ivy.el (ivy--regex-fuzzy): Optimize regex "(a).*?(b)" -> "(a)[^b]*(b)"

* ivy-test.el (ivy--regex-fuzzy): Update tests. Thanks to @PythonNut and @dsedivec for the idea. Re #848
abo-abo · Nov 26, 2018 · 7b6765b · 7b6765b
1 parent 79543f3
commit 7b6765b
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Showing 2 changed files with 12 additions and 9 deletions.
diff --git a/ivy-test.el b/ivy-test.el
@@ -249,13 +249,13 @@ will bring the behavior in line with the newer Emacsen."
 
 (ert-deftest ivy--regex-fuzzy ()
   (should (string= (ivy--regex-fuzzy "tmux")
-                   "\\(t\\).*?\\(m\\).*?\\(u\\).*?\\(x\\)"))
+                   "\\(t\\)[^m]*\\(m\\)[^u]*\\(u\\)[^x]*\\(x\\)"))
   (should (string= (ivy--regex-fuzzy ".tmux")
-                   "\\(\\.\\).*?\\(t\\).*?\\(m\\).*?\\(u\\).*?\\(x\\)"))
+                   "\\(\\.\\)[^t]*\\(t\\)[^m]*\\(m\\)[^u]*\\(u\\)[^x]*\\(x\\)"))
   (should (string= (ivy--regex-fuzzy "^tmux")
-                   "^\\(t\\).*?\\(m\\).*?\\(u\\).*?\\(x\\)"))
+                   "^\\(t\\)[^m]*\\(m\\)[^u]*\\(u\\)[^x]*\\(x\\)"))
   (should (string= (ivy--regex-fuzzy "^tmux$")
-                   "^\\(t\\).*?\\(m\\).*?\\(u\\).*?\\(x\\)$"))
+                   "^\\(t\\)[^m]*\\(m\\)[^u]*\\(u\\)[^x]*\\(x\\)$"))
   (should (string= (ivy--regex-fuzzy "")
                    ""))
   (should (string= (ivy--regex-fuzzy "^")

diff --git a/ivy.el b/ivy.el
@@ -2516,11 +2516,14 @@ Insert .* between each char."
   (if (string-match "\\`\\(\\^?\\)\\(.*?\\)\\(\\$?\\)\\'" str)
       (prog1
           (concat (match-string 1 str)
-                  (mapconcat
-                   (lambda (x)
-                     (format "\\(%s\\)" (regexp-quote (string x))))
-                   (string-to-list (match-string 2 str))
-                   ".*?")
+                  (let ((lst (string-to-list (match-string 2 str))))
+                    (apply #'concat
+                           (cl-mapcar
+                            #'concat
+                            (cons "" (cdr (mapcar (lambda (c) (format "[^%c]*" c))
+                                                  lst)))
+                            (mapcar (lambda (x) (format "\\(%s\\)" (regexp-quote (char-to-string x))))
+                                    lst))))
                   (match-string 3 str))
         (setq ivy--subexps (length (match-string 2 str))))
     str))