71 lines
2.3 KiB
Scheme
71 lines
2.3 KiB
Scheme
;;;; textual-ports.scm --- Textual I/O on ports
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;;;; Copyright (C) 2016 Free Software Foundation, Inc.
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;;;;
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;;;; This library is free software; you can redistribute it and/or
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;;;; modify it under the terms of the GNU Lesser General Public
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;;;; License as published by the Free Software Foundation; either
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;;;; version 3 of the License, or (at your option) any later version.
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;;;;
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;;;; This library is distributed in the hope that it will be useful,
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;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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;;;; Lesser General Public License for more details.
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;;;;
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;;;; You should have received a copy of the GNU Lesser General Public
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;;;; License along with this library; if not, write to the Free Software
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;;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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;;; Commentary:
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;;;
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;;; Code:
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(define-module (ice-9 textual-ports)
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#:use-module (ice-9 ports internal)
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#:use-module (ice-9 binary-ports)
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#:use-module (ice-9 rdelim)
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#:re-export (get-string-n!
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put-char
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put-string)
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#:export (get-char
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unget-char
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unget-string
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lookahead-char
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get-string-n
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get-string-all
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get-line))
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(define (get-char port)
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(read-char port))
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(define (lookahead-char port)
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(peek-char port))
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(define (unget-char port char)
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(unread-char char port))
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(define* (unget-string port string #:optional (start 0)
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(count (- (string-length string) start)))
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(unread-string (if (and (zero? start)
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(= count (string-length string)))
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string
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(substring/shared string start (+ start count)))
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port))
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(define (get-line port)
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(read-line port 'trim))
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(define (get-string-all port)
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(read-string port))
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(define (get-string-n port count)
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"Read up to @var{count} characters from @var{port}.
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If no characters could be read before encountering the end of file,
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return the end-of-file object, otherwise return a string containing
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the characters read."
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(let* ((s (make-string count))
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(rv (get-string-n! port s 0 count)))
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(cond ((eof-object? rv) rv)
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((= rv count) s)
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(else (substring/shared s 0 rv)))))
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