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Tighter pcase or-pattern member function selection (bug#36139)

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* lisp/emacs-lisp/pcase.el (pcase--u1):
Use the most specific of `memq', `memql' and `member' in or-patterns
with constant cases.  This improves performance and may help the byte-code
compiler generate a switch.
* test/lisp/emacs-lisp/pcase-tests.el (pcase-tests-member):
Add mixed-type or-pattern test cases.
This commit is contained in:
Mattias Engdegård 2019-05-21 12:19:38 +02:00
parent 36ab408207
commit b8c74742c0
2 changed files with 12 additions and 9 deletions
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15
lisp/emacs-lisp/pcase.el
View file

@ -785,25 +785,26 @@ Otherwise, it defers to REST which is a list of branches of the form
((eq 'or (caar matches))
(let* ((alts (cdar matches))
(var (if (eq (caar alts) 'match) (cadr (car alts))))
(simples '()) (others '()) (memql-ok t))
(simples '()) (others '()) (mem-fun 'memq))
(when var
(dolist (alt alts)
(if (and (eq (car alt) 'match) (eq var (cadr alt))
(let ((upat (cddr alt)))
(eq (car-safe upat) 'quote)))
(let ((val (cadr (cddr alt))))
(unless (or (integerp val) (symbolp val))
(setq memql-ok nil))
(push (cadr (cddr alt)) simples))
(cond ((integerp val)
(when (eq mem-fun 'memq)
(setq mem-fun 'memql)))
((not (symbolp val))
(setq mem-fun 'member)))
(push val simples))
(push alt others))))
(cond
((null alts) (error "Please avoid it") (pcase--u rest))
;; Yes, we can use `memql' (or `member')!
((> (length simples) 1)
(pcase--u1 (cons `(match ,var
. (pred (pcase--flip
,(if memql-ok #'memql #'member)
',simples)))
. (pred (pcase--flip ,mem-fun ',simples)))
(cdr matches))
code vars
(if (null others) rest

6
test/lisp/emacs-lisp/pcase-tests.el
View file

@ -51,9 +51,11 @@
(ert-deftest pcase-tests-member ()
(should (pcase-tests-grep
'memql (macroexpand-all '(pcase x ((or 1 2 3) body)))))
'memq (macroexpand-all '(pcase x ((or 'a 'b 'c) body)))))
(should (pcase-tests-grep
'member (macroexpand-all '(pcase x ((or "a" 2 3) body)))))
'memql (macroexpand-all '(pcase x ((or 1 2 3 'a) body)))))
(should (pcase-tests-grep
'member (macroexpand-all '(pcase x ((or "a" 2 3 'a) body)))))
(should-not (pcase-tests-grep
'memq (macroexpand-all '(pcase x ((or "a" 2 3) body)))))
(should-not (pcase-tests-grep