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view lisp/syntax.el @ 665:fdefd0186b75
[xemacs-hg @ 2001-09-20 06:28:42 by ben]
The great integral types renaming.
The purpose of this is to rationalize the names used for various
integral types, so that they match their intended uses and follow
consist conventions, and eliminate types that were not semantically
different from each other.
The conventions are:
-- All integral types that measure quantities of anything are
signed. Some people disagree vociferously with this, but their
arguments are mostly theoretical, and are vastly outweighed by
the practical headaches of mixing signed and unsigned values,
and more importantly by the far increased likelihood of
inadvertent bugs: Because of the broken "viral" nature of
unsigned quantities in C (operations involving mixed
signed/unsigned are done unsigned, when exactly the opposite is
nearly always wanted), even a single error in declaring a
quantity unsigned that should be signed, or even the even more
subtle error of comparing signed and unsigned values and
forgetting the necessary cast, can be catastrophic, as
comparisons will yield wrong results. -Wsign-compare is turned
on specifically to catch this, but this tends to result in a
great number of warnings when mixing signed and unsigned, and
the casts are annoying. More has been written on this
elsewhere.
-- All such quantity types just mentioned boil down to EMACS_INT,
which is 32 bits on 32-bit machines and 64 bits on 64-bit
machines. This is guaranteed to be the same size as Lisp
objects of type `int', and (as far as I can tell) of size_t
(unsigned!) and ssize_t. The only type below that is not an
EMACS_INT is Hashcode, which is an unsigned value of the same
size as EMACS_INT.
-- Type names should be relatively short (no more than 10
characters or so), with the first letter capitalized and no
underscores if they can at all be avoided.
-- "count" == a zero-based measurement of some quantity. Includes
sizes, offsets, and indexes.
-- "bpos" == a one-based measurement of a position in a buffer.
"Charbpos" and "Bytebpos" count text in the buffer, rather than
bytes in memory; thus Bytebpos does not directly correspond to
the memory representation. Use "Membpos" for this.
-- "Char" refers to internal-format characters, not to the C type
"char", which is really a byte.
-- For the actual name changes, see the script below.
I ran the following script to do the conversion. (NOTE: This script
is idempotent. You can safely run it multiple times and it will
not screw up previous results -- in fact, it will do nothing if
nothing has changed. Thus, it can be run repeatedly as necessary
to handle patches coming in from old workspaces, or old branches.)
There are two tags, just before and just after the change:
`pre-integral-type-rename' and `post-integral-type-rename'. When
merging code from the main trunk into a branch, the best thing to
do is first merge up to `pre-integral-type-rename', then apply the
script and associated changes, then merge from
`post-integral-type-change' to the present. (Alternatively, just do
the merging in one operation; but you may then have a lot of
conflicts needing to be resolved by hand.)
Script `fixtypes.sh' follows:
----------------------------------- cut ------------------------------------
files="*.[ch] s/*.h m/*.h config.h.in ../configure.in Makefile.in.in ../lib-src/*.[ch] ../lwlib/*.[ch]"
gr Memory_Count Bytecount $files
gr Lstream_Data_Count Bytecount $files
gr Element_Count Elemcount $files
gr Hash_Code Hashcode $files
gr extcount bytecount $files
gr bufpos charbpos $files
gr bytind bytebpos $files
gr memind membpos $files
gr bufbyte intbyte $files
gr Extcount Bytecount $files
gr Bufpos Charbpos $files
gr Bytind Bytebpos $files
gr Memind Membpos $files
gr Bufbyte Intbyte $files
gr EXTCOUNT BYTECOUNT $files
gr BUFPOS CHARBPOS $files
gr BYTIND BYTEBPOS $files
gr MEMIND MEMBPOS $files
gr BUFBYTE INTBYTE $files
gr MEMORY_COUNT BYTECOUNT $files
gr LSTREAM_DATA_COUNT BYTECOUNT $files
gr ELEMENT_COUNT ELEMCOUNT $files
gr HASH_CODE HASHCODE $files
----------------------------------- cut ------------------------------------
`fixtypes.sh' is a Bourne-shell script; it uses 'gr':
----------------------------------- cut ------------------------------------
#!/bin/sh
# Usage is like this:
# gr FROM TO FILES ...
# globally replace FROM with TO in FILES. FROM and TO are regular expressions.
# backup files are stored in the `backup' directory.
from="$1"
to="$2"
shift 2
echo ${1+"$@"} | xargs global-replace "s/$from/$to/g"
----------------------------------- cut ------------------------------------
`gr' in turn uses a Perl script to do its real work,
`global-replace', which follows:
----------------------------------- cut ------------------------------------
: #-*- Perl -*-
### global-modify --- modify the contents of a file by a Perl expression
## Copyright (C) 1999 Martin Buchholz.
## Copyright (C) 2001 Ben Wing.
## Authors: Martin Buchholz <martin@xemacs.org>, Ben Wing <ben@xemacs.org>
## Maintainer: Ben Wing <ben@xemacs.org>
## Current Version: 1.0, May 5, 2001
# This program 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 2, or (at your option)
# any later version.
#
# This program 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 XEmacs; see the file COPYING. If not, write to the Free
# Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
# 02111-1307, USA.
eval 'exec perl -w -S $0 ${1+"$@"}'
if 0;
use strict;
use FileHandle;
use Carp;
use Getopt::Long;
use File::Basename;
(my $myName = $0) =~ s@.*/@@; my $usage="
Usage: $myName [--help] [--backup-dir=DIR] [--line-mode] [--hunk-mode]
PERLEXPR FILE ...
Globally modify a file, either line by line or in one big hunk.
Typical usage is like this:
[with GNU print, GNU xargs: guaranteed to handle spaces, quotes, etc.
in file names]
find . -name '*.[ch]' -print0 | xargs -0 $0 's/\bCONST\b/const/g'\n
[with non-GNU print, xargs]
find . -name '*.[ch]' -print | xargs $0 's/\bCONST\b/const/g'\n
The file is read in, either line by line (with --line-mode specified)
or in one big hunk (with --hunk-mode specified; it's the default), and
the Perl expression is then evalled with \$_ set to the line or hunk of
text, including the terminating newline if there is one. It should
destructively modify the value there, storing the changed result in \$_.
Files in which any modifications are made are backed up to the directory
specified using --backup-dir, or to `backup' by default. To disable this,
use --backup-dir= with no argument.
Hunk mode is the default because it is MUCH MUCH faster than line-by-line.
Use line-by-line only when it matters, e.g. you want to do a replacement
only once per line (the default without the `g' argument). Conversely,
when using hunk mode, *ALWAYS* use `g'; otherwise, you will only make one
replacement in the entire file!
";
my %options = ();
$Getopt::Long::ignorecase = 0;
&GetOptions (
\%options,
'help', 'backup-dir=s', 'line-mode', 'hunk-mode',
);
die $usage if $options{"help"} or @ARGV <= 1;
my $code = shift;
die $usage if grep (-d || ! -w, @ARGV);
sub SafeOpen {
open ((my $fh = new FileHandle), $_[0]);
confess "Can't open $_[0]: $!" if ! defined $fh;
return $fh;
}
sub SafeClose {
close $_[0] or confess "Can't close $_[0]: $!";
}
sub FileContents {
my $fh = SafeOpen ("< $_[0]");
my $olddollarslash = $/;
local $/ = undef;
my $contents = <$fh>;
$/ = $olddollarslash;
return $contents;
}
sub WriteStringToFile {
my $fh = SafeOpen ("> $_[0]");
binmode $fh;
print $fh $_[1] or confess "$_[0]: $!\n";
SafeClose $fh;
}
foreach my $file (@ARGV) {
my $changed_p = 0;
my $new_contents = "";
if ($options{"line-mode"}) {
my $fh = SafeOpen $file;
while (<$fh>) {
my $save_line = $_;
eval $code;
$changed_p = 1 if $save_line ne $_;
$new_contents .= $_;
}
} else {
my $orig_contents = $_ = FileContents $file;
eval $code;
if ($_ ne $orig_contents) {
$changed_p = 1;
$new_contents = $_;
}
}
if ($changed_p) {
my $backdir = $options{"backup-dir"};
$backdir = "backup" if !defined ($backdir);
if ($backdir) {
my ($name, $path, $suffix) = fileparse ($file, "");
my $backfulldir = $path . $backdir;
my $backfile = "$backfulldir/$name";
mkdir $backfulldir, 0755 unless -d $backfulldir;
print "modifying $file (original saved in $backfile)\n";
rename $file, $backfile;
}
WriteStringToFile ($file, $new_contents);
}
}
----------------------------------- cut ------------------------------------
In addition to those programs, I needed to fix up a few other
things, particularly relating to the duplicate definitions of
types, now that some types merged with others. Specifically:
1. in lisp.h, removed duplicate declarations of Bytecount. The
changed code should now look like this: (In each code snippet
below, the first and last lines are the same as the original, as
are all lines outside of those lines. That allows you to locate
the section to be replaced, and replace the stuff in that
section, verifying that there isn't anything new added that
would need to be kept.)
--------------------------------- snip -------------------------------------
/* Counts of bytes or chars */
typedef EMACS_INT Bytecount;
typedef EMACS_INT Charcount;
/* Counts of elements */
typedef EMACS_INT Elemcount;
/* Hash codes */
typedef unsigned long Hashcode;
/* ------------------------ dynamic arrays ------------------- */
--------------------------------- snip -------------------------------------
2. in lstream.h, removed duplicate declaration of Bytecount.
Rewrote the comment about this type. The changed code should
now look like this:
--------------------------------- snip -------------------------------------
#endif
/* The have been some arguments over the what the type should be that
specifies a count of bytes in a data block to be written out or read in,
using Lstream_read(), Lstream_write(), and related functions.
Originally it was long, which worked fine; Martin "corrected" these to
size_t and ssize_t on the grounds that this is theoretically cleaner and
is in keeping with the C standards. Unfortunately, this practice is
horribly error-prone due to design flaws in the way that mixed
signed/unsigned arithmetic happens. In fact, by doing this change,
Martin introduced a subtle but fatal error that caused the operation of
sending large mail messages to the SMTP server under Windows to fail.
By putting all values back to be signed, avoiding any signed/unsigned
mixing, the bug immediately went away. The type then in use was
Lstream_Data_Count, so that it be reverted cleanly if a vote came to
that. Now it is Bytecount.
Some earlier comments about why the type must be signed: This MUST BE
SIGNED, since it also is used in functions that return the number of
bytes actually read to or written from in an operation, and these
functions can return -1 to signal error.
Note that the standard Unix read() and write() functions define the
count going in as a size_t, which is UNSIGNED, and the count going
out as an ssize_t, which is SIGNED. This is a horrible design
flaw. Not only is it highly likely to lead to logic errors when a
-1 gets interpreted as a large positive number, but operations are
bound to fail in all sorts of horrible ways when a number in the
upper-half of the size_t range is passed in -- this number is
unrepresentable as an ssize_t, so code that checks to see how many
bytes are actually written (which is mandatory if you are dealing
with certain types of devices) will get completely screwed up.
--ben
*/
typedef enum lstream_buffering
--------------------------------- snip -------------------------------------
3. in dumper.c, there are four places, all inside of switch()
statements, where XD_BYTECOUNT appears twice as a case tag. In
each case, the two case blocks contain identical code, and you
should *REMOVE THE SECOND* and leave the first.
| author | ben |
|---|---|
| date | Thu, 20 Sep 2001 06:31:11 +0000 |
| parents | 7039e6323819 |
| children | 2f31c7aa4e96 |
line wrap: on
line source
;; syntax.el --- Syntax-table hacking stuff, moved from syntax.c ;; Copyright (C) 1993, 1997 Free Software Foundation, Inc. ;; Copyright (C) 1995 Sun Microsystems. ;; This file is part of XEmacs. ;; XEmacs 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 2, or (at your option) ;; any later version. ;; XEmacs 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 XEmacs; see the file COPYING. If not, write to the ;; Free Software Foundation, 59 Temple Place - Suite 330, ;; Boston, MA 02111-1307, USA. ;;; Synched up with: FSF 19.28. ;;; Commentary: ;; This file is dumped with XEmacs. ;; Note: FSF does not have a file syntax.el. This stuff is ;; in syntax.c. See comments there about not merging past 19.28. ;; Significantly hacked upon by Ben Wing. ;;; Code: (defun make-syntax-table (&optional oldtable) "Return a new syntax table. It inherits all characters from the standard syntax table." (make-char-table 'syntax)) (defun simple-set-syntax-entry (char spec table) (put-char-table char spec table)) (defun char-syntax-from-code (code) "Extract the syntax designator from the internal syntax code CODE. CODE is the value actually contained in the syntax table." (if (consp code) (setq code (car code))) (aref (syntax-designator-chars) (logand code 127))) (defun set-char-syntax-in-code (code desig) "Return a new internal syntax code whose syntax designator is DESIG. Other characteristics are the same as in CODE." (let ((newcode (if (consp code) (car code) code))) (setq newcode (logior (string-match (regexp-quote (char-to-string desig)) (syntax-designator-chars)) (logand newcode (lognot 127)))) (if (consp code) (cons newcode (cdr code)) newcode))) (defun syntax-code-to-string (code) "Return a string equivalent to internal syntax code CODE. The string can be passed to `modify-syntax-entry'. If CODE is invalid, return nil." (let ((match (and (consp code) (cdr code))) (codes (syntax-designator-chars))) (if (consp code) (setq code (car code))) (if (or (not (integerp code)) (> (logand code 127) (length codes))) nil (with-output-to-string (let* ((spec (elt codes (logand code 127))) (b3 (lsh code -16)) (start1 (/= 0 (logand b3 128))) ;logtest! (start1b (/= 0 (logand b3 64))) (start2 (/= 0 (logand b3 32))) (start2b (/= 0 (logand b3 16))) (end1 (/= 0 (logand b3 8))) (end1b (/= 0 (logand b3 4))) (end2 (/= 0 (logand b3 2))) (end2b (/= 0 (logand b3 1))) (prefix (/= 0 (logand code 128))) (single-char-p (or (= spec ?<) (= spec ?>))) ) (write-char spec) (write-char (if match match 32)) ;;; (if start1 (if single-char-p (write-char ?a) (write-char ?1))) (if start1 (if single-char-p (write-char ? ) (write-char ?1))) (if start2 (write-char ?2)) ;;; (if end1 (if single-char-p (write-char ?a) (write-char ?3))) (if end1 (if single-char-p (write-char ? ) (write-char ?3))) (if end2 (write-char ?4)) (if start1b (if single-char-p (write-char ?b) (write-char ?5))) (if start2b (write-char ?6)) (if end1b (if single-char-p (write-char ?b) (write-char ?7))) (if end2b (write-char ?8)) (if prefix (write-char ?p))))))) (defun syntax-string-to-code (string) "Return the internal syntax code equivalent to STRING. STRING should be something acceptable as the second argument to `modify-syntax-entry'. If STRING is invalid, signal an error." (let* ((bflag nil) (b3 0) (ch0 (aref string 0)) (len (length string)) (code (string-match (regexp-quote (char-to-string ch0)) (syntax-designator-chars))) (i 2) ch) (or code (error "Invalid syntax designator: %S" string)) (while (< i len) (setq ch (aref string i)) (incf i) (case ch (?1 (setq b3 (logior b3 128))) (?2 (setq b3 (logior b3 32))) (?3 (setq b3 (logior b3 8))) (?4 (setq b3 (logior b3 2))) (?5 (setq b3 (logior b3 64))) (?6 (setq b3 (logior b3 16))) (?7 (setq b3 (logior b3 4))) (?8 (setq b3 (logior b3 1))) (?a (case ch0 (?< (setq b3 (logior b3 128))) (?> (setq b3 (logior b3 8))))) (?b (case ch0 (?< (setq b3 (logior b3 64) bflag t)) (?> (setq b3 (logior b3 4) bflag t)))) (?p (setq code (logior code (lsh 1 7)))) (?\ nil) ;; ignore for compatibility (otherwise (error "Invalid syntax description flag: %S" string)))) ;; default single char style if `b' has not been seen (if (not bflag) (case ch0 (?< (setq b3 (logior b3 128))) (?> (setq b3 (logior b3 8))))) (setq code (logior code (lsh b3 16))) (if (and (> len 1) ;; tough luck if you want to make space a paren! (/= (aref string 1) ?\ )) (setq code (cons code (aref string 1)))) code)) (defun modify-syntax-entry (char-range spec &optional syntax-table) "Set syntax for the characters CHAR-RANGE according to string SPEC. CHAR-RANGE is a single character or a range of characters, as per `put-char-table'. The syntax is changed only for SYNTAX-TABLE, which defaults to the current buffer's syntax table. The first character of SPEC should be one of the following: Space whitespace syntax. w word constituent. _ symbol constituent. . punctuation. \( open-parenthesis. \) close-parenthesis. \" string quote. \\ character-quote. $ paired delimiter. ' expression quote or prefix operator. < comment starter. > comment ender. / character-quote. @ inherit from `standard-syntax-table'. Only single-character comment start and end sequences are represented thus. Two-character sequences are represented as described below. The second character of SPEC is the matching parenthesis, used only if the first character is `(' or `)'. Any additional characters are flags. Defined flags are the characters 1, 2, 3, 4, 5, 6, 7, 8, p, a, and b. 1 means C is the first of a two-char comment start sequence of style a. 2 means C is the second character of such a sequence. 3 means C is the first of a two-char comment end sequence of style a. 4 means C is the second character of such a sequence. 5 means C is the first of a two-char comment start sequence of style b. 6 means C is the second character of such a sequence. 7 means C is the first of a two-char comment end sequence of style b. 8 means C is the second character of such a sequence. p means C is a prefix character for `backward-prefix-chars'; such characters are treated as whitespace when they occur between expressions. a means C is comment starter or comment ender for comment style a (default) b means C is comment starter or comment ender for comment style b." (interactive ;; I really don't know why this is interactive ;; help-form should at least be made useful while reading the second arg "cSet syntax for character: \nsSet syntax for %c to: ") (simple-set-syntax-entry char-range (syntax-string-to-code spec) (cond ((syntax-table-p syntax-table) syntax-table) ((null syntax-table) (syntax-table)) (t (wrong-type-argument 'syntax-table-p syntax-table)))) nil) (defun map-syntax-table (__function __syntax_table &optional __range) "Map FUNCTION over entries in SYNTAX-TABLE, collapsing inheritance. This is similar to `map-char-table', but works only on syntax tables, and collapses any entries that call for inheritance by invisibly substituting the inherited values from the standard syntax table." (check-argument-type 'syntax-table-p __syntax_table) (map-char-table #'(lambda (__key __value) (if (eq ?@ (char-syntax-from-code __value)) (map-char-table #'(lambda (__key __value) (funcall __function __key __value)) (standard-syntax-table) __key) (funcall __function __key __value))) __syntax_table __range)) ;(defun test-xm () ; (let ((o (copy-syntax-table)) ; (n (copy-syntax-table)) ; (codes (syntax-designator-chars)) ; (flags "12345678abp")) ; (while t ; (let ((spec (concat (char-to-string (elt codes ; (random (length codes)))))) ; (if (= (random 4) 0) ; "b" ; " ") ; (let* ((n (random 4)) ; (s (make-string n 0))) ; (while (> n 0) ; (setq n (1- n)) ; (aset s n (aref flags (random (length flags))))) ; s)))) ; (message "%S..." spec) ; (modify-syntax-entry ?a spec o) ; (xmodify-syntax-entry ?a spec n) ; (or (= (aref o ?a) (aref n ?a)) ; (error "%s" ; (format "fucked with %S: %x %x" ; spec (aref o ?a) (aref n ?a)))))))) (defun describe-syntax-table (table stream) (let (first-char last-char prev-val (describe-one (if (featurep 'mule) #'(lambda (first last value stream) (if (equal first last) (cond ((vectorp first) (princ (format "%s, row %d\t" (declare-fboundp (charset-name (aref first 0))) (aref first 1)) stream)) ((symbolp first) (princ first stream) (princ "\t" stream)) (t (princ (text-char-description first) stream) (princ "\t" stream))) (cond ((vectorp first) (princ (format "%s, rows %d .. %d\t" (declare-fboundp (charset-name (aref first 0))) (aref first 1) (aref last 1)) stream)) ((symbolp first) (princ (format "%s .. %s\t" first last) stream)) (t (princ (format "%s .. %s\t" (text-char-description first) (text-char-description last)) stream)))) (describe-syntax-code value stream)) #'(lambda (first last value stream) (let* ((tem (text-char-description first)) (pos (length tem)) ;;(limit (cond ((numberp ctl-arrow) ctl-arrow) ;; ((memq ctl-arrow '(t nil)) 256) ;; (t 160))) ) (princ tem stream) (if (> last first) (progn (princ " .. " stream) (setq tem (text-char-description last)) (princ tem stream) (setq pos (+ pos (length tem) 4)))) (while (progn (write-char ?\ stream) (setq pos (1+ pos)) (< pos 16)))) (describe-syntax-code value stream))))) (map-syntax-table #'(lambda (range value) (cond ((not first-char) (setq first-char range last-char range prev-val value)) ((and (equal value prev-val) (or (and (characterp range) (characterp first-char) (or (not (featurep 'mule)) (eq (declare-fboundp (char-charset range)) (declare-fboundp (char-charset first-char)))) (= (char-int last-char) (1- (char-int range)))) (and (vectorp range) (vectorp first-char) (eq (aref range 0) (aref first-char 0)) (= (aref last-char 1) (1- (aref range 1)))))) (setq last-char range)) (t (funcall describe-one first-char last-char prev-val stream) (setq first-char range last-char range prev-val value))) nil) table) (if first-char (funcall describe-one first-char last-char prev-val stream)))) (defun describe-syntax-code (code stream) (let ((match (and (consp code) (cdr code))) (invalid (gettext "**invalid**")) ;(empty "") ;constants (standard-output (or stream standard-output)) ;; #### I18N3 should temporarily set buffer to output-translatable (in #'(lambda (string) (princ ",\n\t\t\t\t ") (princ string))) (syntax-string (syntax-code-to-string code))) (if (consp code) (setq code (car code))) (if (null syntax-string) (princ invalid) (princ syntax-string) (princ "\tmeaning: ") (princ (aref ["whitespace" "punctuation" "word-constituent" "symbol-constituent" "open-paren" "close-paren" "expression-prefix" "string-quote" "paired-delimiter" "escape" "character-quote" "comment-begin" "comment-end" "inherit" "extended-word-constituent"] (logand code 127))) (if match (progn (princ ", matches ") (princ (text-char-description match)))) (let* ((spec (elt syntax-string 0)) (b3 (lsh code -16)) (start1 (/= 0 (logand b3 128))) ;logtest! (start1b (/= 0 (logand b3 64))) (start2 (/= 0 (logand b3 32))) (start2b (/= 0 (logand b3 16))) (end1 (/= 0 (logand b3 8))) (end1b (/= 0 (logand b3 4))) (end2 (/= 0 (logand b3 2))) (end2b (/= 0 (logand b3 1))) (prefix (/= 0 (logand code 128))) (single-char-p (or (= spec ?<) (= spec ?>)))) (if start1 (if single-char-p (princ ", style A") (funcall in (gettext "first character of comment-start sequence A")))) (if start2 (funcall in (gettext "second character of comment-start sequence A"))) (if end1 (if single-char-p (princ ", style A") (funcall in (gettext "first character of comment-end sequence A")))) (if end2 (funcall in (gettext "second character of comment-end sequence A"))) (if start1b (if single-char-p (princ ", style B") (funcall in (gettext "first character of comment-start sequence B")))) (if start2b (funcall in (gettext "second character of comment-start sequence B"))) (if end1b (if single-char-p (princ ", style B") (funcall in (gettext "first character of comment-end sequence B")))) (if end2b (funcall in (gettext "second character of comment-end sequence B"))) (if prefix (funcall in (gettext "prefix character for `backward-prefix-chars'")))) (terpri stream)))) (defun symbol-near-point () "Return the first textual item to the nearest point." (interactive) ;alg stolen from etag.el (save-excursion (if (or (bobp) (not (memq (char-syntax (char-before)) '(?w ?_)))) (while (not (looking-at "\\sw\\|\\s_\\|\\'")) (forward-char 1))) (while (looking-at "\\sw\\|\\s_") (forward-char 1)) (if (re-search-backward "\\sw\\|\\s_" nil t) (regexp-quote (progn (forward-char 1) (buffer-substring (point) (progn (forward-sexp -1) (while (looking-at "\\s'") (forward-char 1)) (point))))) nil))) ;;; syntax.el ends here