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| author | Mattias Engdegård <mattiase@acm.org> | 2021-06-03 21:15:11 +0200 |
|---|---|---|
| committer | Mattias Engdegård <mattiase@acm.org> | 2021-06-03 21:28:10 +0200 |
| commit | a517b77ffe8ed8cdfeec1a9b5258fd16b2446214 (patch) | |
| tree | d0d336d70618a55792bd92998f9ea2b0ad8578ad /lisp/emacs-lisp | |
| parent | c3b44858dc9d9eeda4863ed6ffafbeb446374465 (diff) | |
| download | emacs-a517b77ffe8ed8cdfeec1a9b5258fd16b2446214.tar.gz emacs-a517b77ffe8ed8cdfeec1a9b5258fd16b2446214.tar.bz2 emacs-a517b77ffe8ed8cdfeec1a9b5258fd16b2446214.zip | |
Optimise (cons X nil) to (list X)
* lisp/emacs-lisp/byte-opt.el (byte-optimize-cons): New function.
Diffstat (limited to 'lisp/emacs-lisp')
| -rw-r--r-- | lisp/emacs-lisp/byte-opt.el | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/lisp/emacs-lisp/byte-opt.el b/lisp/emacs-lisp/byte-opt.el index 10a50da4628..99e84e23ad8 100644 --- a/lisp/emacs-lisp/byte-opt.el +++ b/lisp/emacs-lisp/byte-opt.el @@ -1269,6 +1269,14 @@ See Info node `(elisp) Integer Basics'." form) form)) +(put 'cons 'byte-optimizer #'byte-optimize-cons) +(defun byte-optimize-cons (form) + ;; (cons X nil) => (list X) + (if (and (= (safe-length form) 3) + (null (nth 2 form))) + `(list ,(nth 1 form)) + form)) + ;; Fixme: delete-char -> delete-region (byte-coded) ;; optimize string-as-unibyte, string-as-multibyte, string-make-unibyte, ;; string-make-multibyte for constant args. |