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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-body (standard-library stream)
(define-param-method stream-next (%type)
(((stream (:stream %type)))
(:stream %type)
pure)
(match-type stream
((<null>) (raise-simple 'stream-next:empty-stream))
((stream2 (:nonempty-stream %type))
(force (cdr stream2)))))
(define-param-method stream-value (%type)
(((stream (:stream %type)))
%type
pure)
(match-type stream
((<null>) (raise-simple 'stream-value:empty-stream))
((stream2 (:nonempty-stream %type))
(force (car stream2)))))
(define-param-method stream-empty? (%type)
(((stream (:stream %type)))
<boolean>
pure)
(null? stream))
(define-param-method stream->list (%type)
(((stream (:stream %type)))
(:uniform-list %type)
pure)
(match-type stream
((<null>) null)
((stream2 (:nonempty-stream %type))
(cons (force (car stream2))
(stream->list (stream-next stream2))))))
(define-param-method list->stream (%type)
(((l (:uniform-list %type)))
(:stream %type)
pure)
(match-type l
((<null>) null)
((l2 (:nonempty-uniform-list %type))
(cons (delay (car l2)) (delay (list->stream (cdr l2)))))))
(define-param-method nonpure-stream-next (%type)
(((stream (:nonpure-stream %type)))
(:nonpure-stream %type)
nonpure)
(match-type stream
((<null>) (raise-simple 'nonpure-stream-next:empty-stream))
((stream2 (:nonempty-nonpure-stream %type))
(force-nonpure (cdr stream2)))))
(define-param-method nonpure-stream-value (%type)
(((stream (:nonpure-stream %type)))
%type
nonpure)
(match-type stream
((<null>) (raise-simple 'nonpure-stream-value:empty-stream))
((stream2 (:nonempty-nonpure-stream %type))
(force-nonpure (car stream2)))))
(define-param-method nonpure-stream-empty? (%type)
(((stream (:nonpure-stream %type)))
<boolean>
pure)
(null? stream))
(define-param-method nonpure-stream->list (%type)
(((stream (:nonpure-stream %type)))
(:uniform-list %type)
nonpure)
(match-type stream
((<null>) null)
((stream2 (:nonempty-nonpure-stream %type))
(cons (force-nonpure (car stream2))
(nonpure-stream->list
(nonpure-stream-next stream2))))))
(define-param-method stream-map (%type1 %type2)
(((proc (:procedure (%type1) %type2 pure))
(stm (:stream %type1)))
(:stream %type2)
pure)
(match-type stm
((<null>) null)
((stm2 (:nonempty-stream %type1))
(cons (delay (proc (force (car stm2))))
(delay (stream-map proc (stream-next stm2)))))))
(define-param-method stream-map-nonpure (%type1 %type2)
(((proc (:procedure (%type1) %type2 nonpure))
(stm (:stream %type1)))
(:nonpure-stream %type2)
nonpure)
(match-type stm
((<null>) null)
((stm2 (:nonempty-stream %type1))
(cons (delay-nonpure (proc (force (car stm2))))
(delay-nonpure
(stream-map-nonpure proc (stream-next stm2)))))))
(define-param-method stream-for-each (%type1)
(((proc (:procedure (%type1) <none> nonpure))
(stm (:stream %type1)))
<none>
nonpure)
(match-type stm
((<null>) null)
((stm2 (:nonempty-stream %type1))
(proc (stream-value stm2))
(stream-for-each proc (stream-next stm2)))))
(define-param-method nonpure-stream-map (%type1 %type2)
(((proc (:procedure (%type1) %type2 nonpure))
(stm (:nonpure-stream %type1)))
(:nonpure-stream %type2)
nonpure)
(match-type stm
((<null>) null)
((stm2 (:nonempty-nonpure-stream %type1))
(cons (delay-nonpure (proc (force-nonpure (car stm2))))
(delay-nonpure
(nonpure-stream-map proc (nonpure-stream-next stm2)))))))
(define-param-method nonpure-stream-for-each (%type1)
(((proc (:procedure (%type1) <none> nonpure))
(stm (:nonpure-stream %type1)))
<none>
nonpure)
(match-type stm
((<null>) null)
((stm2 (:nonempty-nonpure-stream %type1))
(proc (force-nonpure (car stm2)))
(nonpure-stream-for-each proc (nonpure-stream-next stm2)))))
(define-simple-method make-input-expr-stream
(((ip <input-port>)) (:nonpure-stream <object>) nonpure)
(if (eof? (peek-character ip))
null
(cons (delay-nonpure (read ip))
(delay-nonpure (make-input-expr-stream ip))))))
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