44 lines
1.5 KiB
Scheme
44 lines
1.5 KiB
Scheme
;; Copyright (c) 2009 Derick Eddington. All rights reserved.
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;; Licensed under an MIT-style license. My license is in the file
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;; named LICENSE from the original collection this file is distributed
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;; with. If this file is redistributed with some other collection, my
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;; license must also be included.
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#!r6rs
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(library (srfi s6 basic-string-ports)
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(export
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(rename (open-string-input-port open-input-string))
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open-output-string
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get-output-string)
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(import
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(rnrs)
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(only (scheme base) make-weak-hasheq hash-ref hash-set!))
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(define accumed-ht (make-weak-hasheq))
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(define (open-output-string)
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(letrec ([sop
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(make-custom-textual-output-port
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"string-output-port"
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(lambda (string start count) ; write!
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(when (positive? count)
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(let ([al (hash-ref accumed-ht sop)])
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(hash-set! accumed-ht sop
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(cons (substring string start (+ start count)) al))))
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count)
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#f ; get-position TODO?
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#f ; set-position! TODO?
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#f #| closed TODO? |# )])
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(hash-set! accumed-ht sop '())
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sop))
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(define (get-output-string sop)
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(if (output-port? sop)
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(cond [(hash-ref accumed-ht sop #f)
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=> (lambda (al) (apply string-append (reverse al)))]
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[else
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(assertion-violation 'get-output-string "not a string-output-port" sop)])
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(assertion-violation 'get-output-string "not an output-port" sop)))
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)
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