(Buffer Contents): Add filter-buffer-substring and buffer-substring-filters.

5 files changed, 84 insertions, 0 deletions

diff --git a/etc/NEWS b/etc/NEWS
index c3134d08880..8e85c86dde8 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -2436,6 +2436,17 @@ coding system.
 * New modes and packages in Emacs 22.1
 
 +++
+** The new package longlines.el provides a minor mode for editing text
+files composed of long lines, based on the `use-hard-newlines'
+mechanism.  The long lines are broken up by inserting soft newlines,
+which are automatically removed when saving the file to disk or
+copying into the kill ring, clipboard, etc.  By default, Longlines
+mode inserts soft newlines automatically during editing, a behavior
+referred to as "soft word wrap" in other text editors.  This is
+similar to Refill mode, but more reliable.  To turn the word wrap
+feature off, set `longlines-auto-wrap' to nil.
+
++++
 ** The new package conf-mode.el handles thousands of configuration files, with
 varying syntaxes for comments (;, #, //, /* */ or !), assignment (var = value,
 var : value, var value or keyword var value) and sections ([section] or
@@ -2712,6 +2723,17 @@ the command `undefined'.  (In earlier Emacs versions, it used
 * Lisp Changes in Emacs 22.1
 
 +++
+** The new function `filter-buffer-substring' extracts a buffer
+substring, passes it through a set of filter functions, and returns
+the filtered substring.  It is used instead of `buffer-substring' or
+`delete-and-extract-region' when copying text into a user-accessible
+data structure, like the kill-ring, X clipboard, or a register.  The
+list of filter function is specified by the new variable
+`buffer-substring-filters'.  For example, Longlines mode uses
+`buffer-substring-filters' to remove soft newlines from the copied
+text.
+
++++
 ** An element of buffer-undo-list can now have the form (apply FUNNAME
 . ARGS), where FUNNAME is a symbol other than t or nil.  That stands
 for a high-level change that should be undone by evaluating (apply
diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index e2cdac00334..2ff35b7344d 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,18 @@
+2005-03-29  Richard M. Stallman  <rms@gnu.org>
+
+        * simple.el (idle-update-delay): Move definition up.
+
+2005-03-29  Chong Yidong  <cyd@stupidchicken.com>
+
+        * longlines.el: New file.
+        
+        * simple.el (buffer-substring-filters): New variable.
+        (filter-buffer-substring): New function.
+        (kill-region, copy-region-as-kill): Use it.
+
+        * register.el (copy-to-register, append-to-register)
+        (prepend-to-register): Use filter-buffer-substring.
+
 2005-03-30  Nick Roberts  <nickrob@snap.net.nz>
 
         * progmodes/gud.el (gdb): (Re)-initialise gud-filter-pending-text.      
diff --git a/lispref/ChangeLog b/lispref/ChangeLog
index 232e992e658..7f22ad2e485 100644
--- a/lispref/ChangeLog
+++ b/lispref/ChangeLog
@@ -1,3 +1,8 @@
+2005-03-29  Chong Yidong  <cyd@stupidchicken.com>
+
+        * text.texi (Buffer Contents): Add filter-buffer-substring and
+        buffer-substring-filters.
+
 2005-03-26  Chong Yidong  <cyd@stupidchicken.com>
 
         * anti.texi (Antinews): Mention `G' interactive code.
diff --git a/lispref/text.texi b/lispref/text.texi
index e300b345454..1d4dc0fce8a 100644
--- a/lispref/text.texi
+++ b/lispref/text.texi
@@ -207,6 +207,41 @@ This is like @code{buffer-substring}, except that it does not copy text
 properties, just the characters themselves.  @xref{Text Properties}.
 @end defun
 
+@defun filter-buffer-substring start end &optional delete
+This function passes the buffer text between @var{start} and @var{end}
+through the filter functions specified by the variable
+@code{buffer-substring-filters}, and returns the value from the last
+filter function.  If @code{buffer-substring-filters} is @code{nil},
+the value is the unaltered text from the buffer, what
+@code{buffer-substring} would return.
+
+If @var{delete} is non-@code{nil}, this function deletes the text
+between @var{start} and @var{end} after copying it, like
+@code{delete-and-extract-region}.
+
+Lisp code should use this function instead of @code{buffer-substring}
+or @code{delete-and-extract-region} when copying into user-accessible
+data structures such as the kill-ring, X clipboard, and registers.
+Major and minor modes can add functions to
+@code{buffer-substring-filters} to alter such text as it is copied out
+of the buffer.
+@end defun
+
+@defvar buffer-substring-filters
+This variable should be a list of functions that accept a single
+argument, a string, and return a string.
+@code{filter-buffer-substring} passes the buffer substring to the
+first function in this list, and the return value of each function is
+passed to the next function.  The return value of the last function is
+used as the return value of @code{filter-buffer-substring}.
+
+As a special convention, point is set to the start of the buffer text
+being operated on (i.e., the @var{start} argument for
+@code{filter-buffer-substring}) before these functions are called.
+
+If this variable is @code{nil}, no filtering is performed.
+@end defvar
+
 @defun buffer-string
 This function returns the contents of the entire accessible portion of
 the current buffer as a string.  It is equivalent to
diff --git a/man/ChangeLog b/man/ChangeLog
index ec6fbbdcced..c67256c5ec9 100644
--- a/man/ChangeLog
+++ b/man/ChangeLog
@@ -1,3 +1,10 @@
+2005-03-29  Chong Yidong  <cyd@stupidchicken.com>
+
+        * text.texi (Refill): Refer to Long Lines Mode.
+        (Longlines): New node.
+        (Auto Fill): Don't index "word wrap" here.
+        (Filling): Add Longlines to menu.
+        
 2005-03-29  Richard M. Stallman  <rms@gnu.org>
 
         * xresources.texi: Minor fixes.