github-actions[bot]
116 lines
14 KiB
HTML
116 lines
14 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="github crates-io docs-rs"><meta name="keywords" content="rust, rustlang, rust-lang, paste"><title>paste - 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="../light.css" id="themeStyle"><link rel="stylesheet" type="text/css" href="../dark.css" disabled ><link rel="stylesheet" type="text/css" href="../ayu.css" disabled ><script id="default-settings"></script><script src="../storage.js"></script><script src="../crates.js"></script><noscript><link rel="stylesheet" href="../noscript.css"></noscript><link rel="icon" type="image/svg+xml" href="../favicon.svg">
|
||
<link rel="alternate icon" type="image/png" href="../favicon-16x16.png">
|
||
<link rel="alternate icon" type="image/png" href="../favicon-32x32.png"><style type="text/css">#crate-search{background-image:url("../down-arrow.svg");}</style></head><body class="rustdoc mod"><!--[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" role="button">☰</div><a href='../paste/index.html'><div class='logo-container rust-logo'><img src='../rust-logo.png' alt='logo'></div></a><p class="location">Crate paste</p><div class="block version"><p>Version 0.1.18</p></div><div class="sidebar-elems"><a id="all-types" href="all.html"><p>See all paste's items</p></a><div class="block items"><ul><li><a href="#macros">Macros</a></li></ul></div><p class="location"></p><div id="sidebar-vars" data-name="paste" data-ty="mod" data-relpath="../"></div></div></nav><div class="theme-picker"><button id="theme-picker" aria-label="Pick another theme!" aria-haspopup="menu"><img src="../brush.svg" width="18" height="18" alt="Pick another theme!"></button><div id="theme-choices" role="menu"></div></div><script src="../theme.js"></script><nav class="sub"><form class="search-form"><div class="search-container"><div><select id="crate-search"><option value="All crates">All crates</option></select><input class="search-input" name="search" disabled autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"></div><button type="button" class="help-button">?</button>
|
||
<a id="settings-menu" href="../settings.html"><img src="../wheel.svg" width="18" height="18" alt="Change settings"></a></div></form></nav><section id="main" class="content"><h1 class="fqn"><span class="in-band">Crate <a class="mod" href="">paste</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/paste/lib.rs.html#1-158" title="goto source code">[src]</a></span></h1><div class="docblock"><p><a href="https://github.com/dtolnay/paste"><img src="https://img.shields.io/badge/github-8da0cb?style=for-the-badge&labelColor=555555&logo=github" alt="github" /></a> <a href="https://crates.io/crates/paste"><img src="https://img.shields.io/badge/crates.io-fc8d62?style=for-the-badge&labelColor=555555&logo=rust" alt="crates-io" /></a> <a href="https://docs.rs/paste"><img src="https://img.shields.io/badge/docs.rs-66c2a5?style=for-the-badge&labelColor=555555&logoColor=white&logo=data:image/svg+xml;base64,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" alt="docs-rs" /></a></p>
|
||
<br>
|
||
<p>The nightly-only <a href="https://doc.rust-lang.org/std/macro.concat_idents.html"><code>concat_idents!</code></a> macro in the Rust standard library is
|
||
notoriously underpowered in that its concatenated identifiers can only refer to
|
||
existing items, they can never be used to define something new.</p>
|
||
<p>This crate provides a flexible way to paste together identifiers in a macro,
|
||
including using pasted identifiers to define new items.</p>
|
||
<p>This approach works with any stable or nightly Rust compiler 1.30+.</p>
|
||
<br>
|
||
<h1 id="pasting-identifiers" class="section-header"><a href="#pasting-identifiers">Pasting identifiers</a></h1>
|
||
<p>There are two entry points, <code>paste::expr!</code> for macros in expression position and
|
||
<code>paste::item!</code> for macros in item position.</p>
|
||
<p>Within either one, identifiers inside <code>[<</code>…<code>>]</code> are pasted together to form a
|
||
single identifier.</p>
|
||
|
||
<div class="example-wrap"><pre class="rust rust-example-rendered">
|
||
<span class="comment">// Macro in item position: at module scope or inside of an impl block.</span>
|
||
<span class="ident">paste</span>::<span class="macro">item</span><span class="macro">!</span> {
|
||
<span class="comment">// Defines a const called `QRST`.</span>
|
||
<span class="kw">const</span> [<span class="op"><</span><span class="ident">Q</span> <span class="ident">R</span> <span class="ident">S</span> <span class="ident">T</span><span class="op">></span>]: <span class="kw-2">&</span><span class="ident">str</span> <span class="op">=</span> <span class="string">"success!"</span>;
|
||
}
|
||
|
||
<span class="kw">fn</span> <span class="ident">main</span>() {
|
||
<span class="comment">// Macro in expression position: inside a function body.</span>
|
||
<span class="macro">assert_eq</span><span class="macro">!</span>(
|
||
<span class="ident">paste</span>::<span class="macro">expr</span><span class="macro">!</span> { [<span class="op"><</span><span class="ident">Q</span> <span class="ident">R</span> <span class="ident">S</span> <span class="ident">T</span><span class="op">></span>].<span class="ident">len</span>() },
|
||
<span class="number">8</span>,
|
||
);
|
||
}</pre></div>
|
||
<p><br><br></p>
|
||
<h1 id="more-elaborate-examples" class="section-header"><a href="#more-elaborate-examples">More elaborate examples</a></h1>
|
||
<p>This program demonstrates how you may want to bundle a paste invocation inside
|
||
of a more convenient user-facing macro of your own. Here the <code>routes!(A, B)</code>
|
||
macro expands to a vector containing <code>ROUTE_A</code> and <code>ROUTE_B</code>.</p>
|
||
|
||
<div class="example-wrap"><pre class="rust rust-example-rendered">
|
||
<span class="kw">const</span> <span class="ident">ROUTE_A</span>: <span class="kw-2">&</span><span class="ident">str</span> <span class="op">=</span> <span class="string">"/a"</span>;
|
||
<span class="kw">const</span> <span class="ident">ROUTE_B</span>: <span class="kw-2">&</span><span class="ident">str</span> <span class="op">=</span> <span class="string">"/b"</span>;
|
||
|
||
<span class="macro">macro_rules</span><span class="macro">!</span> <span class="ident">routes</span> {
|
||
($(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">route</span>:<span class="ident">ident</span>),<span class="kw-2">*</span>) <span class="op">=</span><span class="op">></span> {{
|
||
<span class="ident">paste</span>::<span class="macro">expr</span><span class="macro">!</span> {
|
||
<span class="macro">vec</span><span class="macro">!</span>[$( [<span class="op"><</span><span class="ident">ROUTE_</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">route</span><span class="op">></span>] ),<span class="kw-2">*</span>]
|
||
}
|
||
}}
|
||
}
|
||
|
||
<span class="kw">fn</span> <span class="ident">main</span>() {
|
||
<span class="kw">let</span> <span class="ident">routes</span> <span class="op">=</span> <span class="macro">routes</span><span class="macro">!</span>(<span class="ident">A</span>, <span class="ident">B</span>);
|
||
<span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">routes</span>, <span class="macro">vec</span><span class="macro">!</span>[<span class="string">"/a"</span>, <span class="string">"/b"</span>]);
|
||
}</pre></div>
|
||
<p>The next example shows a macro that generates accessor methods for some struct
|
||
fields.</p>
|
||
|
||
<div class="example-wrap"><pre class="rust rust-example-rendered">
|
||
<span class="macro">macro_rules</span><span class="macro">!</span> <span class="ident">make_a_struct_and_getters</span> {
|
||
(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">name</span>:<span class="ident">ident</span> { $(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">field</span>:<span class="ident">ident</span>),<span class="op">*</span> }) <span class="op">=</span><span class="op">></span> {
|
||
<span class="comment">// Define a struct. This expands to:</span>
|
||
<span class="comment">//</span>
|
||
<span class="comment">// pub struct S {</span>
|
||
<span class="comment">// a: String,</span>
|
||
<span class="comment">// b: String,</span>
|
||
<span class="comment">// c: String,</span>
|
||
<span class="comment">// }</span>
|
||
<span class="kw">pub</span> <span class="kw">struct</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">name</span> {
|
||
$(
|
||
<span class="macro-nonterminal">$</span><span class="macro-nonterminal">field</span>: <span class="ident">String</span>,
|
||
)<span class="op">*</span>
|
||
}
|
||
|
||
<span class="comment">// Build an impl block with getters. This expands to:</span>
|
||
<span class="comment">//</span>
|
||
<span class="comment">// impl S {</span>
|
||
<span class="comment">// pub fn get_a(&self) -> &str { &self.a }</span>
|
||
<span class="comment">// pub fn get_b(&self) -> &str { &self.b }</span>
|
||
<span class="comment">// pub fn get_c(&self) -> &str { &self.c }</span>
|
||
<span class="comment">// }</span>
|
||
<span class="ident">paste</span>::<span class="macro">item</span><span class="macro">!</span> {
|
||
<span class="kw">impl</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">name</span> {
|
||
$(
|
||
<span class="kw">pub</span> <span class="kw">fn</span> [<span class="op"><</span><span class="ident">get_</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">field</span><span class="op">></span>](<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="kw-2">&</span><span class="ident">str</span> {
|
||
<span class="kw-2">&</span><span class="self">self</span>.<span class="macro-nonterminal">$</span><span class="macro-nonterminal">field</span>
|
||
}
|
||
)<span class="op">*</span>
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
<span class="macro">make_a_struct_and_getters</span><span class="macro">!</span>(<span class="ident">S</span> { <span class="ident">a</span>, <span class="ident">b</span>, <span class="ident">c</span> });
|
||
|
||
<span class="kw">fn</span> <span class="ident">call_some_getters</span>(<span class="ident">s</span>: <span class="kw-2">&</span><span class="ident">S</span>) <span class="op">-</span><span class="op">></span> <span class="ident">bool</span> {
|
||
<span class="ident">s</span>.<span class="ident">get_a</span>() <span class="op">=</span><span class="op">=</span> <span class="ident">s</span>.<span class="ident">get_b</span>() <span class="op">&&</span> <span class="ident">s</span>.<span class="ident">get_c</span>().<span class="ident">is_empty</span>()
|
||
}</pre></div>
|
||
<p><br><br></p>
|
||
<h1 id="case-conversion" class="section-header"><a href="#case-conversion">Case conversion</a></h1>
|
||
<p>Use <code>$var:lower</code> or <code>$var:upper</code> in the segment list to convert an
|
||
interpolated segment to lower- or uppercase as part of the paste. For
|
||
example, <code>[<ld_ $reg:lower _expr>]</code> would paste to <code>ld_bc_expr</code> if invoked
|
||
with $reg=<code>Bc</code>.</p>
|
||
<p>Use <code>$var:snake</code> to convert CamelCase input to snake_case.
|
||
Use <code>$var:camel</code> to convert snake_case to CamelCase.
|
||
These compose, so for example <code>$var:snake:upper</code> would give you SCREAMING_CASE.</p>
|
||
<p>The precise Unicode conversions are as defined by <a href="https://doc.rust-lang.org/std/primitive.str.html#method.to_lowercase"><code>str::to_lowercase</code></a> and
|
||
<a href="https://doc.rust-lang.org/std/primitive.str.html#method.to_uppercase"><code>str::to_uppercase</code></a>.</p>
|
||
</div><h2 id="macros" class="section-header"><a href="#macros">Macros</a></h2>
|
||
<table><tr class="module-item"><td><a class="macro" href="macro.expr.html" title="paste::expr macro">expr</a></td><td class="docblock-short"><p>Paste identifiers within a macro invocation that expands to an expression.</p>
|
||
</td></tr><tr class="module-item"><td><a class="macro" href="macro.item.html" title="paste::item macro">item</a></td><td class="docblock-short"><p>Paste identifiers within a macro invocation that expands to one or more
|
||
items.</p>
|
||
</td></tr><tr class="module-item"><td><a class="macro" href="macro.item_with_macros.html" title="paste::item_with_macros macro">item_with_macros</a></td><td class="docblock-short"><p>Paste identifiers within a macro invocation that expands to one or more
|
||
macro_rules macros or items containing macros.</p>
|
||
</td></tr></table></section><section id="search" class="content hidden"></section><section class="footer"></section><div id="rustdoc-vars" data-root-path="../" data-current-crate="paste" data-search-js="../search-index.js"></div>
|
||
<script src="../main.js"></script></body></html> |