Syntax properties and \_>

[Ralf Angeli]

Hello everybody,

for font locking in AUCTeX am trying to match strings like "\\",
"\\*", "\-" but also "\newpage" and similar with a single regular
expression.  I was trying to limit the match with help of \_> for
matching the empty string at the end of the strings.  This works for
all constructs except "\\" because the character ?\\ has escape
syntax.  Now I thought that placing a symbol syntax property onto the
second "\" would help, but it doesn't.  Here is an example:

(with-temp-buffer
  (insert "\\\\")
  (put-text-property (1- (point)) (point) 'syntax-table '(3))
  (newline)
  (goto-char (point-min))
  (let ((parse-sexp-lookup-properties t))
    (re-search-forward "\\\\\\\\\\_>" nil t)))

Upon executing it you should see that it returns nil.  But trying the
same example with "\\s_" instead of "\\\\\\\\\\_>" for the
`re-search-forward' statement returns a match.

Is this a bug in the way \_> is handled?  It doesn't seem to recognize
syntax properties because there is a match if the syntax for "\" is
changed with `(modify-syntax-entry ?\\ "_")' instead of setting a
syntax property.  Or am I doing something wrong?

-- 
Ralf