diff options
Diffstat (limited to 'module/srfi')
-rw-r--r-- | module/srfi/srfi-45.scm | 21 |
1 files changed, 12 insertions, 9 deletions
diff --git a/module/srfi/srfi-45.scm b/module/srfi/srfi-45.scm index 29b0393ff..47e3ba605 100644 --- a/module/srfi/srfi-45.scm +++ b/module/srfi/srfi-45.scm @@ -1,6 +1,6 @@ ;;; srfi-45.scm -- Primitives for Expressing Iterative Lazy Algorithms -;; Copyright (C) 2010, 2011 Free Software Foundation, Inc. +;; Copyright (C) 2010, 2011, 2013 Free Software Foundation, Inc. ;; Copyright (C) 2003 André van Tonder. All Rights Reserved. ;; Permission is hereby granted, free of charge, to any person @@ -25,8 +25,8 @@ ;;; Commentary: -;; This is the code of the reference implementation of SRFI-45, slightly -;; modified to use SRFI-9. +;; This is the code of the reference implementation of SRFI-45, +;; modified to use SRFI-9 and to support multiple values. ;; This module is documented in the Guile Reference Manual. @@ -36,8 +36,9 @@ #:export (delay lazy force - eager) - #:replace (delay force) + eager + promise?) + #:replace (delay force promise?) #:use-module (srfi srfi-9)) (define-record-type promise (make-promise val) promise? @@ -50,16 +51,18 @@ (define-syntax-rule (lazy exp) (make-promise (make-value 'lazy (lambda () exp)))) -(define (eager x) - (make-promise (make-value 'eager x))) +(define (eager . xs) + (make-promise (make-value 'eager xs))) (define-syntax-rule (delay exp) - (lazy (eager exp))) + (lazy (call-with-values + (lambda () exp) + eager))) (define (force promise) (let ((content (promise-val promise))) (case (value-tag content) - ((eager) (value-proc content)) + ((eager) (apply values (value-proc content))) ((lazy) (let* ((promise* ((value-proc content))) (content (promise-val promise))) ; * (if (not (eqv? (value-tag content) 'eager)) ; * |