Allow string-slice to take zero-length matches

* lisp/emacs-lisp/subr-x.el (string-slice): Allow zero-length
matches.  Code adapted from s.el by Magnar Sveen.

1 files changed, 10 insertions, 13 deletions

diff --git a/lisp/emacs-lisp/subr-x.el b/lisp/emacs-lisp/subr-x.el
index 09c4649817a..8a9424cbb3d 100644
--- a/lisp/emacs-lisp/subr-x.el
+++ b/lisp/emacs-lisp/subr-x.el
@@ -308,19 +308,16 @@ If OMIT-NULLS, empty lines will be removed from the results."
 
 (defun string-slice (string regexp)
   "Split STRING at REGEXP boundaries and return a list of slices.
-The boundaries that match REGEXP are included in the result."
-  (let ((start-substring 0)
-        (start-search 0)
-        (result nil))
-    (save-match-data
-      (while (string-match regexp string start-search)
-        (if (zerop (match-beginning 0))
-            (setq start-search (match-end 0))
-          (push (substring string start-substring (match-beginning 0)) result)
-          (setq start-substring (match-beginning 0)
-                start-search (match-end 0))))
-      (push (substring string start-substring) result)
-      (nreverse result))))
+The boundaries that match REGEXP are included in the result.
+
+Also see `split-string'."
+  (if (zerop (length string))
+      (list "")
+    (let ((i (string-match-p regexp string 1)))
+      (if i
+          (cons (substring string 0 i)
+                (string-slice (substring string i) regexp))
+        (list string)))))
 
 (defun string-pad (string length &optional padding start)
   "Pad STRING to LENGTH using PADDING.