191 lines
7.7 KiB
Plaintext
Generated
191 lines
7.7 KiB
Plaintext
Generated
<!DOCTYPE html>
|
|
<html>
|
|
<head>
|
|
<meta charset="utf-8">
|
|
<title>Go by Example: Channel Directions</title>
|
|
<link rel=stylesheet href="site.css">
|
|
</head>
|
|
<script>
|
|
onkeydown = (e) => {
|
|
|
|
if (e.key == "ArrowLeft") {
|
|
window.location.href = 'channel-synchronization';
|
|
}
|
|
|
|
|
|
if (e.key == "ArrowRight") {
|
|
window.location.href = 'select';
|
|
}
|
|
|
|
}
|
|
</script>
|
|
<body>
|
|
<div class="example" id="channel-directions">
|
|
<h2><a href="./">Go by Example</a>: Channel Directions</h2>
|
|
|
|
<table>
|
|
|
|
<tr>
|
|
<td class="docs">
|
|
<p>When using channels as function parameters, you can
|
|
specify if a channel is meant to only send or receive
|
|
values. This specificity increases the type-safety of
|
|
the program.</p>
|
|
|
|
</td>
|
|
<td class="code empty leading">
|
|
|
|
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td class="docs">
|
|
|
|
</td>
|
|
<td class="code leading">
|
|
<a href="https://go.dev/play/p/mjNJDHwUH4R"><img title="Run code" src="play.png" class="run" /></a><img title="Copy code" src="clipboard.png" class="copy" />
|
|
<pre class="chroma"><span class="kn">package</span> <span class="nx">main</span>
|
|
</pre>
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td class="docs">
|
|
|
|
</td>
|
|
<td class="code leading">
|
|
|
|
<pre class="chroma"><span class="kn">import</span> <span class="s">"fmt"</span>
|
|
</pre>
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td class="docs">
|
|
<p>This <code>ping</code> function only accepts a channel for sending
|
|
values. It would be a compile-time error to try to
|
|
receive on this channel.</p>
|
|
|
|
</td>
|
|
<td class="code leading">
|
|
|
|
<pre class="chroma">
|
|
<span class="kd">func</span> <span class="nf">ping</span><span class="p">(</span><span class="nx">pings</span> <span class="kd">chan</span><span class="o"><-</span> <span class="kt">string</span><span class="p">,</span> <span class="nx">msg</span> <span class="kt">string</span><span class="p">)</span> <span class="p">{</span>
|
|
<span class="nx">pings</span> <span class="o"><-</span> <span class="nx">msg</span>
|
|
<span class="p">}</span>
|
|
</pre>
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td class="docs">
|
|
<p>The <code>pong</code> function accepts one channel for receives
|
|
(<code>pings</code>) and a second for sends (<code>pongs</code>).</p>
|
|
|
|
</td>
|
|
<td class="code leading">
|
|
|
|
<pre class="chroma">
|
|
<span class="kd">func</span> <span class="nf">pong</span><span class="p">(</span><span class="nx">pings</span> <span class="o"><-</span><span class="kd">chan</span> <span class="kt">string</span><span class="p">,</span> <span class="nx">pongs</span> <span class="kd">chan</span><span class="o"><-</span> <span class="kt">string</span><span class="p">)</span> <span class="p">{</span>
|
|
<span class="nx">msg</span> <span class="o">:=</span> <span class="o"><-</span><span class="nx">pings</span>
|
|
<span class="nx">pongs</span> <span class="o"><-</span> <span class="nx">msg</span>
|
|
<span class="p">}</span>
|
|
</pre>
|
|
</td>
|
|
</tr>
|
|
|
|
<tr>
|
|
<td class="docs">
|
|
|
|
</td>
|
|
<td class="code">
|
|
|
|
<pre class="chroma"><span class="kd">func</span> <span class="nf">main</span><span class="p">()</span> <span class="p">{</span>
|
|
<span class="nx">pings</span> <span class="o">:=</span> <span class="nb">make</span><span class="p">(</span><span class="kd">chan</span> <span class="kt">string</span><span class="p">,</span> <span class="mi">1</span><span class="p">)</span>
|
|
<span class="nx">pongs</span> <span class="o">:=</span> <span class="nb">make</span><span class="p">(</span><span class="kd">chan</span> <span class="kt">string</span><span class="p">,</span> <span class="mi">1</span><span class="p">)</span>
|
|
<span class="nf">ping</span><span class="p">(</span><span class="nx">pings</span><span class="p">,</span> <span class="s">"passed message"</span><span class="p">)</span>
|
|
<span class="nf">pong</span><span class="p">(</span><span class="nx">pings</span><span class="p">,</span> <span class="nx">pongs</span><span class="p">)</span>
|
|
<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="o"><-</span><span class="nx">pongs</span><span class="p">)</span>
|
|
<span class="p">}</span>
|
|
</pre>
|
|
</td>
|
|
</tr>
|
|
|
|
</table>
|
|
|
|
<table>
|
|
|
|
<tr>
|
|
<td class="docs">
|
|
|
|
</td>
|
|
<td class="code">
|
|
|
|
<pre class="chroma"><span class="gp">$</span> go run channel-directions.go
|
|
<span class="go">passed message</span></pre>
|
|
</td>
|
|
</tr>
|
|
|
|
</table>
|
|
|
|
|
|
<p class="next">
|
|
Next example: <a href="select">Select</a>.
|
|
</p>
|
|
|
|
|
|
<p class="footer">
|
|
<script>
|
|
window.onload = function() {
|
|
function styleAllTags(tag, style, value){
|
|
document.querySelectorAll(tag).forEach((tag) => {
|
|
tag.style[style] = value
|
|
})
|
|
}
|
|
|
|
var themeButton = document.getElementById('theme-button');
|
|
var body = document.getElementsByTagName('body')[0];
|
|
|
|
function activateTheme(theme) {
|
|
if (theme === 'dark') {
|
|
body.style.color = "#ffffffeb";
|
|
body.style.backgroundColor = "#1a202c";
|
|
styleAllTags('a', 'color', '#ffffffeb')
|
|
styleAllTags('td.code', 'background', '#333333')
|
|
styleAllTags('td.code.empty', 'background', '#1a202c')
|
|
} else {
|
|
body.style.color = "#252519";
|
|
body.style.backgroundColor = "white";
|
|
styleAllTags('a', 'color', '#252519')
|
|
styleAllTags('td.code', 'background', '#f0f0f0')
|
|
styleAllTags('td.code.empty', 'background', 'white')
|
|
}
|
|
localStorage.setItem('theme', theme);
|
|
}
|
|
|
|
var currentTheme = localStorage.getItem('theme');
|
|
if (currentTheme === 'light' || currentTheme === 'dark') {
|
|
activateTheme(currentTheme);
|
|
} else {
|
|
activateTheme('light');
|
|
}
|
|
|
|
themeButton.onclick = function() {
|
|
var newTheme = localStorage.getItem('theme') === 'dark' ? 'light' : 'dark';
|
|
activateTheme(newTheme);
|
|
}
|
|
}
|
|
</script>
|
|
by <a href="https://markmcgranaghan.com">Mark McGranaghan</a> and <a href="https://eli.thegreenplace.net">Eli Bendersky</a> | <a href="https://github.com/mmcgrana/gobyexample">source</a> | <a href="https://github.com/mmcgrana/gobyexample#license">license</a> | <button id="theme-button">Toggle theme</button>
|
|
</p>
|
|
|
|
</div>
|
|
<script>
|
|
var codeLines = [];
|
|
codeLines.push('');codeLines.push('package main\u000A');codeLines.push('import \"fmt\"\u000A');codeLines.push('func ping(pings chan\u003C- string, msg string) {\u000A pings \u003C- msg\u000A}\u000A');codeLines.push('func pong(pings \u003C-chan string, pongs chan\u003C- string) {\u000A msg :\u003D \u003C-pings\u000A pongs \u003C- msg\u000A}\u000A');codeLines.push('func main() {\u000A pings :\u003D make(chan string, 1)\u000A pongs :\u003D make(chan string, 1)\u000A ping(pings, \"passed message\")\u000A pong(pings, pongs)\u000A fmt.Println(\u003C-pongs)\u000A}\u000A');codeLines.push('');
|
|
</script>
|
|
<script src="site.js" async></script>
|
|
</body>
|
|
</html>
|