;;; Snow-repository.scm - Snow implementation
;;;
;;; Copyright (c) 2012 Johan Ceuppens
;;;
;;; All rights reserved.
;;;
;;; Redistribution and use in source and binary forms, with or without
;;; modification, are permitted provided that the following conditions
;;; are met:
;;; 1. Redistributions of source code must retain the above copyright
;;;    notice, this list of conditions and the following disclaimer.
;;; 2. Redistributions in binary form must reproduce the above copyright
;;;    notice, this list of conditions and the following disclaimer in the
;;;    documentation and/or other materials provided with the distribution.
;;; 3. The name of the authors may not be used to endorse or promote products
;;;    derived from this software without specific prior written permission.
;;;
;;; THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
;;; IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
;;; OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
;;; IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
;;; INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
;;; NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
;;; DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
;;; THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
;;; (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
;;; THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

(define (parse-for s index)
  (let ((word "("))
    (do ((i index (+ i 1)))
        ((cond ((string=? s word)
                ;;(set! index i))
                i)
               ((eq? (string-ref s i) #\newline)
                #t));;(string-set! s i ""
         (set! word (string-append word (string (string-ref s i))))))))


(define (parse-for-url s index)
  (let ((word "")
        (index (+ index 1)))
    (if (eq? (string-ref s (- index 1))
             #\")
        (do ((i index (+ i 1)))
            ((eq? (string-ref s i) #\")
             (string-append s (string #\")))
          (set! word (string-append word (string (string-ref s i)))))
        (error "parse-for-url : malformed url string"))))

(define (snow-repository db)
  (let ((index 0)
        (db db))
    (cond ((let ((index2 (parse-for "repository" index)))
             (cond ((let ((index3 (parse-for "package" index2))))
                    (cond ((let ((index4 (parse-for "url" index3))))
                           ((cond (let ((url parse-for-url index4))))
                            (set! db (append db (cons "url" url)
                                             ))))))))))))