ikarus/scheme/ikarus.io-primitives.ss

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;;; Ikarus Scheme -- A compiler for R6RS Scheme.
;;; Copyright (C) 2006,2007 Abdulaziz Ghuloum
;;;
;;; This program is free software: you can redistribute it and/or modify
;;; it under the terms of the GNU General Public License version 3 as
;;; published by the Free Software Foundation.
;;;
;;; This program is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
;;; General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with this program. If not, see <http://www.gnu.org/licenses/>.
(library (ikarus io-primitives)
(export read-char unread-char peek-char write-char write-byte newline
port-name input-port-name output-port-name
close-input-port reset-input-port!
flush-output-port close-output-port get-line)
(import
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(ikarus system $io)
(ikarus system $fx)
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(ikarus system $ports)
(except (ikarus) read-char unread-char peek-char write-char
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write-byte
newline port-name input-port-name output-port-name
close-input-port reset-input-port! flush-output-port
close-output-port get-line))
(define write-char
(case-lambda
[(c)
(if (char? c)
($write-char c (current-output-port))
(error 'write-char "not a character" c))]
[(c p)
(if (char? c)
(if (output-port? p)
($write-char c p)
(error 'write-char "not an output-port" p))
(error 'write-char "not a character" c))]))
(define write-byte
(case-lambda
[(b)
(if (and (fixnum? b) ($fx<= 0 b) ($fx<= b 255))
($write-byte b (current-output-port))
(error 'write-byte "not a byte" b))]
[(b p)
(if (and (fixnum? b) ($fx<= 0 b) ($fx<= b 255))
(if (output-port? p)
($write-byte b p)
(error 'write-byte "not an output-port" p))
(error 'write-byte "not a byte" b))]))
;;;
(define newline
(case-lambda
[()
($write-char #\newline (current-output-port))
($flush-output-port (current-output-port))]
[(p)
(if (output-port? p)
(begin
($write-char #\newline p)
($flush-output-port p))
(error 'newline "not an output port" p))]))
;;;
(define port-name
(lambda (p)
(if (port? p)
(($port-handler p) 'port-name p)
(error 'port-name "not a port" p))))
(define input-port-name
(lambda (p)
(if (port? p)
(($port-handler p) 'port-name p)
(error 'input-port-name "not a port" p))))
(define output-port-name
(lambda (p)
(if (port? p)
(($port-handler p) 'port-name p)
(error 'output-port-name "not a port" p))))
(define read-char
(case-lambda
[() ($read-char (current-input-port))]
[(p)
(if (input-port? p)
($read-char p)
(error 'read-char "not an input-port" p))]))
;;;
(define unread-char
(case-lambda
[(c) (if (char? c)
($unread-char c (current-input-port))
(error 'unread-char "not a character" c))]
[(c p)
(if (input-port? p)
(if (char? c)
($unread-char c p)
(error 'unread-char "not a character" c))
(error 'unread-char "not an input-port" p))]))
;;;
(define peek-char
(case-lambda
[() ($peek-char (current-input-port))]
[(p)
(if (input-port? p)
($peek-char p)
(error 'peek-char "not an input-port" p))]))
;;;
(define reset-input-port!
(case-lambda
[() ($reset-input-port! (current-input-port))]
[(p)
(if (input-port? p)
($reset-input-port! p)
(error 'reset-input-port! "not an input-port" p))]))
;;;
(define close-input-port
(case-lambda
[() ($close-input-port (current-input-port))]
[(p)
(if (input-port? p)
($close-input-port p)
(error 'close-input-port! "not an input-port" p))]))
;;;
(define close-output-port
(case-lambda
[() ($close-output-port (current-output-port))]
[(p)
(if (output-port? p)
($close-output-port p)
(error 'close-output-port "not an output-port" p))]))
;;;
(define flush-output-port
(case-lambda
[() ($flush-output-port (current-output-port))]
[(p)
(if (output-port? p)
($flush-output-port p)
(error 'flush-output-port "not an output-port" p))]))
(define (get-line p)
(define (get-it p)
(let f ([p p] [n 0] [ac '()])
(let ([x ($read-char p)])
(cond
[(eqv? x #\newline)
(make-it n ac)]
[(eof-object? x)
(if (null? ac) x (make-it n ac))]
[else (f p (+ n 1) (cons x ac))]))))
(define (make-it n revls)
(let f ([s (make-string n)] [i (- n 1)] [ls revls])
(cond
[(pair? ls)
(string-set! s i (car ls))
(f s (- i 1) (cdr ls))]
[else s])))
(if (input-port? p)
(get-it p)
(error 'get-line "not an input port" p)))
)