Home Explore Help
Sign In
RONCC
/
HPC-Tools-for-Quantum-Computing
Watch 1
Star 0
Fork 0
Files Issues 0 Pull Requests 0 Wiki
Tree: e971e022d2
Branches Tags
HPC-Tools-fo...
/
doc
/
syn
/
fn.parse.html

fn.parse.html 6.7 KB
History Raw

123456789101112131415161718192021222324252627282930313233343536 
  1. <!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 `parse` fn in crate `syn`."><meta name="keywords" content="rust, rustlang, rust-lang, parse"><title>syn::parse - 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="../light.css" id="themeStyle"><script src="../storage.js"></script></head><body class="rustdoc fn"><!--[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><div class="sidebar-elems"><p class='location'><a href='index.html'>syn</a></p><script>window.sidebarCurrent = {name: 'parse', ty: 'fn', relpath: ''};</script><script defer src="sidebar-items.js"></script></div></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"><a id="settings-menu" href="../settings.html"><img src="../wheel.svg" width="18" alt="Change settings"></a></div></form></nav><section id="main" class="content"><h1 class='fqn'><span class='in-band'>Function <a href='index.html'>syn</a>::<wbr><a class="fn" href=''>parse</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/syn/lib.rs.html#637-642' title='goto source code'>[src]</a></span></h1><pre class='rust fn'>pub fn parse&lt;T&gt;(tokens: <a class="struct" href="https://doc.rust-lang.org/nightly/proc_macro/struct.TokenStream.html" title="struct proc_macro::TokenStream">TokenStream</a>) -&gt; <a class="enum" href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html" title="enum core::result::Result">Result</a>&lt;T, <a class="struct" href="../syn/synom/struct.ParseError.html" title="struct syn::synom::ParseError">ParseError</a>&gt; <span class="where fmt-newline">where<br>&nbsp;&nbsp;&nbsp;&nbsp;T: <a class="trait" href="../syn/synom/trait.Synom.html" title="trait syn::synom::Synom">Synom</a>,&nbsp;</span></pre><div class='docblock'><p>Parse tokens of source code into the chosen syntax tree node.</p>
    2. 

  2. <p>This is preferred over parsing a string because tokens are able to preserve
    3. 

  3. information about where in the user's code they were originally written (the
    4. 

  4. &quot;span&quot; of the token), possibly allowing the compiler to produce better error
    5. 

  5. messages.</p>
    6. 

  6. <p>This function parses a <code>proc_macro::TokenStream</code> which is the type used for
    7. 

  7. interop with the compiler in a procedural macro. To parse a
    8. 

  8. <code>proc_macro2::TokenStream</code>, use <a href="fn.parse2.html"><code>syn::parse2</code></a> instead.</p>
    9. 

  9. <p><em>This function is available if Syn is built with both the <code>&quot;parsing&quot;</code> and
    10. 

  10. <code>&quot;proc-macro&quot;</code> features.</em></p>
    11. 

  11. <h1 id="examples" class="section-header"><a href="#examples">Examples</a></h1>
    12. 

  12. <pre class="rust rust-example-rendered">
    13. 

  13. <span class="kw">extern</span> <span class="kw">crate</span> <span class="ident">proc_macro</span>;
    14. 

  14. <span class="kw">use</span> <span class="ident">proc_macro</span>::<span class="ident">TokenStream</span>;
    15. 

  15. 

  16. <span class="kw">extern</span> <span class="kw">crate</span> <span class="ident">syn</span>;
    17. 

  17. 

  18. <span class="attribute">#[<span class="ident">macro_use</span>]</span>
    19. 

  19. <span class="kw">extern</span> <span class="kw">crate</span> <span class="ident">quote</span>;
    20. 

  20. 

  21. <span class="kw">use</span> <span class="ident">syn</span>::<span class="ident">DeriveInput</span>;
    22. 

  22. 

  23. <span class="attribute">#[<span class="ident">proc_macro_derive</span>(<span class="ident">MyMacro</span>)]</span>
    24. 

  24. <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">my_macro</span>(<span class="ident">input</span>: <span class="ident">TokenStream</span>) <span class="op">-&gt;</span> <span class="ident">TokenStream</span> {
    25. 

  25.     <span class="comment">// Parse the tokens into a syntax tree</span>
    26. 

  26.     <span class="kw">let</span> <span class="ident">ast</span>: <span class="ident">DeriveInput</span> <span class="op">=</span> <span class="ident">syn</span>::<span class="ident">parse</span>(<span class="ident">input</span>).<span class="ident">unwrap</span>();
    27. 

  27. 

  28.     <span class="comment">// Build the output, possibly using quasi-quotation</span>
    29. 

  29.     <span class="kw">let</span> <span class="ident">expanded</span> <span class="op">=</span> <span class="macro">quote</span><span class="macro">!</span> {
    30. 

  30.         <span class="comment">/* ... */</span>
    31. 

  31.     };
    32. 

  32. 

  33.     <span class="comment">// Convert into a token stream and return it</span>
    34. 

  34.     <span class="ident">expanded</span>.<span class="ident">into</span>()
    35. 

  35. }</pre>
    36. 

  36. </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><p>Search multiple things at once by splitting your query with comma (e.g. <code>str,u8</code> or <code>String,struct:Vec,test</code>)</p></div></div></aside><script>window.rootPath = "../";window.currentCrate = "syn";</script><script src="../aliases.js"></script><script src="../main.js"></script><script defer src="../search-index.js"></script></body></html>
    37.