Commit | Line | Data |
---|---|---|
6a4d3cfd JB |
1 | ;;;; calling.scm --- Calling Conventions |
2 | ;;;; | |
3 | ;;;; Copyright (C) 1995, 1996, 1997 Free Software Foundation, Inc. | |
4 | ;;;; | |
5 | ;;;; This program is free software; you can redistribute it and/or modify | |
6 | ;;;; it under the terms of the GNU General Public License as published by | |
7 | ;;;; the Free Software Foundation; either version 2, or (at your option) | |
8 | ;;;; any later version. | |
9 | ;;;; | |
10 | ;;;; This program is distributed in the hope that it will be useful, | |
11 | ;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | ;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | ;;;; GNU General Public License for more details. | |
14 | ;;;; | |
15 | ;;;; You should have received a copy of the GNU General Public License | |
16 | ;;;; along with this software; see the file COPYING. If not, write to | |
17 | ;;;; the Free Software Foundation, Inc., 59 Temple Place, Suite 330, | |
18 | ;;;; Boston, MA 02111-1307 USA | |
19 | ;;;; | |
20 | \f | |
a6401ee0 JB |
21 | (define-module (ice-9 calling)) |
22 | ||
23 | ;;;; | |
24 | ;;; | |
25 | ;;; This file contains a number of macros that support | |
26 | ;;; common calling conventions. | |
27 | ||
28 | ;;; | |
29 | ;;; with-excursion-function <vars> proc | |
30 | ;;; <vars> is an unevaluated list of names that are bound in the caller. | |
31 | ;;; proc is a procedure, called: | |
32 | ;;; (proc excursion) | |
33 | ;;; | |
34 | ;;; excursion is a procedure isolates all changes to <vars> | |
35 | ;;; in the dynamic scope of the call to proc. In other words, | |
36 | ;;; the values of <vars> are saved when proc is entered, and when | |
37 | ;;; proc returns, those values are restored. Values are also restored | |
38 | ;;; entering and leaving the call to proc non-locally, such as using | |
39 | ;;; call-with-current-continuation, error, or throw. | |
40 | ;;; | |
41 | (defmacro-public with-excursion-function (vars proc) | |
42 | `(,proc ,(excursion-function-syntax vars))) | |
43 | ||
44 | ||
45 | ||
46 | ;;; with-getter-and-setter <vars> proc | |
47 | ;;; <vars> is an unevaluated list of names that are bound in the caller. | |
48 | ;;; proc is a procedure, called: | |
49 | ;;; (proc getter setter) | |
50 | ;;; | |
51 | ;;; getter and setter are procedures used to access | |
52 | ;;; or modify <vars>. | |
53 | ;;; | |
54 | ;;; setter, called with keywords arguments, modifies the named | |
55 | ;;; values. If "foo" and "bar" are among <vars>, then: | |
56 | ;;; | |
57 | ;;; (setter :foo 1 :bar 2) | |
58 | ;;; == (set! foo 1 bar 2) | |
59 | ;;; | |
60 | ;;; getter, called with just keywords, returns | |
61 | ;;; a list of the corresponding values. For example, | |
62 | ;;; if "foo" and "bar" are among the <vars>, then | |
63 | ;;; | |
64 | ;;; (getter :foo :bar) | |
65 | ;;; => (<value-of-foo> <value-of-bar>) | |
66 | ;;; | |
67 | ;;; getter, called with no arguments, returns a list of all accepted | |
68 | ;;; keywords and the corresponding values. If "foo" and "bar" are | |
69 | ;;; the *only* <vars>, then: | |
70 | ;;; | |
71 | ;;; (getter) | |
72 | ;;; => (:foo <value-of-bar> :bar <value-of-foo>) | |
73 | ;;; | |
74 | ;;; The unusual calling sequence of a getter supports too handy | |
75 | ;;; idioms: | |
76 | ;;; | |
77 | ;;; (apply setter (getter)) ;; save and restore | |
78 | ;;; | |
79 | ;;; (apply-to-args (getter :foo :bar) ;; fetch and bind | |
80 | ;;; (lambda (foo bar) ....)) | |
81 | ;;; | |
82 | ;;; ;; [ "apply-to-args" is just like two-argument "apply" except that it | |
83 | ;;; ;; takes its arguments in a different order. | |
84 | ;;; | |
85 | ;;; | |
86 | (defmacro-public with-getter-and-setter (vars proc) | |
87 | `(,proc ,@ (getter-and-setter-syntax vars))) | |
88 | ||
89 | ;;; with-getter vars proc | |
90 | ;;; A short-hand for a call to with-getter-and-setter. | |
91 | ;;; The procedure is called: | |
92 | ;;; (proc getter) | |
93 | ;;; | |
94 | (defmacro-public with-getter (vars proc) | |
95 | `(,proc ,(car (getter-and-setter-syntax vars)))) | |
96 | ||
97 | ||
98 | ;;; with-delegating-getter-and-setter <vars> get-delegate set-delegate proc | |
99 | ;;; Compose getters and setters. | |
100 | ;;; | |
101 | ;;; <vars> is an unevaluated list of names that are bound in the caller. | |
102 | ;;; | |
103 | ;;; get-delegate is called by the new getter to extend the set of | |
104 | ;;; gettable variables beyond just <vars> | |
105 | ;;; set-delegate is called by the new setter to extend the set of | |
106 | ;;; gettable variables beyond just <vars> | |
107 | ;;; | |
108 | ;;; proc is a procedure that is called | |
109 | ;;; (proc getter setter) | |
110 | ;;; | |
111 | (defmacro-public with-delegating-getter-and-setter (vars get-delegate set-delegate proc) | |
112 | `(,proc ,@ (delegating-getter-and-setter-syntax vars get-delegate set-delegate))) | |
113 | ||
114 | ||
115 | ;;; with-excursion-getter-and-setter <vars> proc | |
116 | ;;; <vars> is an unevaluated list of names that are bound in the caller. | |
117 | ;;; proc is called: | |
118 | ;;; | |
119 | ;;; (proc excursion getter setter) | |
120 | ;;; | |
121 | ;;; See also: | |
122 | ;;; with-getter-and-setter | |
123 | ;;; with-excursion-function | |
124 | ;;; | |
125 | (defmacro-public with-excursion-getter-and-setter (vars proc) | |
126 | `(,proc ,(excursion-function-syntax vars) | |
127 | ,@ (getter-and-setter-syntax vars))) | |
128 | ||
129 | ||
130 | (define (excursion-function-syntax vars) | |
131 | (let ((saved-value-names (map gensym vars)) | |
132 | (tmp-var-name (gensym 'temp)) | |
133 | (swap-fn-name (gensym 'swap)) | |
134 | (thunk-name (gensym 'thunk))) | |
135 | `(lambda (,thunk-name) | |
63da7567 JB |
136 | (letrec ((,tmp-var-name #f) |
137 | (,swap-fn-name | |
138 | (lambda () ,@ (map (lambda (n sn) | |
139 | `(begin (set! ,tmp-var-name ,n) | |
140 | (set! ,n ,sn) | |
141 | (set! ,sn ,tmp-var-name))) | |
142 | vars saved-value-names))) | |
143 | ,@ (map (lambda (sn n) `(,sn ,n)) saved-value-names vars)) | |
144 | (dynamic-wind | |
145 | ,swap-fn-name | |
146 | ,thunk-name | |
147 | ,swap-fn-name))))) | |
a6401ee0 JB |
148 | |
149 | ||
150 | (define (getter-and-setter-syntax vars) | |
151 | (let ((args-name (gensym 'args)) | |
152 | (an-arg-name (gensym 'an-arg)) | |
153 | (new-val-name (gensym 'new-value)) | |
154 | (loop-name (gensym 'loop)) | |
155 | (kws (map symbol->keyword vars))) | |
156 | (list `(lambda ,args-name | |
157 | (let ,loop-name ((,args-name ,args-name)) | |
158 | (if (null? ,args-name) | |
159 | ,(if (null? kws) | |
160 | ''() | |
161 | `(let ((all-vals (,loop-name ',kws))) | |
162 | (let ,loop-name ((vals all-vals) | |
163 | (kws ',kws)) | |
164 | (if (null? vals) | |
165 | '() | |
166 | `(,(car kws) ,(car vals) ,@(,loop-name (cdr vals) (cdr kws))))))) | |
167 | (map (lambda (,an-arg-name) | |
168 | (case ,an-arg-name | |
169 | ,@ (append | |
170 | (map (lambda (kw v) `((,kw) ,v)) kws vars) | |
171 | `((else (throw 'bad-get-option ,an-arg-name)))))) | |
172 | ,args-name)))) | |
173 | ||
174 | `(lambda ,args-name | |
175 | (let ,loop-name ((,args-name ,args-name)) | |
176 | (or (null? ,args-name) | |
177 | (null? (cdr ,args-name)) | |
178 | (let ((,an-arg-name (car ,args-name)) | |
179 | (,new-val-name (cadr ,args-name))) | |
180 | (case ,an-arg-name | |
181 | ,@ (append | |
182 | (map (lambda (kw v) `((,kw) (set! ,v ,new-val-name))) kws vars) | |
183 | `((else (throw 'bad-set-option ,an-arg-name))))) | |
184 | (,loop-name (cddr ,args-name))))))))) | |
185 | ||
186 | (define (delegating-getter-and-setter-syntax vars get-delegate set-delegate) | |
187 | (let ((args-name (gensym 'args)) | |
188 | (an-arg-name (gensym 'an-arg)) | |
189 | (new-val-name (gensym 'new-value)) | |
190 | (loop-name (gensym 'loop)) | |
191 | (kws (map symbol->keyword vars))) | |
192 | (list `(lambda ,args-name | |
193 | (let ,loop-name ((,args-name ,args-name)) | |
194 | (if (null? ,args-name) | |
195 | (append! | |
196 | ,(if (null? kws) | |
197 | ''() | |
198 | `(let ((all-vals (,loop-name ',kws))) | |
199 | (let ,loop-name ((vals all-vals) | |
200 | (kws ',kws)) | |
201 | (if (null? vals) | |
202 | '() | |
203 | `(,(car kws) ,(car vals) ,@(,loop-name (cdr vals) (cdr kws))))))) | |
204 | (,get-delegate)) | |
205 | (map (lambda (,an-arg-name) | |
206 | (case ,an-arg-name | |
207 | ,@ (append | |
208 | (map (lambda (kw v) `((,kw) ,v)) kws vars) | |
209 | `((else (car (,get-delegate ,an-arg-name))))))) | |
210 | ,args-name)))) | |
211 | ||
212 | `(lambda ,args-name | |
213 | (let ,loop-name ((,args-name ,args-name)) | |
214 | (or (null? ,args-name) | |
215 | (null? (cdr ,args-name)) | |
216 | (let ((,an-arg-name (car ,args-name)) | |
217 | (,new-val-name (cadr ,args-name))) | |
218 | (case ,an-arg-name | |
219 | ,@ (append | |
220 | (map (lambda (kw v) `((,kw) (set! ,v ,new-val-name))) kws vars) | |
221 | `((else (,set-delegate ,an-arg-name ,new-val-name))))) | |
222 | (,loop-name (cddr ,args-name))))))))) | |
223 | ||
224 | ||
225 | ||
226 | ||
227 | ;;; with-configuration-getter-and-setter <vars-etc> proc | |
228 | ;;; | |
229 | ;;; Create a getter and setter that can trigger arbitrary computation. | |
230 | ;;; | |
231 | ;;; <vars-etc> is a list of variable specifiers, explained below. | |
232 | ;;; proc is called: | |
233 | ;;; | |
234 | ;;; (proc getter setter) | |
235 | ;;; | |
236 | ;;; Each element of the <vars-etc> list is of the form: | |
237 | ;;; | |
238 | ;;; (<var> getter-hook setter-hook) | |
239 | ;;; | |
240 | ;;; Both hook elements are evaluated; the variable name is not. | |
241 | ;;; Either hook may be #f or procedure. | |
242 | ;;; | |
243 | ;;; A getter hook is a thunk that returns a value for the corresponding | |
244 | ;;; variable. If omitted (#f is passed), the binding of <var> is | |
245 | ;;; returned. | |
246 | ;;; | |
247 | ;;; A setter hook is a procedure of one argument that accepts a new value | |
248 | ;;; for the corresponding variable. If omitted, the binding of <var> | |
249 | ;;; is simply set using set!. | |
250 | ;;; | |
251 | (defmacro-public with-configuration-getter-and-setter (vars-etc proc) | |
252 | `((lambda (simpler-get simpler-set body-proc) | |
253 | (with-delegating-getter-and-setter () | |
254 | simpler-get simpler-set body-proc)) | |
255 | ||
256 | (lambda (kw) | |
257 | (case kw | |
258 | ,@(map (lambda (v) `((,(symbol->keyword (car v))) | |
259 | ,(cond | |
260 | ((cadr v) => list) | |
261 | (else `(list ,(car v)))))) | |
262 | vars-etc))) | |
263 | ||
264 | (lambda (kw new-val) | |
265 | (case kw | |
266 | ,@(map (lambda (v) `((,(symbol->keyword (car v))) | |
267 | ,(cond | |
268 | ((caddr v) => (lambda (proc) `(,proc new-val))) | |
269 | (else `(set! ,(car v) new-val))))) | |
270 | vars-etc))) | |
271 | ||
272 | ,proc)) | |
273 | ||
274 | (defmacro-public with-delegating-configuration-getter-and-setter (vars-etc delegate-get delegate-set proc) | |
275 | `((lambda (simpler-get simpler-set body-proc) | |
276 | (with-delegating-getter-and-setter () | |
277 | simpler-get simpler-set body-proc)) | |
278 | ||
279 | (lambda (kw) | |
280 | (case kw | |
281 | ,@(append! (map (lambda (v) `((,(symbol->keyword (car v))) | |
282 | ,(cond | |
283 | ((cadr v) => list) | |
284 | (else `(list ,(car v)))))) | |
285 | vars-etc) | |
286 | `((else (,delegate-get kw)))))) | |
287 | ||
288 | (lambda (kw new-val) | |
289 | (case kw | |
290 | ,@(append! (map (lambda (v) `((,(symbol->keyword (car v))) | |
291 | ,(cond | |
292 | ((caddr v) => (lambda (proc) `(,proc new-val))) | |
293 | (else `(set! ,(car v) new-val))))) | |
294 | vars-etc) | |
295 | `((else (,delegate-set kw new-val)))))) | |
296 | ||
297 | ,proc)) | |
298 | ||
299 | ||
300 | ;;; let-configuration-getter-and-setter <vars-etc> proc | |
301 | ;;; | |
302 | ;;; This procedure is like with-configuration-getter-and-setter (q.v.) | |
303 | ;;; except that each element of <vars-etc> is: | |
304 | ;;; | |
305 | ;;; (<var> initial-value getter-hook setter-hook) | |
306 | ;;; | |
307 | ;;; Unlike with-configuration-getter-and-setter, let-configuration-getter-and-setter | |
308 | ;;; introduces bindings for the variables named in <vars-etc>. | |
309 | ;;; It is short-hand for: | |
310 | ;;; | |
311 | ;;; (let ((<var1> initial-value-1) | |
312 | ;;; (<var2> initial-value-2) | |
313 | ;;; ...) | |
314 | ;;; (with-configuration-getter-and-setter ((<var1> v1-get v1-set) ...) proc)) | |
315 | ;;; | |
316 | (defmacro-public let-with-configuration-getter-and-setter (vars-etc proc) | |
317 | `(let ,(map (lambda (v) `(,(car v) ,(cadr v))) vars-etc) | |
318 | (with-configuration-getter-and-setter ,(map (lambda (v) `(,(car v) ,(caddr v) ,(cadddr v))) vars-etc) | |
319 | ,proc))) | |
320 | ||
321 | ||
322 |