procyberian/emacs
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

cl-loop: Calculate the array length just once

Browse source 
* lisp/emacs-lisp/cl-macs.el (cl--parse-loop-clause):
Dont calculate the array length on each iteration (Bug#29866).
This commit is contained in:
Tino Calancha 2018-01-08 00:33:13 +09:00
parent 378be8df8d
commit bfca19e475
1 changed files with 9 additions and 3 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

12
lisp/emacs-lisp/cl-macs.el
View file

@ -1317,11 +1317,13 @@ For more details, see Info node `(cl)Loop Facility'.
((memq word '(across across-ref))
(let ((temp-vec (make-symbol "--cl-vec--"))
(temp-len (make-symbol "--cl-len--"))
(temp-idx (make-symbol "--cl-idx--")))
(push (list temp-vec (pop cl--loop-args)) loop-for-bindings)
(push (list temp-len `(length ,temp-vec)) loop-for-bindings)
(push (list temp-idx -1) loop-for-bindings)
(push `(< (setq ,temp-idx (1+ ,temp-idx))
(length ,temp-vec))
,temp-len)
cl--loop-body)
(if (eq word 'across-ref)
(push (list var `(aref ,temp-vec ,temp-idx))
@ -1336,6 +1338,7 @@ For more details, see Info node `(cl)Loop Facility'.
(error "Expected `of'"))))
(seq (cl--pop2 cl--loop-args))
(temp-seq (make-symbol "--cl-seq--"))
(temp-len (make-symbol "--cl-len--"))
(temp-idx
(if (eq (car cl--loop-args) 'using)
(if (and (= (length (cadr cl--loop-args)) 2)
@ -1346,16 +1349,19 @@ For more details, see Info node `(cl)Loop Facility'.
(push (list temp-seq seq) loop-for-bindings)
(push (list temp-idx 0) loop-for-bindings)
(if ref
(let ((temp-len (make-symbol "--cl-len--")))
(progn
(push (list temp-len `(length ,temp-seq))
loop-for-bindings)
(push (list var `(elt ,temp-seq ,temp-idx))
cl--loop-symbol-macs)
(push `(< ,temp-idx ,temp-len) cl--loop-body))
;; Evaluate seq length just if needed, that is, when seq is not a cons.
(push (list temp-len (or (consp seq) `(length ,temp-seq)))
loop-for-bindings)
(push (list var nil) loop-for-bindings)
(push `(and ,temp-seq
(or (consp ,temp-seq)
(< ,temp-idx (length ,temp-seq))))
(< ,temp-idx ,temp-len)))
cl--loop-body)
(push (list var `(if (consp ,temp-seq)
(pop ,temp-seq)