53 lines
1.5 KiB
Scheme
53 lines
1.5 KiB
Scheme
; Copyright (c) 1993-1999 by Richard Kelsey and Jonathan Rees. See file COPYING.
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; Provides input and output channels.
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(define (input-channel? thing)
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(and (channel? thing)
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(or (= (channel-status thing)
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(enum channel-status-option input))
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(= (channel-status thing)
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(enum channel-status-option special-input)))))
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(define (output-channel? thing)
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(and (channel? thing)
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(or (= (channel-status thing)
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(enum channel-status-option output))
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(= (channel-status thing)
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(enum channel-status-option special-output)))))
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;;; Scsh changes umask and cwd lazily
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;;; placeholder until scsh sets it
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(define (with-fs-context-aligned* thunk)
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(thunk))
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(define (set-with-fs-context-aligned*! wpca*)
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(set! with-fs-context-aligned* wpca*))
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(define (open-input-channel filename)
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(let ((channel (with-fs-context-aligned*
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(lambda ()
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(open-channel filename (enum channel-status-option input))))))
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(if (channel? channel)
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channel
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(error "cannot open input file" filename))))
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(define (open-output-channel filename)
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(let ((channel (with-fs-context-aligned*
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(lambda ()
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(open-channel filename (enum channel-status-option output))))))
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(if (channel? channel)
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channel
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(error "cannot open output file" filename))))
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(define (close-input-channel channel)
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(if (input-channel? channel)
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(close-channel channel)
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(call-error close-input-channel channel)))
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(define (close-output-channel channel)
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(if (output-channel? channel)
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(close-channel channel)
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(call-error close-output-channel channel)))
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