diff options
Diffstat (limited to 'lisp/emacs-lisp/pcase.el')
| -rw-r--r-- | lisp/emacs-lisp/pcase.el | 35 |
1 files changed, 19 insertions, 16 deletions
diff --git a/lisp/emacs-lisp/pcase.el b/lisp/emacs-lisp/pcase.el index 4706be5e57c..0e8a969a402 100644 --- a/lisp/emacs-lisp/pcase.el +++ b/lisp/emacs-lisp/pcase.el @@ -166,23 +166,26 @@ like `(,a . ,(pred (< a))) or, with more checks: ;;;###autoload (defmacro pcase-lambda (lambda-list &rest body) - "Like `lambda' but allow each argument to be a pattern. -`&rest' argument is supported." + "Like `lambda' but allow each argument to be a UPattern. +I.e. accepts the usual &optional and &rest keywords, but every +formal argument can be any pattern accepted by `pcase' (a mere +variable name being but a special case of it)." (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) - ,@(car body) - (pcase ,args - (,(list '\` pats) . ,(cdr body)))))) + (debug ((&rest pcase-UPAT) body))) + (let* ((bindings ()) + (parsed-body (macroexp-parse-body body)) + (args (mapcar (lambda (pat) + (if (symbolp pat) + ;; Simple vars and &rest/&optional are just passed + ;; through unchanged. + pat + (let ((arg (make-symbol + (format "arg%s" (length bindings))))) + (push `(,pat ,arg) bindings) + arg))) + lambda-list))) + `(lambda ,args ,@(car parsed-body) + (pcase-let* ,(nreverse bindings) ,@(cdr parsed-body))))) (defun pcase--let* (bindings body) (cond |