diff options
Diffstat (limited to 'lisp/emacs-lisp/pcase.el')
| -rw-r--r-- | lisp/emacs-lisp/pcase.el | 38 |
1 files changed, 22 insertions, 16 deletions
diff --git a/lisp/emacs-lisp/pcase.el b/lisp/emacs-lisp/pcase.el index 03d760b2df..b2b27a0e0d 100644 --- a/lisp/emacs-lisp/pcase.el +++ b/lisp/emacs-lisp/pcase.el @@ -1,6 +1,6 @@ ;;; pcase.el --- ML-style pattern-matching macro for Elisp -;; Copyright (C) 2010 Stefan Monnier +;; Copyright (C) 2010 Free Software Foundation, Inc. ;; Author: Stefan Monnier <[email protected]> ;; Keywords: @@ -290,9 +290,13 @@ MATCH is the pattern that needs to be matched, of the form: (defun pcase-split-memq (elems pat) ;; Based on pcase-split-eq. (cond - ;; The same match will give the same result. + ;; The same match will give the same result, but we don't know how + ;; to check it. + ;; (??? + ;; (cons :pcase-succeed nil)) + ;; A match for one of the elements may succeed or fail. ((and (eq (car-safe pat) '\`) (member (cadr pat) elems)) - (cons :pcase-succeed nil)) + nil) ;; A different match will fail if this one succeeds. ((and (eq (car-safe pat) '\`) ;; (or (integerp (cadr pat)) (symbolp (cadr pat)) @@ -383,18 +387,20 @@ and otherwise defers to REST which is a list of branches of the form `(,(cadr upat) ,sym) (let* ((exp (cadr upat)) ;; `vs' is an upper bound on the vars we need. - (vs (pcase-fgrep (mapcar #'car vars) exp))) - (if vs - ;; Let's not replace `vars' in `exp' since it's - ;; too difficult to do it right, instead just - ;; let-bind `vars' around `exp'. - `(let ,(mapcar (lambda (var) - (list var (cdr (assq var vars)))) - vs) - ;; FIXME: `vars' can capture `sym'. E.g. - ;; (pcase x ((and `(,x . ,y) (pred (fun x))))) - (,@exp ,sym)) - `(,@exp ,sym)))) + (vs (pcase-fgrep (mapcar #'car vars) exp)) + (call (if (functionp exp) + `(,exp ,sym) `(,@exp ,sym)))) + (if (null vs) + call + ;; Let's not replace `vars' in `exp' since it's + ;; too difficult to do it right, instead just + ;; let-bind `vars' around `exp'. + `(let ,(mapcar (lambda (var) + (list var (cdr (assq var vars)))) + vs) + ;; FIXME: `vars' can capture `sym'. E.g. + ;; (pcase x ((and `(,x . ,y) (pred (fun x))))) + ,call)))) (pcase-u1 matches code vars then-rest) (pcase-u else-rest)))) ((symbolp upat) @@ -483,7 +489,7 @@ and if not, defers to REST which is a list of branches of the form (pcase-u1 matches code vars then-rest) (pcase-u else-rest)))) (t (error "Unkown QPattern %s" qpat)))) - + (provide 'pcase) ;;; pcase.el ends here |