bug#11953: 23.4; tex-mode does not fontify \url{foo/$(bar)} correctly

[Stefan Monnier]

>    The latex-mode fontifier is not aware that the (nonstandard)
>    \url{...} and \path{...} commands should have their contents treated
>    as if verbatim.  Here's an example that sends fontification around
>    the bend (key text on middle line):

>           To fix this, remove the \url{sn9c102.ko} from where it appears in
>           \url{/lib/modules/$(uname -r)}, 
>           and install the appropriate \url{gspca-modules} package.

>    N.B. The mode appears aware of the \url command but not the \path
>    command.  The two commands are provided by the same package and they
>    have similar semantics: the arguments may contain characters that are
>    'special' to {\TeX}, but these characters are treated as if verbatim.

I installed a patch in the trunk which fixes your example.
It does not really handle \url specially but instead changes the
handling of $ to be a bit more conservative.

So \url{foo$bar$baz} will still highlight "$bar$" with the tex-math
face, for example.  But a lone $ should not cause the whole rest of the
document to be mis-fontified any more, or at least much less often.
OTOH it will probably cause some valid $...$ math uses to fail to be
highlighted with the tex-math face.


        Stefan


--- lisp/textmodes/tex-mode.el  2012-07-11 23:13:41 +0000
+++ lisp/textmodes/tex-mode.el  2012-07-17 07:59:18 +0000
@@ -476,25 +476,28 @@
                      '("input" "include" "includeonly" "bibliography"
                        "epsfig" "psfig" "epsf" "nofiles" "usepackage"
                        "documentstyle" "documentclass" "verbatiminput"
-                       "includegraphics" "includegraphics*"
-                       "url" "nolinkurl")
+                       "includegraphics" "includegraphics*")
                      t))
+           (verbish (regexp-opt '("url" "nolinkurl" "path") t))
           ;; Miscellany.
           (slash "\\\\")
           (opt " *\\(\\[[^]]*\\] *\\)*")
           ;; This would allow highlighting \newcommand\CMD but requires
           ;; adapting subgroup numbers below.
           ;; (arg 
"\\(?:{\\(\\(?:[^{}\\]+\\|\\\\.\\|{[^}]*}\\)+\\)\\|\\\\[a-z*]+\\)"))
-          (arg "{\\(\\(?:[^{}\\]+\\|\\\\.\\|{[^}]*}\\)+\\)"))
-      (list
-       ;; display $$ math $$
-       ;; We only mark the match between $$ and $$ because the $$ delimiters
-       ;; themselves have already been marked (along with $..$) by syntactic
-       ;; fontification.  Also this is done at the very beginning so as to
-       ;; interact with the other keywords in the same way as $...$ does.
-       (list "\\$\\$\\([^$]+\\)\\$\\$" 1 'tex-math-face)
+           (inbraces-re (lambda (re)
+                          (concat "\\(?:[^{}\\]\\|\\\\.\\|" re "\\)")))
+          (arg (concat "{\\(" (funcall inbraces-re "{[^}]*}") "+\\)")))
+      `( ;; Highlight $$math$$ and $math$.
+        ;; This is done at the very beginning so as to interact with the other
+        ;; keywords in the same way as comments and strings.
+        (,(concat "\\$\\$?\\(?:[^$\\{}]\\|\\\\.\\|{"
+                  (funcall inbraces-re
+                           (concat "{" (funcall inbraces-re "{[^}]*}") "*}"))
+                  "*}\\)+\\$?\\$")
+         (0 tex-math-face))
        ;; Heading args.
-       (list (concat slash headings "\\*?" opt arg)
+        (,(concat slash headings "\\*?" opt arg)
             ;; If ARG ends up matching too much (if the {} don't match, e.g.)
             ;; jit-lock will do funny things: when updating the buffer
             ;; the re-highlighting is only done locally so it will just
@@ -507,15 +510,17 @@
             ;; Using `keep' works around this un-intuitive behavior as well
             ;; as improves the behavior in the very rare case where you do
             ;; have a comment in ARG.
-            3 'font-lock-function-name-face 'keep)
-       (list (concat slash "\\(?:provide\\|\\(?:re\\)?new\\)command\\** 
*\\(\\\\[A-Za-z@]+\\)")
-            1 'font-lock-function-name-face 'keep)
+         3 font-lock-function-name-face keep)
+        (,(concat slash "\\(?:provide\\|\\(?:re\\)?new\\)command\\** 
*\\(\\\\[A-Za-z@]+\\)")
+         1 font-lock-function-name-face keep)
        ;; Variable args.
-       (list (concat slash variables " *" arg) 2 'font-lock-variable-name-face)
+        (,(concat slash variables " *" arg) 2 font-lock-variable-name-face)
        ;; Include args.
-       (list (concat slash includes opt arg) 3 'font-lock-builtin-face)
+        (,(concat slash includes opt arg) 3 font-lock-builtin-face)
+        ;; Verbatim-like args.
+        (,(concat slash verbish opt arg) 3 'tex-verbatim)
        ;; Definitions.  I think.
-       '("^[ \t]*\\\\def *\\\\\\(\\(\\w\\|@\\)+\\)"
+        ("^[ \t]*\\\\def *\\\\\\(\\(\\w\\|@\\)+\\)"
         1 font-lock-function-name-face))))
   "Subdued expressions to highlight in TeX modes.")
 
@@ -629,7 +634,7 @@
             (1 (tex-font-lock-suscript (match-beginning 0)) append))))
   "Experimental expressions to highlight in TeX modes.")
 
-(defvar tex-font-lock-keywords tex-font-lock-keywords-1
+(defconst tex-font-lock-keywords tex-font-lock-keywords-1
   "Default expressions to highlight in TeX modes.")
 
 (defvar tex-verbatim-environments
@@ -1219,7 +1224,7 @@
   (set (make-local-variable 'font-lock-defaults)
        '((tex-font-lock-keywords tex-font-lock-keywords-1
          tex-font-lock-keywords-2 tex-font-lock-keywords-3)
-        nil nil ((?$ . "\"")) nil
+        nil nil nil nil
         ;; Who ever uses that anyway ???
         (font-lock-mark-block-function . mark-paragraph)
         (font-lock-syntactic-face-function