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Diffstat (limited to 'lisp/emacs-lisp/pcase.el')
| -rw-r--r-- | lisp/emacs-lisp/pcase.el | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/lisp/emacs-lisp/pcase.el b/lisp/emacs-lisp/pcase.el index b495793bee0..057b12894f9 100644 --- a/lisp/emacs-lisp/pcase.el +++ b/lisp/emacs-lisp/pcase.el @@ -164,6 +164,26 @@ like `(,a . ,(pred (< a))) or, with more checks: ;; FIXME: Could we add the FILE:LINE data in the error message? exp (append cases `((,x (error "No clause matching `%S'" ,x))))))) +;;;###autoload +(defmacro pcase-lambda (lambda-list &rest body) + "Like `lambda' but allow each argument to be a pattern. +`&rest' argument is supported." + (declare (doc-string 2) (indent defun) + (debug ((&rest pcase-UPAT &optional ["&rest" pcase-UPAT]) body))) + (let ((args (make-symbol "args")) + (pats (mapcar (lambda (u) + (unless (eq u '&rest) + (if (eq (car-safe u) '\`) (cadr u) (list '\, u)))) + lambda-list)) + (body (macroexp-parse-body body))) + ;; Handle &rest + (when (eq nil (car (last pats 2))) + (setq pats (append (butlast pats 2) (car (last pats))))) + `(lambda (&rest ,args) + ,@(remq nil (car body)) + (pcase ,args + (,(list '\` pats) . ,(cdr body)))))) + (defun pcase--let* (bindings body) (cond ((null bindings) (macroexp-progn body)) |