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;;; "comparse.scm" Break command line into arguments.
;Copyright (C) 1995, 1997 Aubrey Jaffer
;
;Permission to copy this software, to modify it, to redistribute it,
;to distribute modified versions, and to use it for any purpose is
;granted, subject to the following restrictions and understandings.
;
;1. Any copy made of this software must include this copyright notice
;in full.
;
;2. I have made no warrantee or representation that the operation of
;this software will be error-free, and I am under no obligation to
;provide any services, by way of maintenance, update, or otherwise.
;
;3. In conjunction with products arising from the use of this
;material, there shall be no use of my name in any advertising,
;promotional, or sales literature without prior written consent in
;each case.
;;;; This is a simple command-line reader. It could be made fancier
;;; to handle lots of `shell' syntaxes.
;;; Albert L. Ting points out that a similar process can be used for
;;; reading files of options -- therefore READ-OPTIONS-FILE.
(require 'string-port)
(define (read-command-from-port port nl-term?)
(define argv '())
(define obj "")
(define chars '())
(define readc (lambda () (read-char port)))
(define peekc (lambda () (peek-char port)))
(define s-expression
(lambda ()
(splice-arg (call-with-output-string
(lambda (p) (display (slib:eval (read port)) p))))))
(define backslash
(lambda (goto)
(readc)
(let ((c (readc)))
(cond ((eqv? #\newline c) (goto (peekc)))
((and (char-whitespace? c) (eqv? #\newline (peekc))
(eqv? 13 (char->integer c)))
(readc) (goto (peekc)))
(else (set! chars (cons c chars)) (build-token (peekc)))))))
(define loop
(lambda (c)
(case c
((#\\) (backslash loop))
((#\") (splice-arg (read port)))
((#\( #\') (s-expression))
((#\#) (do ((c (readc) (readc)))
((or (eof-object? c) (eqv? #\newline c))
(if nl-term? c (loop (peekc))))))
((#\;) (readc))
((#\newline) (readc) (and (not nl-term?) (loop (peekc))))
(else (cond ((eof-object? c) c)
((char-whitespace? c) (readc) (loop (peekc)))
(else (build-token c)))))))
(define splice-arg
(lambda (arg)
(set! obj (string-append obj (list->string (reverse chars)) arg))
(set! chars '())
(build-token (peekc))))
(define buildit
(lambda ()
(readc)
(set! argv (cons (string-append obj (list->string (reverse chars)))
argv))))
(define build-token
(lambda (c)
(case c
((#\") (splice-arg (read port)))
((#\() (s-expression))
((#\\) (backslash build-token))
((#\;) (buildit))
(else (cond ((or (eof-object? c) (char-whitespace? c))
(buildit)
(cond ((not (and nl-term? (eqv? c #\newline)))
(set! obj "")
(set! chars '())
(loop (peekc)))))
(else (set! chars (cons (readc) chars))
(build-token (peekc))))))))
(let ((c (loop (peekc))))
(cond ((and (null? argv) (eof-object? c)) c)
(else (reverse argv)))))
(define (read-command . port)
(read-command-from-port (cond ((null? port) (current-input-port))
((= 1 (length port)) (car port))
(else
(slib:error 'read-command
"Wrong Number of ARGs:" port)))
#t))
(define (read-options-file filename)
(call-with-input-file filename
(lambda (port) (read-command-from-port port #f))))
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