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author | Stefan Monnier <monnier@iro.umontreal.ca> | 2022-04-11 15:10:51 -0400 |
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committer | Stefan Monnier <monnier@iro.umontreal.ca> | 2022-04-11 15:10:51 -0400 |
commit | 6a480c830bc8d313ca3052570487a65411c937c2 (patch) | |
tree | 37fb9665e32576097d3c28ddea81af877924e9ee | |
parent | d6338f8a6a5670d7d7075aa277896d9f74723c7a (diff) | |
download | emacs-6a480c830bc8d313ca3052570487a65411c937c2.tar.gz |
* lisp/emacs-lisp/macroexp.el (macroexp-let2*): Allow common shorthand
-rw-r--r-- | doc/lispref/variables.texi | 10 | ||||
-rw-r--r-- | etc/NEWS | 3 | ||||
-rw-r--r-- | lisp/emacs-lisp/macroexp.el | 14 |
3 files changed, 19 insertions, 8 deletions
diff --git a/doc/lispref/variables.texi b/doc/lispref/variables.texi index f85ed847c47..f0e3f337a69 100644 --- a/doc/lispref/variables.texi +++ b/doc/lispref/variables.texi @@ -2789,13 +2789,13 @@ implemented this way: (gv-define-expander substring (lambda (do place from &optional to) (gv-letplace (getter setter) place - (macroexp-let2* nil ((start from) (end to)) - (funcall do `(substring ,getter ,start ,end) + (macroexp-let2* (from to) + (funcall do `(substring ,getter ,from ,to) (lambda (v) - (macroexp-let2 nil v v + (macroexp-let2* (v) `(progn ,(funcall setter `(cl--set-substring - ,getter ,start ,end ,v)) + ,getter ,from ,to ,v)) ,v)))))))) @end example @end defmac @@ -2808,7 +2808,7 @@ of Common Lisp could be implemented this way: @example (defmacro incf (place &optional n) (gv-letplace (getter setter) place - (macroexp-let2 nil v (or n 1) + (macroexp-let2* ((v (or n 1))) (funcall setter `(+ ,v ,getter))))) @end example @@ -1361,6 +1361,9 @@ functions. * Lisp Changes in Emacs 29.1 +++ +** 'macroexp-let2*' can omit 'test' arg and use single-var bindings. + ++++ ** New variable 'last-event-device' and new function 'device-class'. On X Windows, 'last-event-device' specifies the input extension device from which the last input event originated, and 'device-class' can be diff --git a/lisp/emacs-lisp/macroexp.el b/lisp/emacs-lisp/macroexp.el index e91b302af10..e4bc2df2803 100644 --- a/lisp/emacs-lisp/macroexp.el +++ b/lisp/emacs-lisp/macroexp.el @@ -567,12 +567,20 @@ cases where EXP is a constant." (defmacro macroexp-let2* (test bindings &rest body) "Multiple binding version of `macroexp-let2'. -BINDINGS is a list of elements of the form (SYM EXP). Each EXP -can refer to symbols specified earlier in the binding list." +BINDINGS is a list of elements of the form (SYM EXP) or just SYM, +which then stands for (SYM SYM). +Each EXP can refer to symbols specified earlier in the binding list. + +TEST has to be a symbol, and if it is nil it can be omitted." (declare (indent 2) (debug (sexp (&rest (sexp form)) body))) + (when (consp test) ;; `test' was omitted. + (push bindings body) + (setq bindings test) + (setq test nil)) (pcase-exhaustive bindings ('nil (macroexp-progn body)) - (`((,var ,exp) . ,tl) + (`(,(or `(,var ,exp) (and (pred symbolp) var (let exp var))) + . ,tl) `(macroexp-let2 ,test ,var ,exp (macroexp-let2* ,test ,tl ,@body))))) |