tildify.el: Optimise environments regexes

* lisp/textmodes/tildify.el (tildify-ignored-environments-alist):
Each time beginning of an environment to ignore is found,
`tildify-find-env' needs to identify regexp for the ending
of the environment.  This is done by trying all the opening
regexes on matched text in a loop, so to speed that up, this
loop should have fewer things to match, which can be done by
using alternatives in the opening regexes.

Coincidentally, this should make matching of the opening
regexp faster as well thanks to the use of `regexp-opt' and
having common prefix pulled from many regexes.

1 files changed, 15 insertions, 22 deletions

diff --git a/lisp/textmodes/tildify.el b/lisp/textmodes/tildify.el
index 6dd471d49ad..39ccad717d4 100644
--- a/lisp/textmodes/tildify.el
+++ b/lisp/textmodes/tildify.el
@@ -119,42 +119,35 @@ mode, the item for the mode SYMBOL is looked up in the alist instead."
                                (symbol :tag "Like other")))))
 
 (defcustom tildify-ignored-environments-alist
-  '((latex-mode
+  `((latex-mode
      ("\\\\\\\\" . "")		; do not remove this
-     ("\\\\begin{verbatim}" . "\\\\end{verbatim}")
+     (,(eval-when-compile (concat
+                           "\\\\begin{\\("
+                           (regexp-opt '("verbatim" "math" "displaymath"
+                                         "equation" "eqnarray" "eqnarray*"))
+                           "\\)}"))
+      . ("\\\\end{" 1 "}"))
      ("\\\\verb\\*?\\(.\\)" . (1))
-     ("\\$\\$" . "\\$\\$")
-     ("\\$" . "\\$")
+     ("\\$\\$?" . (0))
      ("\\\\(" . "\\\\)")
      ("\\\\[[]" . "\\\\[]]")
-     ("\\\\begin{math}" . "\\\\end{math}")
-     ("\\\\begin{displaymath}" . "\\\\end{displaymath}")
-     ("\\\\begin{equation}" . "\\\\end{equation}")
-     ("\\\\begin{eqnarray\\*?}" . "\\\\end{eqnarray\\*?}")
      ("\\\\[a-zA-Z]+\\( +\\|{}\\)[a-zA-Z]*" . "")
      ("%" . "$"))
     (plain-tex-mode . latex-mode)
     (html-mode
-     ("<pre[^>]*>" . "</pre>")
-     ("<dfn>" . "</dfn>")
-     ("<code>" . "</code>")
-     ("<samp>" . "</samp>")
-     ("<kbd>" . "</kbd>")
-     ("<var>" . "</var>")
-     ("<PRE[^>]*>" . "</PRE>")
-     ("<DFN>" . "</DFN>")
-     ("<CODE>" . "</CODE>")
-     ("<SAMP>" . "</SAMP>")
-     ("<KBD>" . "</KBD>")
-     ("<VAR>" . "</VAR>")
+     (,(eval-when-compile (concat
+                           "<\\("
+                           (regexp-opt '("pre" "dfn" "code" "samp" "kbd" "var"
+                                         "PRE" "DFN" "CODE" "SAMP" "KBD" "VAR"))
+                           "\\)\\>[^>]*>"))
+      . ("</" 1 ">"))
      ("<! *--" . "-- *>")
      ("<" . ">"))
     (sgml-mode . html-mode)
     (xml-mode
      ("<! *--" . "-- *>")
      ("<" . ">"))
-    (nxml-mode . xml-mode)
-    (t nil))
+    (nxml-mode . xml-mode))
   "Alist specifying ignored structured text environments.
 Parts of text defined in this alist are skipped without performing hard space
 insertion on them.  These setting allow skipping text parts like verbatim or