From 13411853b25f3c861d9364961f8ca0b18a9b5ed4 Mon Sep 17 00:00:00 2001 From: Stefan Monnier Date: Mon, 30 May 2016 16:35:00 -0400 Subject: [PATCH] * lisp/emacs-lisp/pcase.el: Undo last change's spurious changes --- lisp/emacs-lisp/pcase.el | 50 ++++------------------------------------ 1 file changed, 4 insertions(+), 46 deletions(-) diff --git a/lisp/emacs-lisp/pcase.el b/lisp/emacs-lisp/pcase.el index b18472d7e3d..0b8dddfacc9 100644 --- a/lisp/emacs-lisp/pcase.el +++ b/lisp/emacs-lisp/pcase.el @@ -105,8 +105,6 @@ specs))))) (edebug-match cursor (cons '&or specs)))) -(fset 'pcase--canon #'identity) - ;;;###autoload (defmacro pcase (exp &rest cases) "Evaluate EXP and attempt to match it against structural patterns. @@ -334,8 +332,7 @@ any kind of error." ;; to a separate function if that number is too high. ;; ;; We've already used this branch. So it is shared. - (let* (;; (code (car prev)) - (cdrprev (cdr prev)) + (let* ((code (car prev)) (cdrprev (cdr prev)) (prevvars (car cdrprev)) (cddrprev (cdr cdrprev)) (res (car cddrprev))) (unless (symbolp res) @@ -437,10 +434,8 @@ to this macro." ;; Don't use let*, otherwise macroexp-let* may merge it with some surrounding ;; let* which might prevent the setcar/setcdr in pcase--expand's fancy ;; codegen from later metamorphosing this let into a funcall. - (if vars - `(let ,(mapcar (lambda (b) (list (car b) (cdr b))) vars) - ,@code) - `(progn ,@code))) + `(let ,(mapcar (lambda (b) (list (car b) (cdr b))) vars) + ,@code)) (defun pcase--small-branch-p (code) (and (= 1 (length code)) @@ -456,36 +451,7 @@ to this macro." (cond ((eq else :pcase--dontcare) then) ((eq then :pcase--dontcare) (debug) else) ;Can/should this ever happen? - ;; FIXME: The code below shows that there are some opportunities for sharing, - ;; but it's rarely useful to do it here, since almost all sharing found - ;; shares a trivial expression. - ;; But among the common trivial expressions are those of the form - ;; (funcall pcase-0). For this case, there could be a significant payoff - ;; if we could find the sharing-opportunity earlier so as to avoid - ;; the creation of pcase-0. - ;; ((and (eq 'if (car-safe then)) - ;; (equal (macroexp-unprogn (macroexp-progn (nthcdr 3 then))) - ;; (macroexp-unprogn else))) - ;; (let ((res (macroexp-if `(and ,test ,(nth 1 then)) - ;; (nth 2 then) else))) - ;; (message "if+if => if-and: sharing %S" else) - ;; res)) - ;; ((and (eq 'if (car-safe else)) - ;; (equal (nth 2 else) then)) - ;; (let ((res (macroexp-if `(or ,test ,(nth 1 else)) - ;; then (macroexp-progn (nthcdr 3 else))))) - ;; (message "if+if => if-or: sharing %S" then) - ;; res)) - (t - ;; (cond - ;; ((and (eq 'cond (car-safe then)) - ;; (equal `(cond ,@(nthcdr 2 then)) else)) - ;; (message "if+cond => cond-and: sharing %S" else)) - ;; ((and (eq 'cond (car-safe else)) - ;; (equal (macroexp-unprogn (macroexp-progn (cdr (nth 1 else)))) - ;; (macroexp-unprogn then))) - ;; (message "if+cond => cond-or: sharing %S" then))) - (macroexp-if test then else)))) + (t (macroexp-if test then else)))) ;; Note about MATCH: ;; When we have patterns like `(PAT1 . PAT2), after performing the `consp' @@ -953,14 +919,6 @@ QPAT can take the following forms: ((or (stringp qpat) (integerp qpat) (symbolp qpat)) `',qpat) (t (error "Unknown QPAT: %S" qpat)))) -;;; Extra definitions that use pcase. - -(defun pcase--canon (e) - (pcase e - (`(progn ,e) (pcase--canon e)) - (`(cond (,test . ,then) (t . ,else)) - `(if ,test ,(macroexp-progn then) ,(macroexp-progn else))))) - (provide 'pcase) ;;; pcase.el ends here -- 2.39.2