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* emacs-lisp-intro.texi (Digression into C): Update example.

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Glenn Morris 2013-03-02 18:34:48 -08:00
parent 9bed73f343
commit 2d7d23256f
2 changed files with 19 additions and 33 deletions
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4
doc/lispintro/ChangeLog
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@ -1,3 +1,7 @@
2013-03-03 Glenn Morris <rgm@gnu.org>
* emacs-lisp-intro.texi (Digression into C): Update example.
2012-12-22 Glenn Morris <rgm@gnu.org>
* Makefile.in (srcs): New variable, adding doclicense.texi.

48
doc/lispintro/emacs-lisp-intro.texi
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@ -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