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;; -*-theme-d-*-
;; Copyright (C) 2016, 2021 Tommi Höynälänmaa
;; Distributed under GNU Lesser General Public License version 3,
;; see file doc/LGPL-3.
(define-interface (standard-library promise)
(import (standard-library core))
(define-param-logical-type :promise (%type)
(:procedure () %type pure))
(define-param-logical-type :nonpure-promise (%type)
(:procedure () %type nonpure))
(declare-param-method make-promise (%type)
((:procedure () %type pure))
(:promise %type)
pure)
(define-syntax delay
(syntax-rules ()
((delay expression)
(make-promise (lambda-automatic (() pure) expression)))))
(declare-param-method force (%type)
((:promise %type))
%type
pure)
(declare-param-method make-nonpure-promise (%type)
((:procedure () %type nonpure))
(:nonpure-promise %type)
pure)
(define-syntax delay-nonpure
(syntax-rules ()
((delay expression)
(make-nonpure-promise (lambda-automatic (() nonpure) expression)))))
(declare-param-method force-nonpure (%type)
((:nonpure-promise %type))
%type
nonpure))
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