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[Emacs-diffs] master f1d414b: Allow empty argument to `regexp-opt-charse
From: |
Mattias Engdegård |
Subject: |
[Emacs-diffs] master f1d414b: Allow empty argument to `regexp-opt-charset' |
Date: |
Sat, 29 Jun 2019 05:13:20 -0400 (EDT) |
branch: master
commit f1d414b98f2df3d31abfa710ecbbc0223f73aed1
Author: Mattias Engdegård <address@hidden>
Commit: Mattias Engdegård <address@hidden>
Allow empty argument to `regexp-opt-charset'
* test/lisp/emacs-lisp/regexp-opt-tests.el (regexp-opt-charset):
Handle nil argument, and use regexp-quote for singletons.
* lisp/emacs-lisp/regexp-opt.el (regexp-opt-charset): Expand tests.
---
lisp/emacs-lisp/regexp-opt.el | 20 ++++++++++++--------
test/lisp/emacs-lisp/regexp-opt-tests.el | 29 ++++++++++++++++++++++++-----
2 files changed, 36 insertions(+), 13 deletions(-)
diff --git a/lisp/emacs-lisp/regexp-opt.el b/lisp/emacs-lisp/regexp-opt.el
index 00f72e2..b6104f2 100644
--- a/lisp/emacs-lisp/regexp-opt.el
+++ b/lisp/emacs-lisp/regexp-opt.el
@@ -279,7 +279,9 @@ Merges keywords to avoid backtracking in Emacs's regexp
matcher."
(defun regexp-opt-charset (chars)
"Return a regexp to match a character in CHARS.
-CHARS should be a list of characters."
+CHARS should be a list of characters.
+If CHARS is the empty list, the return value is a regexp that
+never matches anything."
;; The basic idea is to find character ranges. Also we take care in the
;; position of character set meta characters in the character set regexp.
;;
@@ -326,13 +328,15 @@ CHARS should be a list of characters."
(while (>= end start)
(setq charset (format "%s%c" charset start))
(setq start (1+ start)))))
- ;;
- ;; Make sure a caret is not first and a dash is first or last.
- (if (and (string-equal charset "") (string-equal bracket ""))
- (if (string-equal dash "")
- "\\^" ; [^] is not a valid regexp
- (concat "[" dash caret "]"))
- (concat "[" bracket charset caret dash "]"))))
+
+ ;; Make sure that ] is first, ^ is not first, - is first or last.
+ (let ((all (concat bracket charset caret dash)))
+ (pcase (length all)
+ (0 regexp-unmatchable)
+ (1 (regexp-quote all))
+ (_ (if (string-equal all "^-")
+ "[-^]"
+ (concat "[" all "]")))))))
(defun regexp-opt--contains-prefix (strings)
diff --git a/test/lisp/emacs-lisp/regexp-opt-tests.el
b/test/lisp/emacs-lisp/regexp-opt-tests.el
index 1fc4990..927de8c 100644
--- a/test/lisp/emacs-lisp/regexp-opt-tests.el
+++ b/test/lisp/emacs-lisp/regexp-opt-tests.el
@@ -1,4 +1,4 @@
-;;; regexp-tests.el --- Test suite for regular expression handling.
+;;; regexp-opt-tests.el --- Tests for regexp-opt.el
;; Copyright (C) 2013-2019 Free Software Foundation, Inc.
@@ -25,9 +25,28 @@
(require 'regexp-opt)
-(ert-deftest regexp-test-regexp-opt ()
- "Test the `compilation-error-regexp-alist' regexps.
-The test data is in `compile-tests--test-regexps-data'."
- (should (string-match (regexp-opt-charset '(?^)) "a^b")))
+(ert-deftest regexp-opt-charset ()
+ (should (equal (regexp-opt-charset '(?a ?b ?a)) "[ab]"))
+ (should (equal (regexp-opt-charset '(?D ?d ?B ?a ?b ?C ?7 ?a ?c ?A))
+ "[7A-Da-d]"))
+ (should (equal (regexp-opt-charset '(?a)) "a"))
+
+ (should (equal (regexp-opt-charset '(?^)) "\\^"))
+ (should (equal (regexp-opt-charset '(?-)) "-"))
+ (should (equal (regexp-opt-charset '(?\])) "]"))
+ (should (equal (regexp-opt-charset '(?^ ?\])) "[]^]"))
+ (should (equal (regexp-opt-charset '(?^ ?-)) "[-^]"))
+ (should (equal (regexp-opt-charset '(?- ?\])) "[]-]"))
+ (should (equal (regexp-opt-charset '(?- ?\] ?^)) "[]^-]"))
+
+ (should (equal (regexp-opt-charset '(?^ ?a)) "[a^]"))
+ (should (equal (regexp-opt-charset '(?- ?a)) "[a-]"))
+ (should (equal (regexp-opt-charset '(?\] ?a)) "[]a]"))
+ (should (equal (regexp-opt-charset '(?^ ?\] ?a)) "[]a^]"))
+ (should (equal (regexp-opt-charset '(?^ ?- ?a)) "[a^-]"))
+ (should (equal (regexp-opt-charset '(?- ?\] ?a)) "[]a-]"))
+ (should (equal (regexp-opt-charset '(?- ?\] ?^ ?a)) "[]a^-]"))
+
+ (should (equal (regexp-opt-charset '()) regexp-unmatchable)))
;;; regexp-tests.el ends here.
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