Remove the optional KEEP-ORDER argument to regexp-opt

This argument was added for the 'or' clause in rx, but it turned out
to be a bad idea (bug#37659), and there seems to be little other use
for it.

* lisp/emacs-lisp/regexp-opt.el (regexp-opt): Remove KEEP-ORDER.
* doc/lispref/searching.texi (Regexp Functions):
* etc/NEWS: Remove it from the documentation.
* test/lisp/emacs-lisp/regexp-opt-tests.el (regexp-opt-test--match-all)
(regexp-opt-test--check-perm, regexp-opt-test--explain-perm)
(regexp-opt-keep-order, regexp-opt-longest-match): Simplify test.

1 files changed, 7 insertions, 37 deletions

diff --git a/test/lisp/emacs-lisp/regexp-opt-tests.el b/test/lisp/emacs-lisp/regexp-opt-tests.el
index 9b4567c72cc..0179ac4f1f4 100644
--- a/test/lisp/emacs-lisp/regexp-opt-tests.el
+++ b/test/lisp/emacs-lisp/regexp-opt-tests.el
@@ -47,43 +47,13 @@
   (mapcar (lambda (i) (regexp-opt-test--permutation i list))
           (number-sequence 0 (1- (regexp-opt-test--factorial (length list))))))
 
-(defun regexp-opt-test--match-all (words re)
-  (mapcar (lambda (w) (and (string-match re w)
-                           (match-string 0 w)))
-          words))
-
-(defun regexp-opt-test--check-perm (perm)
-  (let* ((ref-re (mapconcat #'regexp-quote perm "\\|"))
-         (opt-re (regexp-opt perm nil t))
-         (ref (regexp-opt-test--match-all perm ref-re))
-         (opt (regexp-opt-test--match-all perm opt-re)))
-    (equal opt ref)))
-
-(defun regexp-opt-test--explain-perm (perm)
-  (let* ((ref-re (mapconcat #'regexp-quote perm "\\|"))
-         (opt-re (regexp-opt perm nil t))
-         (ref (regexp-opt-test--match-all perm ref-re))
-         (opt (regexp-opt-test--match-all perm opt-re)))
-    (concat "\n"
-            (format "Naïve regexp:     %s\n" ref-re)
-            (format "Optimized regexp: %s\n" opt-re)
-            (format "Got:      %s\n" opt)
-            (format "Expected: %s\n" ref))))
-
-(put 'regexp-opt-test--check-perm 'ert-explainer 'regexp-opt-test--explain-perm)
-
-(ert-deftest regexp-opt-keep-order ()
-  "Check that KEEP-ORDER works."
-  (dolist (perm (regexp-opt-test--permutations '("abc" "bca" "cab")))
-    (should (regexp-opt-test--check-perm perm)))
-  (dolist (perm (regexp-opt-test--permutations '("abc" "ab" "bca" "bc")))
-    (should (regexp-opt-test--check-perm perm)))
-  (dolist (perm (regexp-opt-test--permutations '("abxy" "cdxy")))
-    (should (regexp-opt-test--check-perm perm)))
-  (dolist (perm (regexp-opt-test--permutations '("afgx" "bfgx" "afgy" "bfgy")))
-    (should (regexp-opt-test--check-perm perm)))
-  (dolist (perm (regexp-opt-test--permutations '("a" "ab" "ac" "abc")))
-    (should (regexp-opt-test--check-perm perm))))
+(ert-deftest regexp-opt-longest-match ()
+  "Check that the regexp always matches as much as possible."
+  (let ((s "abcd"))
+    (dolist (perm (regexp-opt-test--permutations '("a" "ab" "ac" "abc")))
+      (should (equal (and (string-match (regexp-opt perm) s)
+                          (match-string 0 s))
+                     "abc")))))
 
 (ert-deftest regexp-opt-charset ()
   (should (equal (regexp-opt-charset '(?a ?b ?a)) "[ab]"))