blob: 24c3dba0c21fe670e3cd79de93d93193f5e77211 (
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
|
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<!-- Copyright (C) 2017-2021 David Thompson davet@gnu.org
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3
or any later version published by the Free Software Foundation;
with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
A copy of the license is included in the section entitled "GNU
Free Documentation License".
A copy of the license is also available from the Free Software
Foundation Web site at http://www.gnu.org/licenses/fdl.html.
* Chickadee: (chickadee). Game programming toolkit for Guile.
The document was typeset with
http://www.texinfo.org/ (GNU Texinfo).
-->
<!-- Created by GNU Texinfo 6.7, http://www.gnu.org/software/texinfo/ -->
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Channels (The Chickadee Game Toolkit)</title>
<meta name="description" content="Channels (The Chickadee Game Toolkit)">
<meta name="keywords" content="Channels (The Chickadee Game Toolkit)">
<meta name="resource-type" content="document">
<meta name="distribution" content="global">
<meta name="Generator" content="makeinfo">
<link href="index.html" rel="start" title="Top">
<link href="Index.html" rel="index" title="Index">
<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
<link href="Scripting.html" rel="up" title="Scripting">
<link href="Data-Structures.html" rel="next" title="Data Structures">
<link href="Tweening.html" rel="prev" title="Tweening">
<style type="text/css">
<!--
a.summary-letter {text-decoration: none}
blockquote.indentedblock {margin-right: 0em}
div.display {margin-left: 3.2em}
div.example {margin-left: 3.2em}
div.lisp {margin-left: 3.2em}
kbd {font-style: oblique}
pre.display {font-family: inherit}
pre.format {font-family: inherit}
pre.menu-comment {font-family: serif}
pre.menu-preformatted {font-family: serif}
span.nolinebreak {white-space: nowrap}
span.roman {font-family: initial; font-weight: normal}
span.sansserif {font-family: sans-serif; font-weight: normal}
ul.no-bullet {list-style: none}
@media (min-width: 1140px) {
body {
margin-left: 14rem;
margin-right: 4rem;
max-width: 52rem;
}
}
@media (min-width: 800px) and (max-width: 1140px) {
body {
margin-left: 6rem;
margin-right: 4rem;
max-width: 52rem;
}
}
@media (max-width: 800px) {
body {
margin: 1rem;
}
}
-->
</style>
<link rel="stylesheet" type="text/css" href="https://dthompson.us/css/dthompson.css">
</head>
<body lang="en">
<span id="Channels"></span><div class="header">
<p>
Previous: <a href="Tweening.html" accesskey="p" rel="prev">Tweening</a>, Up: <a href="Scripting.html" accesskey="u" rel="up">Scripting</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html" title="Index" rel="index">Index</a>]</p>
</div>
<hr>
<span id="Channels-1"></span><h4 class="subsection">5.5.4 Channels</h4>
<p>Channels are a tool for communicating amongst different scripts. One
script can write a value to the channel and another can read from it.
Reading or writing to a channel suspends that script until there is
someone on the other end of the line to complete the transaction.
</p>
<p>Here’s a simplistic example:
</p>
<div class="example">
<pre class="example">(define c (make-channel))
(script
(forever
(let ((item (channel-get c)))
(pk 'got item))))
(script
(channel-put c 'sword)
(channel-put c 'shield)
(channel-put c 'potion))
</pre></div>
<dl>
<dt id="index-make_002dchannel">Procedure: <strong>make-channel</strong></dt>
<dd><p>Return a new channel
</p></dd></dl>
<dl>
<dt id="index-channel_003f">Procedure: <strong>channel?</strong> <em>obj</em></dt>
<dd><p>Return <code>#t</code> if <var>obj</var> is a channel.
</p></dd></dl>
<dl>
<dt id="index-channel_002dget">Procedure: <strong>channel-get</strong> <em>channel</em></dt>
<dd><p>Retrieve a value from <var>channel</var>. The current script suspends
until a value is available.
</p></dd></dl>
<dl>
<dt id="index-channel_002dput">Procedure: <strong>channel-put</strong> <em>channel data</em></dt>
<dd><p>Send <var>data</var> to <var>channel</var>. The current script suspends until
another script is available to retrieve the value.
</p></dd></dl>
<p>A low-level API also exists for using channels outside of a script via
callback procedures:
</p>
<dl>
<dt id="index-channel_002dget_0021">Procedure: <strong>channel-get!</strong> <em>channel proc</em></dt>
<dd><p>Asynchronously retrieve a value from <var>channel</var> and call <var>proc</var>
with that value.
</p></dd></dl>
<dl>
<dt id="index-channel_002dput_0021">Procedure: <strong>channel-put!</strong> <em>channel data [thunk]</em></dt>
<dd><p>Asynchronously send <var>data</var> to <var>channel</var> and call <var>thunk</var>
after it has been received.
</p></dd></dl>
<dl>
<dt id="index-channel_002dclear_0021">Procedure: <strong>channel-clear!</strong> <em>channel</em></dt>
<dd><p>Clear all messages and scripts awaiting messages in <var>channel</var>.
</p></dd></dl>
</body>
</html>
|
