Re: Scan of regexps in Emacs (March 17)

[Paul Eggert <eggert@cs.ucla.edu>]

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Thanks for proofreading that. I installed the attached to try to fix the 
problems you noted.

I also fixed a couple of other problems if I happened to run across them. First, 
the regexp [a-b-c] is ambiguous according to POSIX, and should be avoided. 
Second, a regexp like [[:alnum:]-z] is also ambiguous for the same reason. 
Perhaps these regexps currently have a particular behavior in Emacs but it's not 
documented as far as I know and code should avoid them. Perhaps the trawler 
could be modified to catch them.

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From e14c0d748efe35afc653151ff18c4dd93dcc456e Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Tue, 19 Mar 2019 18:45:17 -0700
Subject: [PATCH] More minor regex cleanup
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Problems reported by Mattias Engdegård in:
https://lists.gnu.org/r/emacs-devel/2019-03/msg00643.html
plus a few others that I noticed.
* lisp/auth-source-pass.el (auth-source-pass--parse-data):
* lisp/org/org-datetree.el (org-datetree--find-create):
* lisp/org/org-pcomplete.el (org-thing-at-point):
* lisp/progmodes/js.el (js--end-of-do-while-loop-p):
* lisp/textmodes/sgml-mode.el:
(sgml-electric-tag-pair-before-change-function):
* lisp/textmodes/texnfo-upd.el (texinfo-menu-copy-old-description):
* lisp/url/url-http.el (url-http-parse-response):
Fix regular expression and similar syntax.
---
 lisp/auth-source-pass.el     | 2 +-
 lisp/org/org-datetree.el     | 9 +++++----
 lisp/org/org-pcomplete.el    | 4 ++--
 lisp/progmodes/cperl-mode.el | 2 +-
 lisp/progmodes/js.el         | 2 +-
 lisp/textmodes/sgml-mode.el  | 7 ++++---
 lisp/textmodes/texnfo-upd.el | 2 +-
 lisp/url/url-http.el         | 2 +-
 8 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/lisp/auth-source-pass.el b/lisp/auth-source-pass.el
index 29ff9c6685..4283ed0392 100644
--- a/lisp/auth-source-pass.el
+++ b/lisp/auth-source-pass.el
@@ -139,7 +139,7 @@ auth-source-pass--parse-secret
 (defun auth-source-pass--parse-data (contents)
   "Parse the password-store data in the string CONTENTS and return an alist.
 CONTENTS is the contents of a password-store formatted file."
-  (let ((lines (split-string contents "\n" t "\\\s")))
+  (let ((lines (split-string contents "\n" t "[ \t]+")))
     (seq-remove #'null
                 (mapcar (lambda (line)
                           (let ((pair (mapcar (lambda (s) (string-trim s))
diff --git a/lisp/org/org-datetree.el b/lisp/org/org-datetree.el
index aea2c8d3d6..b4797de1e5 100644
--- a/lisp/org/org-datetree.el
+++ b/lisp/org/org-datetree.el
@@ -138,15 +138,16 @@ org-datetree-find-iso-week-create
        "^\\*+[ \t]+%d-%02d-\\([0123][0-9]\\) \\w+$"
        year month day))))
 
-(defun org-datetree--find-create (regex year &optional month day insert)
-  "Find the datetree matched by REGEX for YEAR, MONTH, or DAY.
-REGEX is passed to `format' with YEAR, MONTH, and DAY as
+(defun org-datetree--find-create
+    (regex-template year &optional month day insert)
+  "Find the datetree matched by REGEX-TEMPLATE for YEAR, MONTH, or DAY.
+REGEX-TEMPLATE is passed to `format' with YEAR, MONTH, and DAY as
 arguments.  Match group 1 is compared against the specified date
 component.  If INSERT is non-nil and there is no match then it is
 inserted into the buffer."
   (when (or month day)
     (org-narrow-to-subtree))
-  (let ((re (format regex year month day))
+  (let ((re (format regex-template year month day))
 	match)
     (goto-char (point-min))
     (while (and (setq match (re-search-forward re nil t))
diff --git a/lisp/org/org-pcomplete.el b/lisp/org/org-pcomplete.el
index 49983c40a5..cf272de90a 100644
--- a/lisp/org/org-pcomplete.el
+++ b/lisp/org/org-pcomplete.el
@@ -49,10 +49,10 @@ org-thing-at-point
   "Examine the thing at point and let the caller know what it is.
 The return value is a string naming the thing at point."
   (let ((beg1 (save-excursion
-		(skip-chars-backward "[:alnum:]-_@")
+		(skip-chars-backward "-[:alnum:]_@")
 		(point)))
 	(beg (save-excursion
-	       (skip-chars-backward "a-zA-Z0-9-_:$")
+	       (skip-chars-backward "-a-zA-Z0-9_:$")
 	       (point)))
 	(line-to-here (buffer-substring (point-at-bol) (point))))
     (cond
diff --git a/lisp/progmodes/cperl-mode.el b/lisp/progmodes/cperl-mode.el
index 0b6008a511..73b55e29a5 100644
--- a/lisp/progmodes/cperl-mode.el
+++ b/lisp/progmodes/cperl-mode.el
@@ -1884,7 +1884,7 @@ cperl-comment-indent
 ;;Point is at start of real comment."
 ;;  (let ((c (current-column)) target cnt prevc)
 ;;    (if (= c comment-column) nil
-;;      (setq cnt (skip-chars-backward "[ \t]"))
+;;      (setq cnt (skip-chars-backward " \t"))
 ;;      (setq target (max (1+ (setq prevc
 ;;			     (current-column))) ; Else indent at comment column
 ;;		   comment-column))
diff --git a/lisp/progmodes/js.el b/lisp/progmodes/js.el
index f1ec5ceea5..4d91da7334 100644
--- a/lisp/progmodes/js.el
+++ b/lisp/progmodes/js.el
@@ -1908,7 +1908,7 @@ js--end-of-do-while-loop-p
     (save-match-data
       (when (looking-at "\\s-*\\_<while\\_>")
 	(if (save-excursion
-	      (skip-chars-backward "[ \t\n]*}")
+	      (skip-chars-backward " \t\n}")
 	      (looking-at "[ \t\n]*}"))
 	    (save-excursion
 	      (backward-list) (forward-symbol -1) (looking-at "\\_<do\\_>"))
diff --git a/lisp/textmodes/sgml-mode.el b/lisp/textmodes/sgml-mode.el
index e49144e290..9e3be99af1 100644
--- a/lisp/textmodes/sgml-mode.el
+++ b/lisp/textmodes/sgml-mode.el
@@ -894,7 +894,7 @@ sgml-electric-tag-pair-before-change-function
   (condition-case err
   (save-excursion
     (goto-char end)
-    (skip-chars-backward "[:alnum:]-_.:")
+    (skip-chars-backward "-[:alnum:]_.:")
     (if (and ;; (<= (point) beg) ; This poses problems for downcase-word.
              (or (eq (char-before) ?<)
                  (and (eq (char-before) ?/)
@@ -902,7 +902,7 @@ sgml-electric-tag-pair-before-change-function
              (null (get-char-property (point) 'text-clones)))
         (let* ((endp (eq (char-before) ?/))
                (cl-start (point))
-               (cl-end (progn (skip-chars-forward "[:alnum:]-_.:") (point)))
+	       (cl-end (progn (skip-chars-forward "-[:alnum:]_.:") (point)))
                (match
                 (if endp
                     (when (sgml-skip-tag-backward 1) (forward-char 1) t)
@@ -919,7 +919,8 @@ sgml-electric-tag-pair-before-change-function
                      (equal (buffer-substring cl-start cl-end)
                             (buffer-substring (point)
                                               (save-excursion
-                                                (skip-chars-forward "[:alnum:]-_.:")
+						(skip-chars-forward
+						 "-[:alnum:]_.:")
                                                 (point))))
                      (or (not endp) (eq (char-after cl-end) ?>)))
             (when clones
diff --git a/lisp/textmodes/texnfo-upd.el b/lisp/textmodes/texnfo-upd.el
index 8c6e23eae4..e960e992a8 100644
--- a/lisp/textmodes/texnfo-upd.el
+++ b/lisp/textmodes/texnfo-upd.el
@@ -642,7 +642,7 @@ texinfo-menu-copy-old-description
   "Return description field of old menu line as string.
 Point must be located just after the node name.  Point left before description.
 Single argument, END-OF-MENU, is position limiting search."
-  (skip-chars-forward "[:.,\t\n ]+")
+  (skip-chars-forward ":.,\t\n ")
   ;; don't copy a carriage return at line beginning with asterisk!
   ;; don't copy @detailmenu or @end menu or @ignore as descriptions!
   ;; do copy a description that begins with an `@'!
diff --git a/lisp/url/url-http.el b/lisp/url/url-http.el
index 46baa8a148..1fbc087073 100644
--- a/lisp/url/url-http.el
+++ b/lisp/url/url-http.el
@@ -517,7 +517,7 @@ url-http-parse-response
   (setq url-http-response-version
 	(buffer-substring (point)
 			  (progn
-			    (skip-chars-forward "[0-9].")
+			    (skip-chars-forward "0-9.")
 			    (point))))
   (setq url-http-response-status (read (current-buffer))))
 
-- 
2.17.1