[elpa] externals/auctex 2f1369f 2/5: Fix false negative of texmathp (bug#41559)

[Tassilo Horn]

branch: externals/auctex
commit 2f1369fc0115addb375df0064460178705ff658c
Author: Ikumi Keita <ikumi@ikumi.que.jp>
Commit: Ikumi Keita <ikumi@ikumi.que.jp>

    Fix false negative of texmathp (bug#41559)
    
    * texmathp.el (texmathp-compile): Fix `texmathp-onoff-regexp' to allow
    switch to begin at (point-min).
    Use `regexp-opt' instead of `mapconcat'+`regexp-quote'.
    (texmathp): Use `>=' instead of `>' so that match is updated even when
    arg-on or sw-on begins at (point-min).
    * tests/latex/texmathp-test.el: New test.
---
 tests/latex/texmathp-test.el | 51 ++++++++++++++++++++++++++++++++++++++++++++
 texmathp.el                  | 17 ++++++++-------
 2 files changed, 60 insertions(+), 8 deletions(-)

diff --git a/tests/latex/texmathp-test.el b/tests/latex/texmathp-test.el
new file mode 100644
index 0000000..a1313b9
--- /dev/null
+++ b/tests/latex/texmathp-test.el
@@ -0,0 +1,51 @@
+;;; texmathp-test.el --- tests for texmathp
+
+;; Copyright (C) 2020 Free Software Foundation, Inc.
+
+;; This file is part of AUCTeX.
+
+;; AUCTeX 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 3, or (at your option)
+;; any later version.
+
+;; AUCTeX 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 AUCTeX; see the file COPYING.  If not, write to the Free
+;; Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+;; 02110-1301, USA.
+
+;;; Code:
+
+(require 'ert)
+(require 'latex)
+(require 'texmathp)
+
+;; bug#41559
+(ert-deftest texmathp-bob ()
+  "Test math expressions beginning at BOB are identified correctly."
+  (should (with-temp-buffer
+           (insert "\\(")
+           (LaTeX-mode)
+           (texmathp)))
+
+  (should (with-temp-buffer
+           (insert "\\[")
+           (LaTeX-mode)
+           (texmathp)))
+
+  (should (with-temp-buffer
+           (insert "\\ensuremath{")
+           (LaTeX-mode)
+           (texmathp)))
+
+  (should (with-temp-buffer
+           (insert "$")
+           (LaTeX-mode)
+           (texmathp))))
+
+;;; texmathp-test.el ends here
diff --git a/texmathp.el b/texmathp.el
index ba5aba3..723623b 100644
--- a/texmathp.el
+++ b/texmathp.el
@@ -185,13 +185,11 @@ customize (customize calls it when setting the variable)."
                      ((memq type '(sw-toggle))      'togglers)))
       (set var (cons (car entry) (symbol-value var))))
     (setq texmathp-onoff-regexp
-         (concat "[^\\\\]\\("
-                 (mapconcat 'regexp-quote switches "\\|")
-                 "\\)")
+         (concat "\\(?:[^\\\\]\\|\\`\\)"
+                 (regexp-opt switches t))
          texmathp-toggle-regexp
-         (concat "\\([^\\\\\\$]\\|\\`\\)\\("
-                 (mapconcat 'regexp-quote togglers "\\|")
-                 "\\)"))))
+         (concat "\\([^\\\\\\$]\\|\\`\\)"
+                 (regexp-opt togglers t)))))
 
 (defcustom texmathp-tex-commands nil
   "List of environments and macros influencing (La)TeX math mode.
@@ -287,14 +285,17 @@ See the variable `texmathp-tex-commands' about which 
commands are checked."
 
     ;; Select the nearer match
     (and env-match (setq match env-match))
-    (and mac-match (> (cdr mac-match) (cdr match)) (setq match mac-match))
+    ;; Use `>=' instead of `>' in case called inside \ensuremath{..}
+    ;; beginning just at (point-min).
+    (and mac-match (>= (cdr mac-match) (cdr match)) (setq match mac-match))
     (setq math-on (memq (nth 1 (assoc (car match) texmathp-tex-commands1))
                        '(env-on arg-on)))
 
     ;; Check for switches
     (and (not math-on)
         (setq sw-match (texmathp-match-switch bound))
-        (> (cdr sw-match) (cdr match))
+        ;; Use `>=' instead of `>' by similar reason as above. (bug#41559)
+        (>= (cdr sw-match) (cdr match))
         (eq (nth 1 (assoc (car sw-match) texmathp-tex-commands1)) 'sw-on)
         (setq match sw-match math-on t))