1;;;
2;;; srfi-190 - Coroutine generator
3;;;
4;;;   Copyright (c) 2020  Shiro Kawai  <shiro@acm.org>
5;;;
6;;;   Redistribution and use in source and binary forms, with or without
7;;;   modification, are permitted provided that the following conditions
8;;;   are met:
9;;;
10;;;   1. Redistributions of source code must retain the above copyright
11;;;      notice, this list of conditions and the following disclaimer.
12;;;
13;;;   2. Redistributions in binary form must reproduce the above copyright
14;;;      notice, this list of conditions and the following disclaimer in the
15;;;      documentation and/or other materials provided with the distribution.
16;;;
17;;;   3. Neither the name of the authors nor the names of its contributors
18;;;      may be used to endorse or promote products derived from this
19;;;      software without specific prior written permission.
20;;;
21;;;   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22;;;   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23;;;   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
24;;;   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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32;;;
33
34;; EXPERIMENTAL - not using identifier syntax
35;; NB: This isn't correct.  See the mail archive of srfi-190.
36
37(define-module srfi-190
38  (use gauche.generator)
39  (export coroutine-generator yield define-coroutine-generator))
40(select-module srfi-190)
41
42(define yield-proc
43  (make-parameter (^_ (error "yield used outside coroutine generator"))))
44
45(define (yield x) ((yield-proc) x))
46
47(define-syntax coroutine-generator
48  (syntax-rules ()
49    [(_ . body)
50     (make-coroutine-generator
51      (^[%yield]
52       (parameterize ((yield-proc %yield))
53         . body)))]))
54
55(define-syntax define-coroutine-generator
56  (syntax-rules ()
57    [(_ name . body) (define name (coroutine-generator . body))]))
58