4 files changed, 85 insertions, 45 deletions

diff --git a/lisp/eshell/em-basic.el b/lisp/eshell/em-basic.el
index 27b343ad398..ba868cee59e 100644
--- a/lisp/eshell/em-basic.el
+++ b/lisp/eshell/em-basic.el
@@ -82,7 +82,11 @@ equivalent of `echo' can always be achieved by using `identity'."
 It returns a formatted value that should be passed to `eshell-print'
 or `eshell-printn' for display."
   (if eshell-plain-echo-behavior
-      (concat (apply 'eshell-flatten-and-stringify args) "\n")
+      (progn
+        ;; If the output does not end in a newline, do not emit one.
+        (setq eshell-ensure-newline-p nil)
+        (concat (apply #'eshell-flatten-and-stringify args)
+                (when output-newline "\n")))
     (let ((value
            (cond
             ((= (length args) 0) "")
@@ -109,18 +113,33 @@ or `eshell-printn' for display."
   "Implementation of `echo'.  See `eshell-plain-echo-behavior'."
   (eshell-eval-using-options
    "echo" args
-   '((?n nil nil output-newline "terminate with a newline")
-     (?h "help" nil nil "output this help screen")
+   '((?n nil (nil) output-newline
+         "do not output the trailing newline")
+     (?N nil (t)   output-newline
+         "terminate with a newline")
+     (?E nil nil   _disable-escapes
+         "don't interpret backslash escapes (default)")
+     (?h "help" nil nil
+         "output this help screen")
      :preserve-args
-     :usage "[-n] [object]")
-   (eshell-echo args output-newline)))
+     :usage "[OPTION]... [OBJECT]...")
+   (if eshell-plain-echo-behavior
+       (eshell-echo args (if output-newline (car output-newline) t))
+     ;; In Emacs 28.1 and earlier, "-n" was used to add a newline to
+     ;; non-plain echo in Eshell.  This caused confusion due to "-n"
+     ;; generally having the opposite meaning for echo.  Retain this
+     ;; compatibility for the time being.  For more info, see
+     ;; bug#27361.
+     (when (equal output-newline '(nil))
+       (display-warning
+        :warning "To terminate with a newline, you should use -N instead."))
+     (eshell-echo args output-newline))))
 
 (defun eshell/printnl (&rest args)
-  "Print out each of the arguments, separated by newlines."
+  "Print out each of the arguments as strings, separated by newlines."
   (let ((elems (flatten-tree args)))
-    (while elems
-      (eshell-printn (eshell-echo (list (car elems))))
-      (setq elems (cdr elems)))))
+    (dolist (elem elems)
+      (eshell-printn (eshell-stringify elem)))))
 
 (defun eshell/listify (&rest args)
   "Return the argument(s) as a single list."
diff --git a/lisp/eshell/em-script.el b/lisp/eshell/em-script.el
index e8459513f39..e0bcd8b099f 100644
--- a/lisp/eshell/em-script.el
+++ b/lisp/eshell/em-script.el
@@ -113,27 +113,13 @@ Comments begin with `#'."
 
 (defun eshell/source (&rest args)
   "Source a file in a subshell environment."
-  (eshell-eval-using-options
-   "source" args
-   '((?h "help" nil nil "show this usage screen")
-     :show-usage
-     :usage "FILE [ARGS]
-Invoke the Eshell commands in FILE in a subshell, binding ARGS to $1,
-$2, etc.")
-   (eshell-source-file (car args) (cdr args) t)))
+  (eshell-source-file (car args) (cdr args) t))
 
 (put 'eshell/source 'eshell-no-numeric-conversions t)
 
 (defun eshell/. (&rest args)
   "Source a file in the current environment."
-  (eshell-eval-using-options
-   "." args
-   '((?h "help" nil nil "show this usage screen")
-     :show-usage
-     :usage "FILE [ARGS]
-Invoke the Eshell commands in FILE within the current shell
-environment, binding ARGS to $1, $2, etc.")
-   (eshell-source-file (car args) (cdr args))))
+  (eshell-source-file (car args) (cdr args)))
 
 (put 'eshell/. 'eshell-no-numeric-conversions t)
 
diff --git a/lisp/eshell/esh-cmd.el b/lisp/eshell/esh-cmd.el
index a2d7d9431a9..04d65df4f33 100644
--- a/lisp/eshell/esh-cmd.el
+++ b/lisp/eshell/esh-cmd.el
@@ -107,6 +107,7 @@
 (require 'esh-module)
 (require 'esh-io)
 (require 'esh-ext)
+(require 'generator)
 
 (eval-when-compile
   (require 'cl-lib)
@@ -903,21 +904,55 @@ at the moment are:
   "Completion for the `debug' command."
   (while (pcomplete-here '("errors" "commands"))))
 
+(iter-defun eshell--find-subcommands (haystack)
+  "Recursively search for subcommand forms in HAYSTACK.
+This yields the SUBCOMMANDs when found in forms like
+\"(eshell-as-subcommand SUBCOMMAND)\"."
+  (dolist (elem haystack)
+    (cond
+     ((eq (car-safe elem) 'eshell-as-subcommand)
+      (iter-yield (cdr elem)))
+     ((listp elem)
+      (iter-yield-from (eshell--find-subcommands elem))))))
+
+(defun eshell--invoke-command-directly (command)
+  "Determine whether the given COMMAND can be invoked directly.
+COMMAND should be a non-top-level Eshell command in parsed form.
+
+A command can be invoked directly if all of the following are true:
+
+* The command is of the form
+  \"(eshell-trap-errors (eshell-named-command NAME ARGS))\",
+  where ARGS is optional.
+
+* NAME is a string referring to an alias function and isn't a
+  complex command (see `eshell-complex-commands').
+
+* Any subcommands in ARGS can also be invoked directly."
+  (when (and (eq (car command) 'eshell-trap-errors)
+             (eq (car (cadr command)) 'eshell-named-command))
+    (let ((name (cadr (cadr command)))
+          (args (cdr-safe (nth 2 (cadr command)))))
+      (and name (stringp name)
+           (not (member name eshell-complex-commands))
+           (catch 'simple
+             (dolist (pred eshell-complex-commands t)
+               (when (and (functionp pred)
+                          (funcall pred name))
+                 (throw 'simple nil))))
+           (eshell-find-alias-function name)
+           (catch 'indirect-subcommand
+             (iter-do (subcommand (eshell--find-subcommands args))
+               (unless (eshell--invoke-command-directly subcommand)
+                 (throw 'indirect-subcommand nil)))
+             t)))))
+
 (defun eshell-invoke-directly (command)
-  (let ((base (cadr (nth 2 (nth 2 (cadr command))))) name)
-    (if (and (eq (car base) 'eshell-trap-errors)
-             (eq (car (cadr base)) 'eshell-named-command))
-        (setq name (cadr (cadr base))))
-    (and name (stringp name)
-         (not (member name eshell-complex-commands))
-         (catch 'simple
-           (progn
-            (dolist (pred eshell-complex-commands)
-              (if (and (functionp pred)
-                       (funcall pred name))
-                  (throw 'simple nil)))
-            t))
-         (eshell-find-alias-function name))))
+  "Determine whether the given COMMAND can be invoked directly.
+COMMAND should be a top-level Eshell command in parsed form, as
+produced by `eshell-parse-command'."
+  (let ((base (cadr (nth 2 (nth 2 (cadr command))))))
+    (eshell--invoke-command-directly base)))
 
 (defun eshell-eval-command (command &optional input)
   "Evaluate the given COMMAND iteratively."
diff --git a/lisp/eshell/esh-opt.el b/lisp/eshell/esh-opt.el
index bba1c4ad25d..c802bee3af5 100644
--- a/lisp/eshell/esh-opt.el
+++ b/lisp/eshell/esh-opt.el
@@ -257,12 +257,12 @@ triggered to say that the switch is unrecognized."
         remaining
       (let ((extcmd (memq ':external options)))
         (when extcmd
-          (setq extcmd (eshell-search-path (cadr extcmd)))
-          (if extcmd
-              (throw 'eshell-ext-command extcmd)
-            (error (if (characterp (car switch)) "%s: unrecognized option -%c"
-                     "%s: unrecognized option --%s")
-                   name (car switch))))))))
+          (setq extcmd (eshell-search-path (cadr extcmd))))
+        (if extcmd
+            (throw 'eshell-ext-command extcmd)
+          (error (if (characterp (car switch)) "%s: unrecognized option -%c"
+                   "%s: unrecognized option --%s")
+                 name (car switch)))))))
 
 (defun eshell--process-args (name args options)
   "Process the given ARGS using OPTIONS."