177 lines
13 KiB
HTML
177 lines
13 KiB
HTML
<!DOCTYPE html>
|
||
<html lang="en">
|
||
<head>
|
||
<meta charset="utf-8">
|
||
<meta name="viewport" content="width=device-width, initial-scale=1.0">
|
||
<meta name="generator" content="rustdoc">
|
||
<meta name="description" content="API documentation for the Rust `cond` macro in crate `synom`.">
|
||
<meta name="keywords" content="rust, rustlang, rust-lang, cond">
|
||
|
||
<title>synom::cond - Rust</title>
|
||
|
||
<link rel="stylesheet" type="text/css" href="../normalize.css">
|
||
<link rel="stylesheet" type="text/css" href="../rustdoc.css">
|
||
<link rel="stylesheet" type="text/css" href="../main.css">
|
||
|
||
|
||
|
||
|
||
</head>
|
||
<body class="rustdoc macro">
|
||
<!--[if lte IE 8]>
|
||
<div class="warning">
|
||
This old browser is unsupported and will most likely display funky
|
||
things.
|
||
</div>
|
||
<![endif]-->
|
||
|
||
|
||
|
||
<nav class="sidebar">
|
||
|
||
<p class='location'><a href='index.html'>synom</a></p><script>window.sidebarCurrent = {name: 'cond', ty: 'macro', relpath: ''};</script><script defer src="sidebar-items.js"></script>
|
||
</nav>
|
||
|
||
<nav class="sub">
|
||
<form class="search-form js-only">
|
||
<div class="search-container">
|
||
<input class="search-input" name="search"
|
||
autocomplete="off"
|
||
placeholder="Click or press ‘S’ to search, ‘?’ for more options…"
|
||
type="search">
|
||
</div>
|
||
</form>
|
||
</nav>
|
||
|
||
<section id='main' class="content">
|
||
<h1 class='fqn'><span class='in-band'>Macro <a href='index.html'>synom</a>::<wbr><a class="macro" href=''>cond</a></span><span class='out-of-band'><span id='render-detail'>
|
||
<a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs">
|
||
[<span class='inner'>−</span>]
|
||
</a>
|
||
</span><a class='srclink' href='../src/synom/lib.rs.html#307-322' title='goto source code'>[src]</a></span></h1>
|
||
<pre class="rust macro">
|
||
<span class="macro">macro_rules</span><span class="macro">!</span> <span class="ident">cond</span> {
|
||
(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">i</span>:<span class="ident">expr</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">cond</span>:<span class="ident">expr</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">submac</span>:<span class="macro">ident</span><span class="macro">!</span>( $(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">args</span>:<span class="ident">tt</span>)<span class="op">*</span> )) <span class="op">=></span> { ... };
|
||
(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">i</span>:<span class="ident">expr</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">cond</span>:<span class="ident">expr</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">f</span>:<span class="ident">expr</span>) <span class="op">=></span> { ... };
|
||
}</pre>
|
||
<div class='docblock'><p>Conditionally execute the given parser.</p>
|
||
|
||
<p>If you are familiar with nom, this is nom's <code>cond_with_error</code> parser.</p>
|
||
|
||
<ul>
|
||
<li><strong>Syntax:</strong> <code>cond!(CONDITION, THING)</code></li>
|
||
<li><strong>Output:</strong> <code>Some(THING)</code> if the condition is true, else <code>None</code></li>
|
||
</ul>
|
||
|
||
<pre class="rust rust-example-rendered">
|
||
<span class="kw">extern</span> <span class="kw">crate</span> <span class="ident">syn</span>;
|
||
<span class="attribute">#[<span class="ident">macro_use</span>]</span> <span class="kw">extern</span> <span class="kw">crate</span> <span class="ident">synom</span>;
|
||
|
||
<span class="kw">use</span> <span class="ident">syn</span>::<span class="ident">parse</span>::<span class="ident">boolean</span>;
|
||
|
||
<span class="comment">// Parses a tuple of booleans like `(true, false, false)`, possibly with a</span>
|
||
<span class="comment">// dotdot indicating omitted values like `(true, true, .., true)`. Returns</span>
|
||
<span class="comment">// separate vectors for the booleans before and after the dotdot. The second</span>
|
||
<span class="comment">// vector is None if there was no dotdot.</span>
|
||
<span class="macro">named</span><span class="macro">!</span>(<span class="ident">bools_with_dotdot</span> <span class="op">-></span> (<span class="ident">Vec</span><span class="op"><</span><span class="ident">bool</span><span class="op">></span>, <span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">Vec</span><span class="op"><</span><span class="ident">bool</span><span class="op">>></span>), <span class="macro">do_parse</span><span class="macro">!</span>(
|
||
<span class="macro">punct</span><span class="macro">!</span>(<span class="string">"("</span>) <span class="op">>></span>
|
||
<span class="ident">before</span>: <span class="macro">separated_list</span><span class="macro">!</span>(<span class="macro">punct</span><span class="macro">!</span>(<span class="string">","</span>), <span class="ident">boolean</span>) <span class="op">>></span>
|
||
<span class="ident">after</span>: <span class="macro">option</span><span class="macro">!</span>(<span class="macro">do_parse</span><span class="macro">!</span>(
|
||
<span class="comment">// Only allow comma if there are elements before dotdot, i.e. cannot</span>
|
||
<span class="comment">// be `(, .., true)`.</span>
|
||
<span class="macro">cond</span><span class="macro">!</span>(<span class="op">!</span><span class="ident">before</span>.<span class="ident">is_empty</span>(), <span class="macro">punct</span><span class="macro">!</span>(<span class="string">","</span>)) <span class="op">>></span>
|
||
<span class="macro">punct</span><span class="macro">!</span>(<span class="string">".."</span>) <span class="op">>></span>
|
||
<span class="ident">after</span>: <span class="macro">many0</span><span class="macro">!</span>(<span class="macro">preceded</span><span class="macro">!</span>(<span class="macro">punct</span><span class="macro">!</span>(<span class="string">","</span>), <span class="ident">boolean</span>)) <span class="op">>></span>
|
||
<span class="comment">// Only allow trailing comma if there are elements after dotdot,</span>
|
||
<span class="comment">// i.e. cannot be `(true, .., )`.</span>
|
||
<span class="macro">cond</span><span class="macro">!</span>(<span class="op">!</span><span class="ident">after</span>.<span class="ident">is_empty</span>(), <span class="macro">option</span><span class="macro">!</span>(<span class="macro">punct</span><span class="macro">!</span>(<span class="string">","</span>))) <span class="op">>></span>
|
||
(<span class="ident">after</span>)
|
||
)) <span class="op">>></span>
|
||
<span class="comment">// Allow trailing comma if there is no dotdot but there are elements.</span>
|
||
<span class="macro">cond</span><span class="macro">!</span>(<span class="op">!</span><span class="ident">before</span>.<span class="ident">is_empty</span>() <span class="op">&&</span> <span class="ident">after</span>.<span class="ident">is_none</span>(), <span class="macro">option</span><span class="macro">!</span>(<span class="macro">punct</span><span class="macro">!</span>(<span class="string">","</span>))) <span class="op">>></span>
|
||
<span class="macro">punct</span><span class="macro">!</span>(<span class="string">")"</span>) <span class="op">>></span>
|
||
(<span class="ident">before</span>, <span class="ident">after</span>)
|
||
));
|
||
|
||
<span class="kw">fn</span> <span class="ident">main</span>() {
|
||
<span class="kw">let</span> <span class="ident">input</span> <span class="op">=</span> <span class="string">"(true, false, false)"</span>;
|
||
<span class="kw">let</span> <span class="ident">parsed</span> <span class="op">=</span> <span class="ident">bools_with_dotdot</span>(<span class="ident">input</span>).<span class="ident">expect</span>(<span class="string">"bools with dotdot"</span>);
|
||
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">parsed</span>, (<span class="macro">vec</span><span class="macro">!</span>[<span class="bool-val">true</span>, <span class="bool-val">false</span>, <span class="bool-val">false</span>], <span class="prelude-val">None</span>));
|
||
|
||
<span class="kw">let</span> <span class="ident">input</span> <span class="op">=</span> <span class="string">"(true, true, .., true)"</span>;
|
||
<span class="kw">let</span> <span class="ident">parsed</span> <span class="op">=</span> <span class="ident">bools_with_dotdot</span>(<span class="ident">input</span>).<span class="ident">expect</span>(<span class="string">"bools with dotdot"</span>);
|
||
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">parsed</span>, (<span class="macro">vec</span><span class="macro">!</span>[<span class="bool-val">true</span>, <span class="bool-val">true</span>], <span class="prelude-val">Some</span>(<span class="macro">vec</span><span class="macro">!</span>[<span class="bool-val">true</span>])));
|
||
|
||
<span class="kw">let</span> <span class="ident">input</span> <span class="op">=</span> <span class="string">"(.., true)"</span>;
|
||
<span class="kw">let</span> <span class="ident">parsed</span> <span class="op">=</span> <span class="ident">bools_with_dotdot</span>(<span class="ident">input</span>).<span class="ident">expect</span>(<span class="string">"bools with dotdot"</span>);
|
||
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">parsed</span>, (<span class="macro">vec</span><span class="macro">!</span>[], <span class="prelude-val">Some</span>(<span class="macro">vec</span><span class="macro">!</span>[<span class="bool-val">true</span>])));
|
||
|
||
<span class="kw">let</span> <span class="ident">input</span> <span class="op">=</span> <span class="string">"(true, true, ..)"</span>;
|
||
<span class="kw">let</span> <span class="ident">parsed</span> <span class="op">=</span> <span class="ident">bools_with_dotdot</span>(<span class="ident">input</span>).<span class="ident">expect</span>(<span class="string">"bools with dotdot"</span>);
|
||
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">parsed</span>, (<span class="macro">vec</span><span class="macro">!</span>[<span class="bool-val">true</span>, <span class="bool-val">true</span>], <span class="prelude-val">Some</span>(<span class="macro">vec</span><span class="macro">!</span>[])));
|
||
|
||
<span class="kw">let</span> <span class="ident">input</span> <span class="op">=</span> <span class="string">"(..)"</span>;
|
||
<span class="kw">let</span> <span class="ident">parsed</span> <span class="op">=</span> <span class="ident">bools_with_dotdot</span>(<span class="ident">input</span>).<span class="ident">expect</span>(<span class="string">"bools with dotdot"</span>);
|
||
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">parsed</span>, (<span class="macro">vec</span><span class="macro">!</span>[], <span class="prelude-val">Some</span>(<span class="macro">vec</span><span class="macro">!</span>[])));
|
||
}</pre>
|
||
</div></section>
|
||
<section id='search' class="content hidden"></section>
|
||
|
||
<section class="footer"></section>
|
||
|
||
<aside id="help" class="hidden">
|
||
<div>
|
||
<h1 class="hidden">Help</h1>
|
||
|
||
<div class="shortcuts">
|
||
<h2>Keyboard Shortcuts</h2>
|
||
|
||
<dl>
|
||
<dt>?</dt>
|
||
<dd>Show this help dialog</dd>
|
||
<dt>S</dt>
|
||
<dd>Focus the search field</dd>
|
||
<dt>⇤</dt>
|
||
<dd>Move up in search results</dd>
|
||
<dt>⇥</dt>
|
||
<dd>Move down in search results</dd>
|
||
<dt>⏎</dt>
|
||
<dd>Go to active search result</dd>
|
||
<dt>+</dt>
|
||
<dd>Collapse/expand all sections</dd>
|
||
</dl>
|
||
</div>
|
||
|
||
<div class="infos">
|
||
<h2>Search Tricks</h2>
|
||
|
||
<p>
|
||
Prefix searches with a type followed by a colon (e.g.
|
||
<code>fn:</code>) to restrict the search to a given type.
|
||
</p>
|
||
|
||
<p>
|
||
Accepted types are: <code>fn</code>, <code>mod</code>,
|
||
<code>struct</code>, <code>enum</code>,
|
||
<code>trait</code>, <code>type</code>, <code>macro</code>,
|
||
and <code>const</code>.
|
||
</p>
|
||
|
||
<p>
|
||
Search functions by type signature (e.g.
|
||
<code>vec -> usize</code> or <code>* -> vec</code>)
|
||
</p>
|
||
</div>
|
||
</div>
|
||
</aside>
|
||
|
||
|
||
|
||
<script>
|
||
window.rootPath = "../";
|
||
window.currentCrate = "synom";
|
||
</script>
|
||
<script src="../main.js"></script>
|
||
<script defer src="../search-index.js"></script>
|
||
</body>
|
||
</html> |