107 lines
3.6 KiB
Scheme
107 lines
3.6 KiB
Scheme
;;; Ikarus Scheme -- A compiler for R6RS Scheme.
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;;; Copyright (C) 2006,2007 Abdulaziz Ghuloum
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;;;
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;;; This program is free software: you can redistribute it and/or modify
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;;; it under the terms of the GNU General Public License version 3 as
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;;; published by the Free Software Foundation.
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;;;
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;;; This program is distributed in the hope that it will be useful, but
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;;; 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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;;; General Public License for more details.
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;;;
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;;; You should have received a copy of the GNU General Public License
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;;; along with this program. If not, see <http://www.gnu.org/licenses/>.
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(library (ikarus io input-strings)
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(export open-string-input-port)
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(import
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(ikarus system $strings)
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(ikarus system $bytevectors)
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(ikarus system $fx)
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(ikarus system $pairs)
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(ikarus system $ports)
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(ikarus system $io)
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(except (ikarus) open-string-input-port ))
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(define-syntax message-case
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(syntax-rules (else)
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[(_ msg args
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[(msg-name msg-arg* ...) b b* ...] ...
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[else else1 else2 ...])
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(let ([tmsg msg] [targs args])
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(define-syntax match-and-bind
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(syntax-rules ()
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[(__ y () body)
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(if (null? y)
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body
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(error 'message-case "unmatched" (cons tmsg targs)))]
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[(__ y (a a* (... ...)) body)
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(if (pair? y)
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(let ([a (car y)] [d (cdr y)])
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(match-and-bind d (a* (... ...)) body))
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(error 'message-case "unmatched" (cons tmsg targs)))]))
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(case tmsg
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[(msg-name)
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(match-and-bind targs (msg-arg* ...) (begin b b* ...))] ...
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[else else1 else2 ...]))]))
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(define make-input-string-handler
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(lambda (str)
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(let ((open? #t) (idx 0) (n (string-length str)))
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(lambda (msg . args)
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(message-case msg args
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[(read-char p)
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(if ($fx< idx n)
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(let ([c ($string-ref str idx)])
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(set! idx ($fxadd1 idx))
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c)
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(if open?
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(eof-object)
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(error 'read-char "port is closed" p)))]
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[(peek-char p)
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(if ($fx< idx n)
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($string-ref str idx)
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(if open?
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(eof-object)
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(error 'peek-char "port is closed" p)))]
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[(port-name p) '*string-port*]
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[(close-port p)
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(when open?
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(set! open? #f))]
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[else
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(error 'input-string-handler
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"message not handled" (cons msg args))])))))
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(define ($open-input-string str)
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(let ([port (make-input-port
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(make-input-string-handler str)
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'#vu8())])
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port))
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;(define open-input-string
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; (lambda (str)
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; (unless (string? str)
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; (error 'open-input-string "not a string" str))
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; ($open-input-string str)))
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(define open-string-input-port
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(lambda (str)
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(unless (string? str)
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(error 'open-string-input-port "not a string" str))
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($open-input-string str)))
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;(define with-input-from-string
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; (lambda (str proc)
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; (unless (string? str)
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; (error 'with-input-from-string "not a string" str))
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; (unless (procedure? proc)
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; (error 'with-input-from-string "not a procedure" proc))
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; (let ([p ($open-input-string str)])
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; (parameterize ([current-input-port p])
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; (proc)))))
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)
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