    (if (eq probe :missing) (puthash pat (refresh pat) cache)
+                      probe)))
+                (lookup (pat)
+                  (let ((res (lookup-1 pat))
+                        (def (and (string= pat "") (gethash :default cache))))
+                    (append def res nil)))
+                (score (c)
+                  (cl-getf (get-text-property
+                            0 'eglot--lsp-workspaceSymbol c)
+                           :score 0)))
+      (lambda (string _pred action)
+        (pcase action
+          (`metadata `(metadata
+                       (cycle-sort-function
+                        . ,(lambda (completions)
+                             (cl-sort completions #'> :key #'score)))
+                       (category . eglot-indirection-joy)))
+          (`(eglot--lsp-tryc . ,point) `(eglot--lsp-tryc . (,string . ,point)))
+          (`(eglot--lsp-allc . ,_point) `(eglot--lsp-allc . ,(lookup string)))
+          (_ nil))))))
+
+(defun eglot--recover-workspace-symbol-meta (string)
+  "Search `eglot--workspace-symbols-cache' for rich entry of STRING."
+  (catch 'found
+    (maphash (lambda (_k v)
+               (while (consp v)
+                 ;; Like mess? Ask minibuffer.el about improper lists.
+                 (when (equal (car v) string) (throw 'found (car v)))
+                 (setq v (cdr v))))
+             eglot--workspace-symbols-cache)))
+
+(add-to-list 'completion-category-overrides
+             '(eglot-indirection-joy (styles . (eglot--lsp-backend-style))))
+
+(cl-defmethod xref-backend-identifier-at-point ((_backend (eql eglot)))
+  (let ((attempt
+         (and (xref--prompt-p this-command)
+              (puthash :default
+                       (ignore-errors
+                         (eglot--workspace-symbols (symbol-name (symbol-at-point))))
+                       eglot--workspace-symbols-cache))))
+    (if attempt (car attempt) "LSP identifier at point")))
+
+(defvar eglot--lsp-xref-refs nil
+  "`xref' objects for overriding `xref-backend-references''s.")
+
+(cl-defun eglot--lsp-xrefs-for-method (method &key extra-params capability)
+  "Make `xref''s for METHOD, EXTRA-PARAMS, check CAPABILITY."
+  (unless (eglot--server-capable
+           (or capability
+               (intern
+                (format ":%sProvider"
+                        (cadr (split-string (symbol-name method)
+                                            "/"))))))
+    (eglot--error "Sorry, this server doesn't do %s" method))
+  (let ((response
+         (jsonrpc-request
+          (eglot--current-server-or-lose)
+          method (append (eglot--TextDocumentPositionParams) extra-params))))
+    (eglot--collecting-xrefs (collect)
+      (mapc
+       (lambda (loc-or-loc-link)
+         (let ((sym-name (symbol-name (symbol-at-point))))
+           (eglot--dcase loc-or-loc-link
+             (((LocationLink) targetUri targetSelectionRange)
+              (collect (eglot--xref-make-match sym-name
+                                               targetUri targetSelectionRange)))
+             (((Location) uri range)
+              (collect (eglot--xref-make-match sym-name
+                                               uri range))))))
+       (if (vectorp response) response (and response (list response)))))))
+
+(cl-defun eglot--lsp-xref-helper (method &key extra-params capability )
+  "Helper for `eglot-find-declaration' & friends."
+  (let ((eglot--lsp-xref-refs (eglot--lsp-xrefs-for-method
+                               method
+                               :extra-params extra-params
+                               :capability capability)))
+    (if eglot--lsp-xref-refs
+        (xref-find-references "LSP identifier at point.")
+      (eglot--message "%s returned no references" method))))
+
+(defun eglot-find-declaration ()
+  "Find declaration for SYM, the identifier at point."
+  (interactive)
+  (eglot--lsp-xref-helper :textDocument/declaration))
+
+(defun eglot-find-implementation ()
+  "Find implementation for SYM, the identifier at point."
+  (interactive)
+  (eglot--lsp-xref-helper :textDocument/implementation))
+
+(defun eglot-find-typeDefinition ()
+  "Find type definition for SYM, the identifier at point."
+  (interactive)
+  (eglot--lsp-xref-helper :textDocument/typeDefinition))
+
+(cl-defmethod xref-backend-definitions ((_backend (eql eglot)) id)
+  (let ((probe (eglot--recover-workspace-symbol-meta id)))
+    (if probe
+        (eglot--dbind ((WorkspaceSymbol) name location)
+            (get-text-property 0 'eglot--lsp-workspaceSymbol probe)
+          (eglot--dbind ((Location) uri range) location
+            (list (eglot--xref-make-match name uri range))))
+        (eglot--lsp-xrefs-for-method :textDocument/definition))))
+
+(cl-defmethod xref-backend-references ((_backend (eql eglot)) _identifier)
+  (or
+   eglot--lsp-xref-refs
+   (eglot--lsp-xrefs-for-method
+    :textDocument/references :extra-params `(:context (:includeDeclaration t)))))
+
+(cl-defmethod xref-backend-apropos ((_backend (eql eglot)) pattern)
+  (when (eglot--server-capable :workspaceSymbolProvider)
+    (eglot--collecting-xrefs (collect)
+      (mapc
+       (eglot--lambda ((SymbolInformation) name location)
+         (eglot--dbind ((Location) uri range) location
+           (collect (eglot--xref-make-match name uri range))))
+       (jsonrpc-request (eglot--current-server-or-lose)
+                        :workspace/symbol
+                        `(:query ,pattern))))))
+
+(defun eglot-format-buffer ()
+  "Format contents of current buffer."
+  (interactive)
+  (eglot-format nil nil))
+
+(defun eglot-format (&optional beg end on-type-format)
+  "Format region BEG END.
+If either BEG or END is nil, format entire buffer.
+Interactively, format active region, or entire buffer if region
+is not active.
+
+If non-nil, ON-TYPE-FORMAT is a character just inserted at BEG
+for which LSP on-type-formatting should be requested."
+  (interactive (and (region-active-p) (list (region-beginning) (region-end))))
+  (pcase-let ((`(,method ,cap ,args)
+               (cond
+                ((and beg on-type-format)
+                 `(:textDocument/onTypeFormatting
+                   :documentOnTypeFormattingProvider
+                   ,`(:position ,(eglot--pos-to-lsp-position beg)
+                      :ch ,(string on-type-format))))
+                ((and beg end)
+                 `(:textDocument/rangeFormatting
+                   :documentRangeFormattingProvider
+                   (:range ,(list :start (eglot--pos-to-lsp-position beg)
+                                  :end (eglot--pos-to-lsp-position end)))))
+                (t
+                 '(:textDocument/formatting :documentFormattingProvider nil)))))
+    (unless (eglot--server-capable cap)
+      (eglot--error "Server can't format!"))
+    (eglot--apply-text-edits
+     (jsonrpc-request
+      (eglot--current-server-or-lose)
+      method
+      (cl-list*
+       :textDocument (eglot--TextDocumentIdentifier)
+       :options (list :tabSize tab-width
+                      :insertSpaces (if indent-tabs-mode :json-false t)
+                      :insertFinalNewline (if require-final-newline t :json-false)
+                      :trimFinalNewlines (if delete-trailing-lines t :json-false))
+       args)
+      :deferred method))))
+
+(defun eglot-completion-at-point ()
+  "Eglot's `completion-at-point' function."
+  ;; Commit logs for this function help understand what's going on.
+  (when-let (completion-capability (eglot--server-capable :completionProvider))
+    (let* ((server (eglot--current-server-or-lose))
+           (sort-completions
+            (lambda (completions)
+              (cl-sort completions
+                       #'string-lessp
+                       :key (lambda (c)
+                              (or (plist-get
+                                   (get-text-property 0 'eglot--lsp-item c)
+                                   :sortText)
+                                  "")))))
+           (metadata `(metadata (category . eglot)
+                                (display-sort-function . ,sort-completions)))
+           resp items (cached-proxies :none)
+           (proxies
+            (lambda ()
+              (if (listp cached-proxies) cached-proxies
+                (setq resp
+                      (jsonrpc-request server
+                                       :textDocument/completion
+                                       (eglot--CompletionParams)
+                                       :deferred :textDocument/completion
+                                       :cancel-on-input t))
+                (setq items (append
+                             (if (vectorp resp) resp (plist-get resp :items))
+                             nil))
+                (setq cached-proxies
+                      (mapcar
+                       (jsonrpc-lambda
+                           (&rest item &key label insertText insertTextFormat
+                                  &allow-other-keys)
+                         (let ((proxy
+                                (cond ((and (eql insertTextFormat 2)
+                                            (eglot--snippet-expansion-fn))
+                                       (string-trim-left label))
+                                      ((and insertText
+                                            (not (string-empty-p insertText)))
+                                       insertText)
+                                      (t
+                                       (string-trim-left label)))))
+                           (unless (zerop (length proxy))
+                             (put-text-property 0 1 'eglot--lsp-item item proxy))
+                           proxy))
+                       items)))))
+           (resolved (make-hash-table))
+           (resolve-maybe
+            ;; Maybe completion/resolve JSON object `lsp-comp' into
+            ;; another JSON object, if at all possible.  Otherwise,
+            ;; just return lsp-comp.
+            (lambda (lsp-comp)
+              (or (gethash lsp-comp resolved)
+                  (setf (gethash lsp-comp resolved)
+                        (if (and (eglot--server-capable :completionProvider
+                                                        :resolveProvider)
+                                 (plist-get lsp-comp :data))
+                            (jsonrpc-request server :completionItem/resolve
+                                             lsp-comp :cancel-on-input t)
+                          lsp-comp)))))
+           (bounds (bounds-of-thing-at-point 'symbol)))
+      (list
+       (or (car bounds) (point))
+       (or (cdr bounds) (point))
+       (lambda (probe pred action)
+         (cond
+          ((eq action 'metadata) metadata)               ; metadata
+          ((eq action 'lambda)                           ; test-completion
+           (test-completion probe (funcall proxies)))
+          ((eq (car-safe action) 'boundaries) nil)       ; boundaries
+          ((null action)                                 ; try-completion
+           (try-completion probe (funcall proxies)))
+          ((eq action t)                                 ; all-completions
+           (all-completions
+            ""
+            (funcall proxies)
+            (lambda (proxy)
+              (let* ((item (get-text-property 0 'eglot--lsp-item proxy))
+                     (filterText (plist-get item :filterText)))
+                (and (or (null pred) (funcall pred proxy))
+                     (string-prefix-p
+                      probe (or filterText proxy) completion-ignore-case))))))))
+       :annotation-function
+       (lambda (proxy)
+         (eglot--dbind ((CompletionItem) detail kind)
+             (get-text-property 0 'eglot--lsp-item proxy)
+           (let* ((detail (and (stringp detail)
+                               (not (string= detail ""))
+                               detail))
+                  (annotation
+                   (or detail
+                       (cdr (assoc kind eglot--kind-names)))))
+             (when annotation
+               (concat " "
+                       (propertize annotation
+                                   'face 'font-lock-function-name-face))))))
+       :company-kind
+       ;; Associate each lsp-item with a lsp-kind symbol.
+       (lambda (proxy)
+         (when-let* ((lsp-item (get-text-property 0 'eglot--lsp-item proxy))
+                     (kind (alist-get (plist-get lsp-item :kind)
+                                      eglot--kind-names)))
+           (intern (downcase kind))))
+       :company-deprecated
+       (lambda (proxy)
+         (when-let ((lsp-item (get-text-property 0 'eglot--lsp-item proxy)))
+           (or (seq-contains-p (plist-get lsp-item :tags)
+                               1)
+               (eq t (plist-get lsp-item :deprecated)))))
+       :company-docsig
+       ;; FIXME: autoImportText is specific to the pyright language server
+       (lambda (proxy)
+         (when-let* ((lsp-comp (get-text-property 0 'eglot--lsp-item proxy))
+                     (data (plist-get (funcall resolve-maybe lsp-comp) :data))
+                     (import-text (plist-get data :autoImportText)))
+           import-text))
+       :company-doc-buffer
+       (lambda (proxy)
+         (let* ((documentation
+                 (let ((lsp-comp (get-text-property 0 'eglot--lsp-item proxy)))
+                   (plist-get (funcall resolve-maybe lsp-comp) :documentation)))
+                (formatted (and documentation
+                                (eglot--format-markup documentation))))
+           (when formatted
+             (with-current-buffer (get-buffer-create " *eglot doc*")
+               (erase-buffer)
+               (insert formatted)
+               (current-buffer)))))
+       :company-require-match 'never
+       :company-prefix-length
+       (save-excursion
+         (when (car bounds) (goto-char (car bounds)))
+         (when (listp completion-capability)
+           (looking-back
+            (regexp-opt
+             (cl-coerce (cl-getf completion-capability :triggerCharacters) 'list))
+            (line-beginning-position))))
+       :exit-function
+       (lambda (proxy status)
+         (when (memq status '(finished exact))
+           ;; To assist in using this whole `completion-at-point'
+           ;; function inside `completion-in-region', ensure the exit
+           ;; function runs in the buffer where the completion was
+           ;; triggered from.  This should probably be in Emacs itself.
+           ;; (github#505)
+           (with-current-buffer (if (minibufferp)
+                                    (window-buffer (minibuffer-selected-window))
+                                  (current-buffer))
+             (eglot--dbind ((CompletionItem) insertTextFormat
+                            insertText textEdit additionalTextEdits label)
+                 (funcall
+                  resolve-maybe
+                  (or (get-text-property 0 'eglot--lsp-item proxy)
+                      ;; When selecting from the *Completions*
+                      ;; buffer, `proxy' won't have any properties.
+                      ;; A lookup should fix that (github#148)
+                      (get-text-property
+                       0 'eglot--lsp-item
+                       (cl-find proxy (funcall proxies) :test #'string=))))
+               (let ((snippet-fn (and (eql insertTextFormat 2)
+                                      (eglot--snippet-expansion-fn))))
+                 (cond (textEdit
+                        ;; Undo (yes, undo) the newly inserted completion.
+                        ;; If before completion the buffer was "foo.b" and
+                        ;; now is "foo.bar", `proxy' will be "bar".  We
+                        ;; want to delete only "ar" (`proxy' minus the
+                        ;; symbol whose bounds we've calculated before)
+                        ;; (github#160).
+                        (delete-region (+ (- (point) (length proxy))
+                                          (if bounds
+                                              (- (cdr bounds) (car bounds))
+                                            0))
+                                       (point))
+                        (eglot--dbind ((TextEdit) range newText) textEdit
+                          (pcase-let ((`(,beg . ,end)
+                                       (eglot--range-region range)))
+                            (delete-region beg end)
+                            (goto-char beg)
+                            (funcall (or snippet-fn #'insert) newText))))
+                       (snippet-fn
+                        ;; A snippet should be inserted, but using plain
+                        ;; `insertText'.  This requires us to delete the
+                        ;; whole completion, since `insertText' is the full
+                        ;; completion's text.
+                        (delete-region (- (point) (length proxy)) (point))
+                        (funcall snippet-fn (or insertText label))))
+                 (when (cl-plusp (length additionalTextEdits))
+                   (eglot--apply-text-edits additionalTextEdits)))
+               (eglot--signal-textDocument/didChange)
+               (eldoc)))))))))
+
+(defun eglot--hover-info (contents &optional _range)
+  (mapconcat #'eglot--format-markup
+             (if (vectorp contents) contents (list contents)) "\n"))
+ 
+(defun eglot--sig-info (sigs active-sig sig-help-active-param)
+  (cl-loop
+   for (sig . moresigs) on (append sigs nil) for i from 0
+   concat
+   (eglot--dbind ((SignatureInformation) label documentation parameters activeParameter) sig
+     (with-temp-buffer
+       (save-excursion (insert label))
+       (let ((active-param (or activeParameter sig-help-active-param))
+             params-start params-end)
+         ;; Ad-hoc attempt to parse label as <name>(<params>)
+         (when (looking-at "\\([^(]+\\)(\\([^)]+\\))")
+           (setq params-start (match-beginning 2) params-end (match-end 2))
+           (add-face-text-property (match-beginning 1) (match-end 1)
+                                   'font-lock-function-name-face))
+         (when (eql i active-sig)
+           ;; Decide whether to add one-line-summary to signature line
+           (when (and (stringp documentation)
+                      (string-match "[[:space:]]*\\([^.\r\n]+[.]?\\)"
+                                    documentation))
+             (setq documentation (match-string 1 documentation))
+             (unless (string-prefix-p (string-trim documentation) label)
+               (goto-char (point-max))
+               (insert ": " (eglot--format-markup documentation))))
+           ;; Decide what to do with the active parameter...
+           (when (and (eql i active-sig) active-param
+                      (< -1 active-param (length parameters)))
+             (eglot--dbind ((ParameterInformation) label documentation)
+                 (aref parameters active-param)
+               ;; ...perhaps highlight it in the formals list
+               (when params-start
+                 (goto-char params-start)
+                 (pcase-let
+                     ((`(,beg ,end)
+                       (if (stringp label)
+                           (let ((case-fold-search nil))
+                             (and (re-search-forward
+                                   (concat "\\<" (regexp-quote label) "\\>")
+                                   params-end t)
+                                  (list (match-beginning 0) (match-end 0))))
+                         (mapcar #'1+ (append label nil)))))
+                   (if (and beg end)
+                       (add-face-text-property
+                        beg end
+                        'eldoc-highlight-function-argument))))
+               ;; ...and/or maybe add its doc on a line by its own.
+               (when documentation
+                 (goto-char (point-max))
+                 (insert "\n"
+                         (propertize
+                          (if (stringp label)
+                              label
+                            (apply #'buffer-substring (mapcar #'1+ label)))
+                          'face 'eldoc-highlight-function-argument)
+                         ": " (eglot--format-markup documentation))))))
+         (buffer-string))))
+   when moresigs concat "\n"))
+
+(defun eglot-signature-eldoc-function (cb)
+  "A member of `eldoc-documentation-functions', for signatures."
+  (when (eglot--server-capable :signatureHelpProvider)
+    (let ((buf (current-buffer)))
+      (jsonrpc-async-request
+       (eglot--current-server-or-lose)
+       :textDocument/signatureHelp (eglot--TextDocumentPositionParams)
+       :success-fn
+       (eglot--lambda ((SignatureHelp)
+                       signatures activeSignature activeParameter)
+         (eglot--when-buffer-window buf
+           (funcall cb
+                    (unless (seq-empty-p signatures)
+                      (eglot--sig-info signatures
+                                       activeSignature
+                                       activeParameter)))))
+       :deferred :textDocument/signatureHelp))
+    t))
+
+(defun eglot-hover-eldoc-function (cb)
+  "A member of `eldoc-documentation-functions', for hover."
+  (when (eglot--server-capable :hoverProvider)
+    (let ((buf (current-buffer)))
+      (jsonrpc-async-request
+       (eglot--current-server-or-lose)
+       :textDocument/hover (eglot--TextDocumentPositionParams)
+       :success-fn (eglot--lambda ((Hover) contents range)
+                     (eglot--when-buffer-window buf
+                       (let ((info (unless (seq-empty-p contents)
+                                     (eglot--hover-info contents range))))
+                         (funcall cb info :buffer t))))
+       :deferred :textDocument/hover))
+    (eglot--highlight-piggyback cb)
+    t))
+
+(defvar eglot--highlights nil "Overlays for textDocument/documentHighlight.")
+
+(defun eglot--highlight-piggyback (_cb)
+  "Request and handle `:textDocument/documentHighlight'."
+  ;; FIXME: Obviously, this is just piggy backing on eldoc's calls for
+  ;; convenience, as shown by the fact that we just ignore cb.
+  (let ((buf (current-buffer)))
+    (when (eglot--server-capable :documentHighlightProvider)
+      (jsonrpc-async-request
+       (eglot--current-server-or-lose)
+       :textDocument/documentHighlight (eglot--TextDocumentPositionParams)
+       :success-fn
+       (lambda (highlights)
+         (mapc #'delete-overlay eglot--highlights)
+         (setq eglot--highlights
+               (eglot--when-buffer-window buf
+                 (mapcar
+                  (eglot--lambda ((DocumentHighlight) range)
+                    (pcase-let ((`(,beg . ,end)
+                                 (eglot--range-region range)))
+                      (let ((ov (make-overlay beg end)))
+                        (overlay-put ov 'face 'eglot-highlight-symbol-face)
+                        (overlay-put ov 'modification-hooks
+                                     `(,(lambda (o &rest _) (delete-overlay o))))
+                        ov)))
+                  highlights))))
+       :deferred :textDocument/documentHighlight)
+      nil)))
+
+(defun eglot-imenu ()
+  "Eglot's `imenu-create-index-function'.
+Returns a list as described in docstring of `imenu--index-alist'."
+  (cl-labels
+      ((unfurl (obj)
+         (eglot--dcase obj
+           (((SymbolInformation)) (list obj))
+           (((DocumentSymbol) name children)
+            (cons obj
+                  (mapcar
+                   (lambda (c)
+                     (plist-put
+                      c :containerName
+                      (let ((existing (plist-get c :containerName)))
+                        (if existing (format "%s::%s" name existing)
+                          name))))
+                   (mapcan #'unfurl children)))))))
+    (mapcar
+     (pcase-lambda (`(,kind . ,objs))
+       (cons
+        (alist-get kind eglot--symbol-kind-names "Unknown")
+        (mapcan (pcase-lambda (`(,container . ,objs))
+                  (let ((elems (mapcar
+                                (lambda (obj)
+                                  (cons (plist-get obj :name)
+                                        (car (eglot--range-region
+                                              (eglot--dcase obj
+                                                (((SymbolInformation) location)
+                                                 (plist-get location :range))
+                                                (((DocumentSymbol) selectionRange)
+                                                 selectionRange))))))
+                                objs)))
+                    (if container (list (cons container elems)) elems)))
+                (seq-group-by
+                 (lambda (e) (plist-get e :containerName)) objs))))
+     (seq-group-by
+      (lambda (obj) (plist-get obj :kind))
+      (mapcan #'unfurl
+              (jsonrpc-request (eglot--current-server-or-lose)
+                               :textDocument/documentSymbol
+                               `(:textDocument
+                                 ,(eglot--TextDocumentIdentifier))
+                               :cancel-on-input non-essential))))))
+
+(defun eglot--apply-text-edits (edits &optional version)
+  "Apply EDITS for current buffer if at VERSION, or if it's nil."
+  (unless (or (not version) (equal version eglot--versioned-identifier))
+    (jsonrpc-error "Edits on `%s' require version %d, you have %d"
+                   (current-buffer) version eglot--versioned-identifier))
+  (atomic-change-group
+    (let* ((change-group (prepare-change-group))
+           (howmany (length edits))
+           (reporter (make-progress-reporter
+                      (format "[eglot] applying %s edits to `%s'..."
+                              howmany (current-buffer))
+                      0 howmany))
+           (done 0))
+      (mapc (pcase-lambda (`(,newText ,beg . ,end))
+              (let ((source (current-buffer)))
+                (with-temp-buffer
+                  (insert newText)
+                  (let ((temp (current-buffer)))
+                    (with-current-buffer source
+                      (save-excursion
+                        (save-restriction
+                          (narrow-to-region beg end)
+
+                          ;; On emacs versions < 26.2,
+                          ;; `replace-buffer-contents' is buggy - it calls
+                          ;; change functions with invalid arguments - so we
+                          ;; manually call the change functions here.
+                          ;;
+                          ;; See emacs bugs #32237, #32278:
+                          ;; https://debbugs.gnu.org/cgi/bugreport.cgi?bug=32237
+                          ;; https://debbugs.gnu.org/cgi/bugreport.cgi?bug=32278
+                          (let ((inhibit-modification-hooks t)
+                                (length (- end beg))
+                                (beg (marker-position beg))
+                                (end (marker-position end)))
+                            (run-hook-with-args 'before-change-functions
+                                                beg end)
+                            (replace-buffer-contents temp)
+                            (run-hook-with-args 'after-change-functions
+                                                beg (+ beg (length newText))
+                                                length))))
+                      (progress-reporter-update reporter (cl-incf done)))))))
+            (mapcar (eglot--lambda ((TextEdit) range newText)
+                      (cons newText (eglot--range-region range 'markers)))
+                    (reverse edits)))
+      (undo-amalgamate-change-group change-group)
+      (progress-reporter-done reporter))))
+
+(defun eglot--apply-workspace-edit (wedit &optional confirm)
+  "Apply the workspace edit WEDIT.  If CONFIRM, ask user first."
+  (eglot--dbind ((WorkspaceEdit) changes documentChanges) wedit
+    (let ((prepared
+           (mapcar (eglot--lambda ((TextDocumentEdit) textDocument edits)
+                     (eglot--dbind ((VersionedTextDocumentIdentifier) uri version)
+                         textDocument
+                       (list (eglot--uri-to-path uri) edits version)))
+                   documentChanges)))
+      (unless (and changes documentChanges)
+        ;; We don't want double edits, and some servers send both
+        ;; changes and documentChanges.  This unless ensures that we
+        ;; prefer documentChanges over changes.
+        (cl-loop for (uri edits) on changes by #'cddr
+                 do (push (list (eglot--uri-to-path uri) edits) prepared)))
+      (if (or confirm
+              (cl-notevery #'find-buffer-visiting
+                           (mapcar #'car prepared)))
+          (unless (y-or-n-p
+                   (format "[eglot] Server wants to edit:\n  %s\n Proceed? "
+                           (mapconcat #'identity (mapcar #'car prepared) "\n  ")))
+            (jsonrpc-error "User cancelled server edit")))
+      (cl-loop for edit in prepared
+               for (path edits version) = edit
+               do (with-current-buffer (find-file-noselect path)
+                    (eglot--apply-text-edits edits version))
+               finally (eldoc) (eglot--message "Edit successful!")))))
+
+(defun eglot-rename (newname)
+  "Rename the current symbol to NEWNAME."
+  (interactive
+   (list (read-from-minibuffer
+          (format "Rename `%s' to: " (or (thing-at-point 'symbol t)
+                                         "unknown symbol"))
+          nil nil nil nil
+          (symbol-name (symbol-at-point)))))
+  (unless (eglot--server-capable :renameProvider)
+    (eglot--error "Server can't rename!"))
+  (eglot--apply-workspace-edit
+   (jsonrpc-request (eglot--current-server-or-lose)
+                    :textDocument/rename `(,@(eglot--TextDocumentPositionParams)
+                                           :newName ,newname))
+   current-prefix-arg))
+
+(defun eglot--region-bounds ()
+  "Region bounds if active, else bounds of things at point."
+  (if (use-region-p) `(,(region-beginning) ,(region-end))
+    (let ((boftap (bounds-of-thing-at-point 'sexp)))
+      (list (car boftap) (cdr boftap)))))
+
+(defun eglot-code-actions (beg &optional end action-kind interactive)
+  "Find LSP code actions of type ACTION-KIND between BEG and END.
+Interactively, offer to execute them.
+If ACTION-KIND is nil, consider all kinds of actions.
+Interactively, default BEG and END to region's bounds else BEG is
+point and END is nil, which results in a request for code actions
+at point.  With prefix argument, prompt for ACTION-KIND."
+  (interactive
+   `(,@(eglot--region-bounds)
+     ,(and current-prefix-arg
+           (completing-read "[eglot] Action kind: "
+                            '("quickfix" "refactor.extract" "refactor.inline"
+                              "refactor.rewrite" "source.organizeImports")))
+     t))
+  (unless (or (not interactive)
+              (eglot--server-capable :codeActionProvider))
+    (eglot--error "Server can't execute code actions!"))
+  (let* ((server (eglot--current-server-or-lose))
+         (actions
+          (jsonrpc-request
+           server
+           :textDocument/codeAction
+           (list :textDocument (eglot--TextDocumentIdentifier)
+                 :range (list :start (eglot--pos-to-lsp-position beg)
+                              :end (eglot--pos-to-lsp-position end))
+                 :context
+                 `(:diagnostics
+                   [,@(cl-loop for diag in (flymake-diagnostics beg end)
+                               when (cdr (assoc 'eglot-lsp-diag
+                                                (eglot--diag-data diag)))
+                               collect it)]
+                   ,@(when action-kind `(:only [,action-kind]))))
+           :deferred t))
+         ;; Redo filtering, in case the `:only' didn't go through.
+         (actions (cl-loop for a across actions
+                           when (or (not action-kind)
+                                    (equal action-kind (plist-get a :kind)))
+                           collect a)))
+    (if interactive
+        (eglot--read-execute-code-action actions server action-kind)
+      actions)))
+
+(defun eglot--read-execute-code-action (actions server &optional action-kind)
+  "Helper for interactive calls to `eglot-code-actions'"
+  (let* ((menu-items
+          (or (cl-loop for a in actions
+                       collect (cons (plist-get a :title) a))
+              (apply #'eglot--error
+                     (if action-kind `("No \"%s\" code actions here" ,action-kind)
+                       `("No code actions here")))))
+         (preferred-action (cl-find-if
+                            (lambda (menu-item)
+                              (plist-get (cdr menu-item) :isPreferred))
+                            menu-items))
+         (default-action (car (or preferred-action (car menu-items))))
+         (chosen (if (and action-kind (null (cadr menu-items)))
+                     (cdr (car menu-items))
+                   (if (listp last-nonmenu-event)
+                       (x-popup-menu last-nonmenu-event `("Eglot code actions:"
+                                                          ("dummy" ,@menu-items)))
+                     (cdr (assoc (completing-read
+                                  (format "[eglot] Pick an action (default %s): "
+                                          default-action)
+                                  menu-items nil t nil nil default-action)
+                                 menu-items))))))
+    (eglot--dcase chosen
+      (((Command) command arguments)
+       (eglot-execute-command server (intern command) arguments))
+      (((CodeAction) edit command)
+       (when edit (eglot--apply-workspace-edit edit))
+       (when command
+         (eglot--dbind ((Command) command arguments) command
+           (eglot-execute-command server (intern command) arguments)))))))
+
+(defmacro eglot--code-action (name kind)
+  "Define NAME to execute KIND code action."
+  `(defun ,name (beg &optional end)
+     ,(format "Execute `%s' code actions between BEG and END." kind)
+     (interactive (eglot--region-bounds))
+     (eglot-code-actions beg end ,kind)))
+
+(eglot--code-action eglot-code-action-organize-imports "source.organizeImports")
+(eglot--code-action eglot-code-action-extract "refactor.extract")
+(eglot--code-action eglot-code-action-inline "refactor.inline")
+(eglot--code-action eglot-code-action-rewrite "refactor.rewrite")
+(eglot--code-action eglot-code-action-quickfix "quickfix")
+
+
+;;; Dynamic registration
+;;;
+(cl-defmethod eglot-register-capability
+  (server (method (eql workspace/didChangeWatchedFiles)) id &key watchers)
+  "Handle dynamic registration of workspace/didChangeWatchedFiles."
+  (eglot-unregister-capability server method id)
+  (let* (success
+         (globs (mapcar
+                 (eglot--lambda ((FileSystemWatcher) globPattern)
+                   (eglot--glob-compile globPattern t t))
+                 watchers))
+         (dirs-to-watch
+          (delete-dups (mapcar #'file-name-directory
+                               (project-files
+                                (eglot--project server))))))
+    (cl-labels
+        ((handle-event
+          (event)
+          (pcase-let ((`(,desc ,action ,file ,file1) event))
+            (cond
+             ((and (memq action '(created changed deleted))
+                   (cl-find file globs :test (lambda (f g) (funcall g f))))
+              (jsonrpc-notify
+               server :workspace/didChangeWatchedFiles
+               `(:changes ,(vector `(:uri ,(eglot--path-to-uri file)
+                                          :type ,(cl-case action
+                                                   (created 1)
+                                                   (changed 2)
+                                                   (deleted 3)))))))
+             ((eq action 'renamed)
+              (handle-event `(,desc 'deleted ,file))
+              (handle-event `(,desc 'created ,file1)))))))
+      (unwind-protect
+          (progn
+            (dolist (dir dirs-to-watch)
+              (push (file-notify-add-watch dir '(change) #'handle-event)
+                    (gethash id (eglot--file-watches server))))
+            (setq
+             success
+             `(:message ,(format "OK, watching %s directories in %s watchers"
+                                 (length dirs-to-watch) (length watchers)))))
+        (unless success
+          (eglot-unregister-capability server method id))))))
+
+(cl-defmethod eglot-unregister-capability
+  (server (_method (eql workspace/didChangeWatchedFiles)) id)
+  "Handle dynamic unregistration of workspace/didChangeWatchedFiles."
+  (mapc #'file-notify-rm-watch (gethash id (eglot--file-watches server)))
+  (remhash id (eglot--file-watches server))
+  (list t "OK"))
+
+
+;;; Glob heroics
+;;;
+(defun eglot--glob-parse (glob)
+  "Compute list of (STATE-SYM EMITTER-FN PATTERN)."
+  (with-temp-buffer
+    (save-excursion (insert glob))
+    (cl-loop
+     with grammar = '((:**      "\\*\\*/?"              eglot--glob-emit-**)
+                      (:*       "\\*"                   eglot--glob-emit-*)
+                      (:?       "\\?"                   eglot--glob-emit-?)
+                      (:{}      "{[^][*{}]+}"           eglot--glob-emit-{})
+                      (:range   "\\[\\^?[^][/,*{}]+\\]" eglot--glob-emit-range)
+                      (:literal "[^][,*?{}]+"           eglot--glob-emit-self))
+     until (eobp)
+     collect (cl-loop
+              for (_token regexp emitter) in grammar
+              thereis (and (re-search-forward (concat "\\=" regexp) nil t)
+                           (list (cl-gensym "state-") emitter (match-string 0)))
+              finally (error "Glob '%s' invalid at %s" (buffer-string) (point))))))
+
+(defun eglot--glob-compile (glob &optional byte-compile noerror)
+  "Convert GLOB into Elisp function.  Maybe BYTE-COMPILE it.
+If NOERROR, return predicate, else erroring function."
+  (let* ((states (eglot--glob-parse glob))
+         (body `(with-current-buffer (get-buffer-create " *eglot-glob-matcher*")
+                  (erase-buffer)
+                  (save-excursion (insert string))
+                  (cl-labels ,(cl-loop for (this that) on states
+                                       for (self emit text) = this
+                                       for next = (or (car that) 'eobp)
+                                       collect (funcall emit text self next))
+                    (or (,(caar states))
+                        (error "Glob done but more unmatched text: '%s'"
+                               (buffer-substring (point) (point-max)))))))
+         (form `(lambda (string) ,(if noerror `(ignore-errors ,body) body))))
+    (if byte-compile (byte-compile form) form)))
+
+(defun eglot--glob-emit-self (text self next)
+  `(,self () (re-search-forward ,(concat "\\=" (regexp-quote text))) (,next)))
+
+(defun eglot--glob-emit-** (_ self next)
+  `(,self () (or (ignore-errors (save-excursion (,next)))
+                 (and (re-search-forward "\\=/?[^/]+/?") (,self)))))
+
+(defun eglot--glob-emit-* (_ self next)
+  `(,self () (re-search-forward "\\=[^/]")
+          (or (ignore-errors (save-excursion (,next))) (,self))))
+
+(defun eglot--glob-emit-? (_ self next)
+  `(,self () (re-search-forward "\\=[^/]") (,next)))
+
+(defun eglot--glob-emit-{} (arg self next)
+  (let ((alternatives (split-string (substring arg 1 (1- (length arg))) ",")))
+    `(,self ()
+            (or (re-search-forward ,(concat "\\=" (regexp-opt alternatives)) nil t)
+                (error "Failed matching any of %s" ',alternatives))
+            (,next))))
+
+(defun eglot--glob-emit-range (arg self next)
+  (when (eq ?! (aref arg 1)) (aset arg 1 ?^))
+  `(,self () (re-search-forward ,(concat "\\=" arg)) (,next)))
+
+
+;;; List connections mode
+
+(define-derived-mode eglot-list-connections-mode  tabulated-list-mode
+  "" "Eglot mode for listing server connections
+\\{eglot-list-connections-mode-map}"
+  (setq-local tabulated-list-format
+              `[("Language server" 16) ("Project name" 16) ("Modes handled" 16)])
+  (tabulated-list-init-header))
+
+(defun eglot-list-connections ()
+  "List currently active Eglot connections."
+  (interactive)
+  (with-current-buffer
+      (get-buffer-create "*EGLOT connections*")
+    (let ((inhibit-read-only t))
+      (erase-buffer)
+      (eglot-list-connections-mode)
+      (setq-local tabulated-list-entries
+                  (mapcar
+                   (lambda (server)
+                     (list server
+                           `[,(or (plist-get (eglot--server-info server) :name)
+                                  (jsonrpc-name server))
+                             ,(eglot-project-nickname server)
+                             ,(mapconcat #'symbol-name
+                                         (eglot--major-modes server)
+                                         ", ")]))
+                   (cl-reduce #'append
+                              (hash-table-values eglot--servers-by-project))))
+      (revert-buffer)
+      (pop-to-buffer (current-buffer)))))
+
+
+;;; Hacks
+;;;
+;; FIXME: Although desktop.el compatibility is Emacs bug#56407, the
+;; optimal solution agreed to there is a bit more work than what I
+;; have time to right now.  See
+;; e.g. https://debbugs.gnu.org/cgi/bugreport.cgi?bug=bug%2356407#68.
+;; For now, just use `with-eval-after-load'
+(with-eval-after-load 'desktop
+  (add-to-list 'desktop-minor-mode-handlers '(eglot--managed-mode . ignore)))
+
+
+;;; Obsolete
+;;;
+
+(make-obsolete-variable 'eglot--managed-mode-hook
+                        'eglot-managed-mode-hook "1.6")
+(provide 'eglot)
+
+
+;;; Backend completion
+
+;; Written by Stefan Monnier circa 2016.  Something to move to
+;; minibuffer.el "ASAP" (with all the `eglot--lsp-' replaced by
+;; something else. The very same code already in SLY and stable for a
+;; long time.
+
+;; This "completion style" delegates all the work to the "programmable
+;; completion" table which is then free to implement its own
+;; completion style.  Typically this is used to take advantage of some
+;; external tool which already has its own completion system and
+;; doesn't give you efficient access to the prefix completion needed
+;; by other completion styles.  The table should recognize the symbols
+;; 'eglot--lsp-tryc and 'eglot--lsp-allc as ACTION, reply with
+;; (eglot--lsp-tryc COMP...) or (eglot--lsp-allc . (STRING . POINT)),
+;; accordingly.  tryc/allc names made akward/recognizable on purpose.
+
+(add-to-list 'completion-styles-alist
+             '(eglot--lsp-backend-style
+               eglot--lsp-backend-style-try-completion
+               eglot--lsp-backend-style-all-completions
+               "Ad-hoc completion style provided by the completion table."))
+
+(defun eglot--lsp-backend-style-call (op string table pred point)
+  (when (functionp table)
+    (let ((res (funcall table string pred (cons op point))))
+      (when (eq op (car-safe res))
+        (cdr res)))))
+
+(defun eglot--lsp-backend-style-try-completion (string table pred point)
+  (eglot--lsp-backend-style-call 'eglot--lsp-tryc string table pred point))
+
+(defun eglot--lsp-backend-style-all-completions (string table pred point)
+  (eglot--lsp-backend-style-call 'eglot--lsp-allc string table pred point))
+
+
+;; Local Variables:
+;; bug-reference-bug-regexp: "\\(github#\\([0-9]+\\)\\)"
+;; bug-reference-url-format: "https://github.com/joaotavora/eglot/issues/%s"
+;; checkdoc-force-docstrings-flag: nil
+;; End:
+
+;;; eglot.el ends here