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+;;; "comparse.scm" Break command line into arguments.
+;Copyright (C) 1995 Aubrey Jaffer
+;
+;Permission to copy this software, to redistribute it, 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.
+
+(require 'string-port)
+(define (read-command . port)
+ (define argv '())
+ (define obj "")
+ (define chars '())
+ (define eof #f)
+ (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 goto)
+ (readc)
+ (cond ((char=? #\newline (peekc)) (readc) (goto (peekc)))
+ (else (set! chars (cons (readc) 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) (char=? #\newline c) c))))
+ ((#\; #\newline) (readc))
+ (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 build-token
+ (lambda (c)
+ (case c
+ ((#\") (splice-arg (read port)))
+ ((#\() (s-expression))
+ ((#\\) (backslash build-token))
+ ((#\newline #\;)
+ (readc)
+ (set! argv (cons (string-append
+ obj (list->string (reverse chars)))
+ argv)))
+ (else
+ (cond ((or (eof-object? c)
+ (char-whitespace? c))
+ (readc)
+ (set! argv (cons (string-append
+ obj (list->string (reverse chars)))
+ argv))
+ (set! obj "")
+ (set! chars '())
+ (loop (peekc)))
+ (else (set! chars (cons (readc) chars))
+ (build-token (peekc))))))))
+ (set! port
+ (cond ((null? port) (current-input-port))
+ ((= 1 (length port)) (car port))
+ (else
+ (slib:error
+ 'read-command-line
+ "Wrong Number of ARGs:"
+ port))))
+ (let ((c (loop (peekc))))
+ (cond ((and (null? argv) (eof-object? c)) c)
+ (else (reverse argv)))))