RONCC
/
HPC-Tools-for-Quantum-Computing


			
				
					
						
						
							123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170
							<!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 `alt` macro in crate `synom`.">
    <meta name="keywords" content="rust, rustlang, rust-lang, alt">

    <title>synom::alt - Rust</title>

    <link rel="stylesheet" type="text/css" href="../normalize.css">
    <link rel="stylesheet" type="text/css" href="../rustdoc.css" id="mainThemeStyle">
    
    <link rel="stylesheet" type="text/css" href="../dark.css">
    <link rel="stylesheet" type="text/css" href="../main.css" id="themeStyle">
    <script src="../storage.js"></script>
    

    
    
</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">
        <div class="sidebar-menu">&#9776;</div>
        
        <p class='location'><a href='index.html'>synom</a></p><script>window.sidebarCurrent = {name: 'alt', ty: 'macro', relpath: ''};</script><script defer src="sidebar-items.js"></script>
    </nav>

    <div class="theme-picker">
        <button id="theme-picker" aria-label="Pick another theme!">
            <img src="../brush.svg" width="18" alt="Pick another theme!">
        </button>
        <div id="theme-choices"></div>
    </div>
    <script src="../theme.js"></script>
    <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=''>alt</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'>&#x2212;</span>]
                   </a>
               </span><a class='srclink' href='../src/synom/lib.rs.html#1106-1147' 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">alt</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">e</span>:<span class="ident">ident</span> <span class="op">|</span> $(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">rest</span>:<span class="ident">tt</span>)<span class="kw-2">*</span>) <span class="op">=&gt;</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">subrule</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="kw-2">*</span>) <span class="op">|</span> $(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">rest</span>:<span class="ident">tt</span>)<span class="kw-2">*</span>) <span class="op">=&gt;</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">subrule</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">=&gt;</span> { <span class="macro-nonterminal">$</span><span class="macro-nonterminal">gen</span>:<span class="ident">expr</span> } <span class="op">|</span> $(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">rest</span>:<span class="ident">tt</span>)<span class="op">+</span>) <span class="op">=&gt;</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">e</span>:<span class="ident">ident</span> <span class="op">=&gt;</span> { <span class="macro-nonterminal">$</span><span class="macro-nonterminal">gen</span>:<span class="ident">expr</span> } <span class="op">|</span> $(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">rest</span>:<span class="ident">tt</span>)<span class="kw-2">*</span>) <span class="op">=&gt;</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">e</span>:<span class="ident">ident</span> <span class="op">=&gt;</span> { <span class="macro-nonterminal">$</span><span class="macro-nonterminal">gen</span>:<span class="ident">expr</span> }) <span class="op">=&gt;</span> { ... };
    (<span class="macro-nonterminal">$</span><span class="macro-nonterminal">i</span>:<span class="ident">expr</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">subrule</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">=&gt;</span> { <span class="macro-nonterminal">$</span><span class="macro-nonterminal">gen</span>:<span class="ident">expr</span> }) <span class="op">=&gt;</span> { ... };
    (<span class="macro-nonterminal">$</span><span class="macro-nonterminal">i</span>:<span class="ident">expr</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">e</span>:<span class="ident">ident</span>) <span class="op">=&gt;</span> { ... };
    (<span class="macro-nonterminal">$</span><span class="macro-nonterminal">i</span>:<span class="ident">expr</span>, <span class="macro-nonterminal">$</span><span class="macro-nonterminal">subrule</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="kw-2">*</span>)) <span class="op">=&gt;</span> { ... };
}</pre>
<div class='docblock'><p>Run a series of parsers, returning the result of the first one which
succeeds.</p>
<p>Optionally allows for the result to be transformed.</p>
<ul>
<li><strong>Syntax:</strong> <code>alt!(THING1 | THING2 =&gt; { FUNC } | ...)</code></li>
<li><strong>Output:</strong> <code>T</code>, the return type of <code>THING1</code> and <code>FUNC(THING2)</code> and ...</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">Ident</span>;
<span class="kw">use</span> <span class="ident">syn</span>::<span class="ident">parse</span>::<span class="ident">ident</span>;

<span class="macro">named</span><span class="macro">!</span>(<span class="ident">ident_or_bang</span> <span class="op">-&gt;</span> <span class="ident">Ident</span>,
    <span class="macro">alt</span><span class="macro">!</span>(
        <span class="ident">ident</span>
        <span class="op">|</span>
        <span class="macro">punct</span><span class="macro">!</span>(<span class="string">&quot;!&quot;</span>) <span class="op">=&gt;</span> { <span class="op">|</span>_<span class="op">|</span> <span class="string">&quot;BANG&quot;</span>.<span class="ident">into</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">&quot;foo&quot;</span>;
    <span class="kw">let</span> <span class="ident">parsed</span> <span class="op">=</span> <span class="ident">ident_or_bang</span>(<span class="ident">input</span>).<span class="ident">expect</span>(<span class="string">&quot;identifier or `!`&quot;</span>);
    <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">parsed</span>, <span class="string">&quot;foo&quot;</span>);

    <span class="kw">let</span> <span class="ident">input</span> <span class="op">=</span> <span class="string">&quot;!&quot;</span>;
    <span class="kw">let</span> <span class="ident">parsed</span> <span class="op">=</span> <span class="ident">ident_or_bang</span>(<span class="ident">input</span>).<span class="ident">expect</span>(<span class="string">&quot;identifier or `!`&quot;</span>);
    <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">parsed</span>, <span class="string">&quot;BANG&quot;</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><kbd>?</kbd></dt>
                    <dd>Show this help dialog</dd>
                    <dt><kbd>S</kbd></dt>
                    <dd>Focus the search field</dd>
                    <dt><kbd>↑</kbd></dt>
                    <dd>Move up in search results</dd>
                    <dt><kbd>↓</kbd></dt>
                    <dd>Move down in search results</dd>
                    <dt><kbd>↹</kbd></dt>
                    <dd>Switch tab</dd>
                    <dt><kbd>&#9166;</kbd></dt>
                    <dd>Go to active search result</dd>
                    <dt><kbd>+</kbd></dt>
                    <dd>Expand all sections</dd>
                    <dt><kbd>-</kbd></dt>
                    <dd>Collapse 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>