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<h1 class='fqn'><span class='in-band'>Macro <a href='index.html'>synom</a>::<wbr><a class="macro" href=''>tag</a></span><span class='out-of-band'><span id='render-detail'>
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[<span class='inner'>−</span>]
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</span><a class='srclink' href='../src/synom/lib.rs.html#732-740' 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">tag</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">tag</span>:<span class="ident">expr</span>) <span class="op">=></span> { ... };
}</pre>
<div class='docblock'><p>Parse the given string from exactly the current position in the input. You
almost always want <code>punct!</code> or <code>keyword!</code> instead of this.</p>
<p>The <code>tag!</code> parser is equivalent to <code>punct!</code> but does not ignore leading
whitespace. Both <code>punct!</code> and <code>keyword!</code> skip over leading whitespace. See
an explanation of synom's whitespace handling strategy in the top-level
crate documentation.</p>
<ul>
<li><strong>Syntax:</strong> <code>tag!("...")</code></li>
<li><strong>Output:</strong> <code>"..."</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">StrLit</span>;
<span class="kw">use</span> <span class="ident">syn</span>::<span class="ident">parse</span>::<span class="ident">string</span>;
<span class="kw">use</span> <span class="ident">synom</span>::<span class="ident">IResult</span>;
<span class="comment">// Parse a proposed syntax for an owned string literal: "abc"s</span>
<span class="macro">named</span><span class="macro">!</span>(<span class="ident">owned_string</span> <span class="op">-></span> <span class="ident">String</span>,
<span class="macro">map</span><span class="macro">!</span>(
<span class="macro">terminated</span><span class="macro">!</span>(<span class="ident">string</span>, <span class="macro">tag</span><span class="macro">!</span>(<span class="string">"s"</span>)),
<span class="op">|</span><span class="ident">lit</span>: <span class="ident">StrLit</span><span class="op">|</span> <span class="ident">lit</span>.<span class="ident">value</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">r#" "abc"s "#</span>;
<span class="kw">let</span> <span class="ident">parsed</span> <span class="op">=</span> <span class="ident">owned_string</span>(<span class="ident">input</span>).<span class="ident">expect</span>(<span class="string">"owned string literal"</span>);
<span class="macro">println</span><span class="macro">!</span>(<span class="string">"{:?}"</span>, <span class="ident">parsed</span>);
<span class="kw">let</span> <span class="ident">input</span> <span class="op">=</span> <span class="string">r#" "abc" s "#</span>;
<span class="kw">let</span> <span class="ident">err</span> <span class="op">=</span> <span class="ident">owned_string</span>(<span class="ident">input</span>);
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">err</span>, <span class="ident">IResult</span>::<span class="ident">Error</span>);
}</pre>
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