diff options
Diffstat (limited to 'lisp/emacs-lisp/lisp-mode.el')
| -rw-r--r-- | lisp/emacs-lisp/lisp-mode.el | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/lisp/emacs-lisp/lisp-mode.el b/lisp/emacs-lisp/lisp-mode.el index 4576f5cd6ba..f8b935eb90b 100644 --- a/lisp/emacs-lisp/lisp-mode.el +++ b/lisp/emacs-lisp/lisp-mode.el @@ -235,6 +235,19 @@ (match-beginning 0))))) (throw 'found t)))))) +(defmacro let-when-compile (bindings &rest body) + "Like `let', but allow for compile time optimization. +Use BINDINGS as in regular `let', but in BODY each usage should +be wrapped in `eval-when-compile'. +This will generate compile-time constants from BINDINGS." + (declare (indent 1) (debug let)) + (cl-progv (mapcar #'car bindings) + (mapcar (lambda (x) (eval (cadr x))) bindings) + (macroexpand-all + (macroexp-progn + body) + macroexpand-all-environment))) + (let-when-compile ((lisp-fdefs '("defmacro" "defun")) (lisp-vdefs '("defvar")) |