summaryrefslogtreecommitdiffstats
path: root/syntest2.scm
blob: 68633cfc0cee896b7d059ae5517ec9f4561381c5 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
;; Copyright (C) 2000, 2001, 2002 Free Software Foundation, Inc.
;;
;; This program is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.
;;
;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.
;;
;; You should have received a copy of the GNU General Public License
;; along with this software; see the file COPYING.  If not, write to
;; the Free Software Foundation, 59 Temple Place, Suite 330, Boston, MA 02111, USA.
;;
;; As a special exception, the Free Software Foundation gives permission
;; for additional uses of the text contained in its release of GUILE.
;;
;; The exception is that, if you link the GUILE library with other files
;; to produce an executable, this does not by itself cause the
;; resulting executable to be covered by the GNU General Public License.
;; Your use of that executable is in no way restricted on account of
;; linking the GUILE library code into it.
;;
;; This exception does not however invalidate any other reasons why
;; the executable file might be covered by the GNU General Public License.
;;
;; This exception applies only to the code released by the
;; Free Software Foundation under the name GUILE.  If you copy
;; code from other Free Software Foundation releases into a copy of
;; GUILE, as the General Public License permits, the exception does
;; not apply to the code that you add in this way.  To avoid misleading
;; anyone as to the status of such modified files, you must delete
;; this exception notice from them.
;;
;; If you write modifications of your own for GUILE, it is your choice
;; whether to permit this exception to apply to your modifications.
;; If you do not wish that, delete this exception notice.

(require 'macro)

;; Redefine some derived special forms.

(define-syntax let
  (syntax-rules ()
    ((let ((?name ?val) ...) . ?body)
     ((lambda (?name ...) . ?body) ?val ...))
    ((let ?proc ((?name ?val) ...) . ?body)
     (let ((?proc #f)
	   (?name ?val) ...)
       (set! ?proc (lambda (?name ...) . ?body))
       (?proc ?name ...)))))

(define-syntax let*
  (syntax-rules ()
    ((let* () . ?body)
     ((lambda () . ?body)))
    ((let* ((?name ?val)) . ?body)
     ((lambda (?name) . ?body) ?val))
    ((let* ((?name ?val) ?binding ...) . ?body)
     (let* ((?name ?val))
       (let* (?binding ...) . ?body)))))

(define-syntax letrec
  (syntax-rules ()
    ((letrec ((?name ?val) ...) . ?body)
     (let ((?name #f) ...)
       (set! ?name ?val) ...
       (let () . ?body)))))

(define-syntax and
  (syntax-rules ()
    ((and) #t)
    ((and ?exp)
     (let ((x ?exp))
       (if x x #f)))
    ((and ?exp . ?rest)
     (let ((x ?exp))
       (if x (and . ?rest) #f)))))

(define-syntax or
  (syntax-rules ()
    ((or) #f)
    ((or ?exp)
     (let ((x ?exp))
       (if x x #f)))
    ((or ?exp . ?rest)
     (let ((x ?exp))
       (if x x (or . ?rest))))))

(define (force promise)
  (promise))

(define (make-promise proc)
  (let ((result #f))
    (lambda ()
      (if result (car result)
	  (let ((x (proc)))
	    (if result (car result)
		(begin (set! result (list x))
		       x)))))))

(define-syntax delay
  (syntax-rules ()
    ((delay ?expr)
     (make-promise (lambda () ?expr)))))

(define-syntax do
  (syntax-rules ()
    ((do ((?name ?init . ?step) ...)
	 (?test . ?result)
       ?body ...)
     (let-syntax ((do-step (syntax-rules ()
			     ((do-step ?n) ?n)
			     ((do-step ?n ?s) ?s)))
		  (do-result (syntax-rules ()
			       ((do-result) (if #f #f))
			       ((do-result . ?r) (begin . ?r)))))
       (let loop ((?name ?init) ...)
	 (if ?test
	     (do-result . ?result)
	     (begin ?body ...
		    (loop (do-step ?name . ?step) ...))))))))

(define-syntax case
  (syntax-rules (else)
    ((case ?x (else . ?conseq))
     (begin . ?conseq))
    ((case ?x (?lst . ?conseq))
     (if (memv ?x '?lst) (begin . ?conseq)))
    ((case ?x (?lst . ?conseq) . ?rest)
     (if (memv ?x '?lst)
	 (begin . ?conseq)
	 (case ?x . ?rest)))))

(define-syntax cond
  (syntax-rules (else =>)
    ((cond ?clause0 . ?clauses)
     (letrec-syntax 
	 ((cond-aux
	   (syntax-rules (else =>)
	     ((cond-aux) (if #f #f))
	     ((cond-aux (else . ?conseq))
	      (begin . ?conseq))
	     ((cond-aux (?test => ?proc) . ?rest)
	      (let ((val ?test))
		(if val (?proc val) (cond-aux . ?rest))))
	     ((cond-aux (?test) . ?rest)
	      (or ?test (cond-aux . ?rest)))
	     ((cond-aux (?test . ?conseq) . ?rest)
	      (if ?test (begin . ?conseq) (cond-aux . ?rest))))))
       (cond-aux ?clause0 . ?clauses)))))

;; This may fail if you redefine CONS, LIST, APPEND, or LIST->VECTOR
;; It uses the (... ...) escape.
;; All forms are evaluated inside a LETREC-SYNTAX body (is this a problem?).

(define-syntax quasiquote
  (syntax-rules ()
    ((_ ?template)
     (letrec-syntax
	 ((qq
	   (syntax-rules (unquote unquote-splicing quasiquote)
	     ((_ (unquote ?form) ())
	      ?form)
	     ((_ (unquote ?form) (?depth))
	      (list 'unquote (qq ?form ?depth)))
	     ((_ (quasiquote ?form) ?depth)
	      (list 'quasiquote (qq ?form (?depth))))
	     ((_ ((unquote-splicing ?form) . ?rest) ())
	      (append ?form (qq ?rest ())))
	     ((_ ((unquote-splicing ?form) . ?rest) (?depth))
	      (append (list 'unquote-splicing (qq ?form ?depth))
		      (qq ?rest (?depth))))
	     ((_ (?car . ?cdr) ?depth)
	      (cons (qq ?car ?depth) (qq ?cdr ?depth)))
	     ((_ #(?elt (... ...)) ?depth)
	      (list->vector (qq (?elt (... ...)) ?depth)))
	     ((_ ?atom ?depth)
	      '?atom))))
       (qq ?template ())))))

;;(load "r4rstest.scm")