diff options
Diffstat (limited to 'doc/lispintro/emacs-lisp-intro.texi')
-rw-r--r-- | doc/lispintro/emacs-lisp-intro.texi | 48 |
1 files changed, 15 insertions, 33 deletions
diff --git a/doc/lispintro/emacs-lisp-intro.texi b/doc/lispintro/emacs-lisp-intro.texi index d00f36cda58..61e3154baa4 100644 --- a/doc/lispintro/emacs-lisp-intro.texi +++ b/doc/lispintro/emacs-lisp-intro.texi @@ -9116,8 +9116,8 @@ Lisp; it is written in C and is one of the primitives of the GNU Emacs system. Since it is very simple, I will digress briefly from Lisp and describe it here. -@c GNU Emacs 22 in /usr/local/src/emacs/src/editfns.c -@c the DEFUN for buffer-substring-no-properties +@c GNU Emacs 24 in src/editfns.c +@c the DEFUN for delete-and-extract-region @need 1500 Like many of the other Emacs primitives, @@ -9127,22 +9127,15 @@ like this: @smallexample @group -DEFUN ("buffer-substring-no-properties", Fbuffer_substring_no_properties, - Sbuffer_substring_no_properties, 2, 2, 0, - doc: /* Return the characters of part of the buffer, -without the text properties. -The two arguments START and END are character positions; -they can be in either order. */) - (start, end) - Lisp_Object start, end; +DEFUN ("delete-and-extract-region", Fdelete_and_extract_region, + Sdelete_and_extract_region, 2, 2, 0, + doc: /* Delete the text between START and END and return it. */) + (Lisp_Object start, Lisp_Object end) @{ - register int b, e; - validate_region (&start, &end); - b = XINT (start); - e = XINT (end); - - return make_buffer_string (b, e, 0); + if (XINT (start) == XINT (end)) + return empty_unibyte_string; + return del_range_1 (XINT (start), XINT (end), 1, 1); @} @end group @end smallexample @@ -9192,20 +9185,9 @@ and provides a prompt. @item The seventh part is a documentation string, just like the one for a -function written in Emacs Lisp, except that every newline must be -written explicitly as @samp{\n} followed by a backslash and carriage -return. - -@need 1000 -Thus, the first two lines of documentation for @code{goto-char} are -written like this: - -@smallexample -@group - "Set point to POSITION, a number or marker.\n\ -Beginning of buffer is position (point-min), end is (point-max)." -@end group -@end smallexample +function written in Emacs Lisp. This is written as a C comment. (When +you build Emacs, the program @command{lib-src/make-docfile} extracts +these comments and uses them to make the ``real'' documentation.) @end itemize @need 1200 @@ -9218,15 +9200,15 @@ consists of the following four lines: @group validate_region (&start, &end); if (XINT (start) == XINT (end)) - return build_string (""); + return empty_unibyte_string; return del_range_1 (XINT (start), XINT (end), 1, 1); @end group @end smallexample -The @code{validate_region} function checks whether the values +The @code{validate_region} function checks whether the values passed as the beginning and end of the region are the proper type and are within range. If the beginning and end positions are the same, -then return and empty string. +then return an empty string. The @code{del_range_1} function actually deletes the text. It is a complex function we will not look into. It updates the buffer and |