diff options
Diffstat (limited to 'lisp/emacs-lisp/generator.el')
| -rw-r--r-- | lisp/emacs-lisp/generator.el | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/lisp/emacs-lisp/generator.el b/lisp/emacs-lisp/generator.el index 506df59d8e2..e38c7d91096 100644 --- a/lisp/emacs-lisp/generator.el +++ b/lisp/emacs-lisp/generator.el @@ -567,8 +567,11 @@ modified copy." (unless ,normal-exit-symbol ,@unwind-forms)))))) -(put 'iter-end-of-sequence 'error-conditions '(iter-end-of-sequence)) -(put 'iter-end-of-sequence 'error-message "iteration terminated") +(define-error 'iter-end-of-sequence "Iteration terminated" + ;; FIXME: This was not defined originally as an `error' condition, so + ;; we reproduce this by passing itself as the parent, which avoids the + ;; default `error' parent. Maybe it *should* be in the `error' category? + 'iter-end-of-sequence) (defun cps--make-close-iterator-form (terminal-state) (if cps--cleanup-table-symbol @@ -700,6 +703,14 @@ of values. Callers can retrieve each value using `iter-next'." `(lambda ,arglist ,(cps-generate-evaluator body))) +(defmacro iter-make (&rest body) + "Return a new iterator." + (declare (debug t)) + (cps-generate-evaluator body)) + +(defconst iter-empty (lambda (_op _val) (signal 'iter-end-of-sequence nil)) + "Trivial iterator that always signals the end of sequence.") + (defun iter-next (iterator &optional yield-result) "Extract a value from an iterator. YIELD-RESULT becomes the return value of `iter-yield' in the |