; Portions Copyright 2003 Sun Microsystems, Inc.; Portions Copyright 1999-2003 Language Technologies Institute,; Carnegie Mellon University.; All Rights Reserved.  Use is subject to license terms.;; See the file "license.terms" for information on usage and; redistribution of this file, and for a DISCLAIMER OF ALL; WARRANTIES.;; Note: The variable t is the value true, but casts to the string "t" and is;        used that way in places.  nil is false.;       I think consp is the list? function.;       Replace the sun_string<? function when the scheme interpretor had;        a built-in equivalent.  (awb suggested this will happen).;       ; used to compare two lists by their first elements which are strings(define (carstring<? e1 e2);[[[TODO: sun_string<? replace with string<? when function becomes available in;  interpreter.]]]    (sun_string<? (car e1) (car e2))); used to compare two lists by their first elements which are strings(define (carstring=? e1 e2)    (string-equal (car e1) (car e2))); quicksort a list l based on two comparison operations < and ==.; stable sort(define (qsort l cmp<? cmp=?)    ; return three lists, a leftpart, the pivotlist and a rightpart    ; pivot list is a list of elements where element cmp=? pivot    (define (split l pivot leftlist pivotlist rightlist)        (cond            ((null? l)                (list leftlist pivotlist rightlist))            ((cmp=? (car l) pivot)              (split (cdr l) pivot                leftlist (append pivotlist (list (car l))) rightlist))            ((cmp<? (car l) pivot)              (split (cdr l) pivot                (append leftlist (list (car l))) pivotlist rightlist))            (t (split (cdr l) pivot                leftlist pivotlist (append rightlist (list (car l)))))    ))    (cond        ((< (length l) 3) ; base case         (cond            ((cdr l) ; if l has two entries                (if (cmp<? (car l) (cadr l))                    l                    (append (cdr l) (list (car l)))))            (t l))        )        (t (let ((pivot (nth (/ (length l) 2) l)))             (let ((newlists (split l pivot nil nil nil)))               (append (qsort (car newlists) cmp<? cmp=?)                    (cadr newlists)                    (qsort (caddr newlists) cmp<? cmp=?)))))    )); This function may be implemented by the interpretor in future versions;[[[TODO: replace used of sun_string<? with string<? when function; becomes available in interpreter.]]](define (sun_string<? str1 str2)    (define (char->int char)        (cond            ((string-equal char "") 45) ((string-equal char "_") 95)            ((string-equal char "0") 48) ((string-equal char "1") 49)            ((string-equal char "2") 50) ((string-equal char "3") 51)            ((string-equal char "4") 52) ((string-equal char "5") 53)            ((string-equal char "6") 54) ((string-equal char "7") 55)            ((string-equal char "8") 56) ((string-equal char "9") 57)            ((string-equal char "?") 63) ((string-equal char "@") 64)            ((string-equal char "A") 65) ((string-equal char "a") 97)            ((string-equal char "B") 66) ((string-equal char "b") 98)            ((string-equal char "C") 67) ((string-equal char "c") 99)            ((string-equal char "D") 68) ((string-equal char "d") 100)            ((string-equal char "E") 69) ((string-equal char "e") 101)            ((string-equal char "F") 70) ((string-equal char "f") 102)            ((string-equal char "G") 71) ((string-equal char "g") 103)            ((string-equal char "H") 72) ((string-equal char "h") 104)            ((string-equal char "I") 73) ((string-equal char "i") 105)            ((string-equal char "J") 74) ((string-equal char "j") 106)            ((string-equal char "K") 75) ((string-equal char "k") 107)            ((string-equal char "L") 76) ((string-equal char "l") 108)            ((string-equal char "M") 77) ((string-equal char "m") 109)            ((string-equal char "N") 78) ((string-equal char "n") 110)            ((string-equal char "O") 79) ((string-equal char "o") 111)            ((string-equal char "P") 80) ((string-equal char "p") 112)            ((string-equal char "Q") 81) ((string-equal char "q") 113)            ((string-equal char "R") 82) ((string-equal char "r") 114)            ((string-equal char "S") 83) ((string-equal char "s") 115)            ((string-equal char "T") 84) ((string-equal char "t") 116)            ((string-equal char "U") 85) ((string-equal char "u") 117)            ((string-equal char "V") 86) ((string-equal char "v") 118)            ((string-equal char "W") 87) ((string-equal char "w") 119)            ((string-equal char "X") 88) ((string-equal char "x") 120)            ((string-equal char "Y") 89) ((string-equal char "y") 121)            ((string-equal char "Z") 90) ((string-equal char "z") 122)	    ((string-equal char ":") 58) ((string-equal char "