(dolist, dotimes): Use interned symbols for iteration.

(--dotimes-limit--, --dolist-tail--): New defvars.
(looking-back): Doc fix.

diff --git a/lisp/subr.el b/lisp/subr.el
index a94096b184ed23c0ee3efa97c38482b93d64dd57..6a4349e5725493c43460a8e7e28d81b60425e5bc 100644 (file)
--- a/lisp/subr.el
+++ b/lisp/subr.el
@@ -108,6 +108,9 @@ change the list."
   (declare (indent 1) (debug t))
   (cons 'if (cons cond (cons nil body))))
 
+(defvar --dolist-tail-- nil
+  "Temporary variable used in `dolist' expansion.")
+
 (defmacro dolist (spec &rest body)
   "Loop over a list.
 Evaluate BODY with VAR bound to each car from LIST, in turn.
@@ -115,16 +118,22 @@ Then evaluate RESULT to get return value, default nil.
 
 \(fn (VAR LIST [RESULT]) BODY...)"
   (declare (indent 1) (debug ((symbolp form &optional form) body)))
-  (let ((temp (make-symbol "--dolist-temp--")))
+  ;; It would be cleaner to create an uninterned symbol,
+  ;; but that uses a lot more space when many functions in many files
+  ;; use dolist.
+  (let ((temp '--dolist-tail--))
     `(let ((,temp ,(nth 1 spec))
           ,(car spec))
        (while ,temp
         (setq ,(car spec) (car ,temp))
-        (setq ,temp (cdr ,temp))
-        ,@body)
+        ,@body
+        (setq ,temp (cdr ,temp)))
        ,@(if (cdr (cdr spec))
             `((setq ,(car spec) nil) ,@(cdr (cdr spec)))))))
 
+(defvar --dotimes-limit-- nil
+  "Temporary variable used in `dotimes' expansion.")
+
 (defmacro dotimes (spec &rest body)
   "Loop a certain number of times.
 Evaluate BODY with VAR bound to successive integers running from 0,
@@ -133,7 +142,10 @@ the return value (nil if RESULT is omitted).
 
 \(fn (VAR COUNT [RESULT]) BODY...)"
   (declare (indent 1) (debug dolist))
-  (let ((temp (make-symbol "--dotimes-temp--"))
+  ;; It would be cleaner to create an uninterned symbol,
+  ;; but that uses a lot more space when many functions in many files
+  ;; use dotimes.
+  (let ((temp '--dotimes-limit--)
        (start 0)
        (end (nth 1 spec)))
     `(let ((,temp ,end)
@@ -2531,8 +2543,9 @@ STRING should be given if the last search was by `string-match' on STRING."
 (defun looking-back (regexp &optional limit greedy)
   "Return non-nil if text before point matches regular expression REGEXP.
 Like `looking-at' except matches before point, and is slower.
-LIMIT if non-nil speeds up the search by specifying how far back the
-match can start.
+LIMIT if non-nil speeds up the search by specifying a minimum
+starting position, to avoid checking matches that would start
+before LIMIT.
 
 If GREEDY is non-nil, extend the match backwards as far as possible,
 stopping when a single additional previous character cannot be part