summaryrefslogtreecommitdiff
path: root/control-flow.lisp
blob: f429a1a036f142be775876a8d418fe1b26f3f6c3 (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
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
;;; -*- mode: lisp; coding: utf-8 -*-
;;; Toilet Lisp, a Common Lisp subset for the Étoilé runtime.
;;; Copyright (C) 2008  Matthias Andreas Benkard.
;;;
;;; 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 3 of the License, 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 program.  If not, see <http://www.gnu.org/licenses/>.


(in-package #:common-lisp)

(export '(identity constantly complement tagbody go block return-from
          return defconstant prog prog* macrolet flet prog1 prog2 labels
          multiple-value-bind multiple-value-list multiple-value-setq
          multiple-value-prog1 values-list))


(defun identity (x)
  x)

(defun constantly (c)
  (lambda (x)
    (declare (ignore x))
    c))

(defun complement (function)
  (lambda (x) (not (funcall function x))))


(defmacro labels ((&rest function-bindings) &body forms)
  "Look, ma, I've defined LABELS in terms of FLET!"
  `(flet ,(mapcar (lambda (x) `(,(first x) ())) function-bindings)
     (%fsetq ,@(mapcan (lambda (x)
                         `(,(first x) (lambda ,(second x) ,@(rest (rest x)))))
                       function-bindings))
     nil
     ,@forms))


(defmacro defconstant (name value &optional documentation)
  `(setq ,name ,value))


(defmacro prog1 (form &body forms)
  (let ((varsym (gensym)))
    `(let ((,varsym ,form))
       ,@forms
       ,varsym)))

(defmacro prog2 (form1 form2 &body forms)
  `(progn
     ,form1
     (prog1 ,form2
       ,@forms)))


;; FIXME: Should be (EVAL-WHEN (:compile-toplevel) ...).
(unless (boundp '+block-mapping-sym+)
  (defconstant +block-mapping-sym+ (gensym "BLOCK-NAME")))

(defmacro #.+block-mapping-sym+ () nil)

(defmacro block (block-name &body body)
  (let ((catch-tag (gensym)))
    `(macrolet ((,+block-mapping-sym+ ()
                  `(quote ,(acons ',block-name
                                  ',catch-tag
                                  (,+block-mapping-sym+)))))
       (catch ',catch-tag
         ,@body))))

(defmacro return-from (block-name &optional value &environment env)
  `(throw ',(cdr (assoc block-name (cadr (macroexpand `(,+block-mapping-sym+)
                                                      env))
                        :test 'eq))
     ,value))

(defmacro return (&optional value)
  `(return-from nil ,value))


;; FIXME: Should be (EVAL-WHEN (:compile-toplevel) ...).
(unless (boundp '+go-tag-function-mapping-sym+)
  (defconstant +go-tag-function-mapping-sym+ (gensym "GO-FUNCTION"))
  (defconstant +go-tag-catch-tag-mapping-sym+ (gensym "GO-CATCH-TAG")))

(defmacro #.+go-tag-function-mapping-sym+ () nil)
(defmacro #.+go-tag-catch-tag-mapping-sym+ () nil)

(defmacro go (tag &environment env)
  `(throw ',(cdr (assoc tag (cadr (macroexpand `(,+go-tag-catch-tag-mapping-sym+)
                                               env))
                        :test 'eq))
     (function ,(cdr (assoc tag (cadr (macroexpand `(,+go-tag-function-mapping-sym+)
                                                   env))
                            :test 'eq)))))

(defmacro tagbody (&body body)
  (let* (labels-and-catch-tags
         labels-and-functions
         (catch-tag (gensym "TAGBODY-CATCH-TAG"))
         (block-name (gensym "TAGBODY-BLOCK-NAME"))
         (return-value-sym (gensym "TAGBODY-RETURN-VALUE"))
         (end-marker (gensym "TAGBODY-END"))
         (sections
          (mapcon (let (current-label
                        accumulated-clauses
                        current-function)
                    (lambda (clause-and-rest)
                      (let ((clause (car clause-and-rest))
                            (rest (cdr clause-and-rest)))
                        (cond
                          ((atom clause)
                           (when current-function
                             (pushq (cons current-label current-function)
                                    labels-and-functions)
                             (pushq (cons current-label catch-tag)
                                    labels-and-catch-tags))
                           (let ((old-function current-function))
                             (setq current-label clause
                                   current-function (gensym "TAGBODY-SECTION"))
                             (prog1
                               `((,old-function ()
                                   ;; Yes, we generate this even when
                                   ;; OLD-FUNCTION is NIL.  In this
                                   ;; case, though, the LABELS form
                                   ;; never sees the definition.  Grep
                                   ;; for (cddr (first sections)) below
                                   ;; in order to see how we make use of
                                   ;; the generated lambda form instead.
                                   ,@(nreverse accumulated-clauses)
                                   #',current-function)
                                 ,@(when (endp rest)
                                     `((,current-function ()
                                                          ',end-marker))))
                               (setq accumulated-clauses nil))))
                          (t (pushq clause accumulated-clauses)
                             (if (endp rest)
                                 (progn
                                   (when current-function
                                     (pushq (cons current-label current-function)
                                            labels-and-functions)
                                     (pushq (cons current-label catch-tag)
                                            labels-and-catch-tags))
                                   `((,current-function ()
                                        ,@(nreverse accumulated-clauses)
                                        ',end-marker)))
                                 nil))))))
                   body)))
    `(macrolet ((,+go-tag-catch-tag-mapping-sym+ ()
                  (list 'quote
                        (list* ,@(mapcar (lambda (x) (list 'quote x))
                                         labels-and-catch-tags)
                               (,+go-tag-catch-tag-mapping-sym+))))
                (,+go-tag-function-mapping-sym+ ()
                  (list 'quote
                        (list* ,@(mapcar (lambda (x) (list 'quote x))
                                         labels-and-functions)
                               (,+go-tag-function-mapping-sym+)))))
       (labels (,@(rest sections))
         (block ,block-name
           (let (,return-value-sym)
             (%loop
               (setq ,return-value-sym
                     (catch ',catch-tag
                       (if ,return-value-sym
                           (funcall ,return-value-sym)
                           (progn ,@(cddr (first sections))))))
               (when (eq ,return-value-sym ',end-marker)
                 (return-from ,block-name nil)))))))))


(defmacro prog (bindings &body body)
  ;;FIXME: declarations
  (let ((declarations nil)
        (body body))
   `(let ,bindings
      ,@declarations
      (tagbody
        ,@body))))

(defmacro prog* (bindings &body body)
  ;;FIXME: declarations
  (let ((declarations nil)
        (body body))
   `(let* ,bindings
      ,@declarations
      (tagbody
        ,@body))))


(defmacro macrolet (bindings &body body)
  `(%macrolet ,(mapcar (lambda (binding)
                         `(,(car binding)
                            ,@(make-defmacro-body (cadr binding)
                                                  (cddr binding))))
                       bindings)
     ,@body))

(defmacro flet (bindings &body body)
  `(%flet ,(mapcar (lambda (binding)
                     `(,(car binding)
                        ,@(make-defun-body (cadr binding)
                                           (cddr binding))))
                   bindings)
     ,@body))


(defmacro multiple-value-call (function-form &rest forms)
  (let ((args `(mapcan 'identity (list ,@(mapcar (lambda (form) `(multiple-value-list ,form)))))))
    `(apply ,function-form ,args)))

;;(defmacro multiple-value-list (expression)
;;  `(multiple-value-call #'list ,expression))

(defmacro multiple-value-bind ((&rest vars) expression &body forms)
  `(destructuring-bind ,vars (multiple-value-list ,expression)
     ,@forms))

(defmacro multiple-value-setq ((&rest vars) expression)
  (let ((syms (mapcar (lambda (x) (gensym)) vars)))
    `(destructuring-bind ,syms (multiple-value-list ,expression)
       (setq ,@(mapcan #'list vars syms))
       ,(first syms))))

(defmacro multiple-value-prog1 (form &body forms)
  (let ((varsym (gensym)))
    `(let ((,varsym (multiple-value-list ,form)))
       ,@forms
       (values-list ,varsym))))

(defun values-list (list)
  (apply #'values list))


;; FIXME
(defmacro assert (form &optional places datum &rest args)
  )

;; FIXME
(defmacro check-type (thing type &rest strings)
  )

;; FIXME
(defmacro defsetf (&rest args)
  )

;; FIXME
(defun get-setf-expansion (&rest args)
  (values nil nil nil `(error "SETF not implemented") `(error "SETF not implemented")))

;; FIXME
(defmacro define-setf-expander (&rest args)
  )