<!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 `value` mod in crate `glib`."> <meta name="keywords" content="rust, rustlang, rust-lang, value"> <title>glib::value - 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 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"> <p class='location'>Module value</p><div class="block items"><ul><li><a href="#structs">Structs</a></li><li><a href="#traits">Traits</a></li></ul></div><p class='location'><a href='../index.html'>glib</a></p><script>window.sidebarCurrent = {name: 'value', ty: 'mod', 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'>Module <a href='../index.html'>glib</a>::<wbr><a class="mod" href=''>value</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/glib/value.rs.html#5-567' title='goto source code'>[src]</a></span></h1> <div class='docblock'><p><code>Value</code> binding and helper traits.</p> <p>The type of a <a href="struct.Value.html"><code>Value</code></a> is dynamic in that it generally isn't known at compile time but once created a <code>Value</code> can't change its type.</p> <p><a href="struct.TypedValue.html"><code>TypedValue</code></a> has a statically known type and dereferences to <code>Value</code> so it can be used everywhere <code>Value</code> references are accepted.</p> <p>Supported types are <code>bool</code>, <code>i8</code>, <code>u8</code>, <code>i32</code>, <code>u32</code>, <code>i64</code>, <code>u64</code>, <code>f32</code>, <code>f64</code>, <code>String</code> and objects (<code>T: IsA<Object></code>).</p> <h1 id='examples' class='section-header'><a href='#examples'>Examples</a></h1> <pre class="rust rust-example-rendered"> <span class="kw">use</span> <span class="ident">glib</span>::<span class="ident">prelude</span>::<span class="kw-2">*</span>; <span class="comment">// or `use gtk::prelude::*;`</span> <span class="kw">use</span> <span class="ident">glib</span>::{<span class="ident">TypedValue</span>, <span class="ident">Value</span>}; <span class="comment">// Value and TypedValue implement From<&i32>, From<&str></span> <span class="comment">// and From<Option<&str>>. Another option is the `ToValue` trait.</span> <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">num</span> <span class="op">=</span> <span class="number">10</span>.<span class="ident">to_value</span>(); <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">hello</span> <span class="op">=</span> <span class="ident">Value</span>::<span class="ident">from</span>(<span class="string">"Hello!"</span>); <span class="kw">let</span> <span class="ident">none</span>: <span class="prelude-ty">Option</span><span class="op"><</span><span class="kw-2">&</span><span class="ident">str</span><span class="op">></span> <span class="op">=</span> <span class="prelude-val">None</span>; <span class="kw">let</span> <span class="ident">str_none</span> <span class="op">=</span> <span class="ident">Value</span>::<span class="ident">from</span>(<span class="ident">none</span>.<span class="ident">clone</span>()); <span class="kw">let</span> <span class="ident">typed_str_none</span> <span class="op">=</span> <span class="ident">TypedValue</span>::<span class="ident">from</span>(<span class="ident">none</span>); <span class="comment">// `is` tests the type of the value.</span> <span class="macro">assert</span><span class="macro">!</span>(<span class="ident">num</span>.<span class="ident">is</span>::<span class="op"><</span><span class="ident">i32</span><span class="op">></span>()); <span class="macro">assert</span><span class="macro">!</span>(<span class="ident">hello</span>.<span class="ident">is</span>::<span class="op"><</span><span class="ident">String</span><span class="op">></span>()); <span class="comment">// `get` tries to get a value of specific type and returns None</span> <span class="comment">// if the type doesn't match or the value is None.</span> <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">num</span>.<span class="ident">get</span>(), <span class="prelude-val">Some</span>(<span class="number">10</span>)); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">num</span>.<span class="ident">get</span>::<span class="op"><</span><span class="ident">String</span><span class="op">></span>(), <span class="prelude-val">None</span>); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">hello</span>.<span class="ident">get</span>(), <span class="prelude-val">Some</span>(<span class="ident">String</span>::<span class="ident">from</span>(<span class="string">"Hello!"</span>))); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">hello</span>.<span class="ident">get</span>::<span class="op"><</span><span class="ident">String</span><span class="op">></span>(), <span class="prelude-val">Some</span>(<span class="ident">String</span>::<span class="ident">from</span>(<span class="string">"Hello!"</span>))); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">str_none</span>.<span class="ident">get</span>::<span class="op"><</span><span class="ident">String</span><span class="op">></span>(), <span class="prelude-val">None</span>); <span class="comment">// `typed` tries to convert a `Value` to `TypedValue`.</span> <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">typed_num</span> <span class="op">=</span> <span class="ident">num</span>.<span class="ident">downcast</span>::<span class="op"><</span><span class="ident">i32</span><span class="op">></span>().<span class="ident">unwrap</span>(); <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">typed_hello</span> <span class="op">=</span> <span class="ident">hello</span>.<span class="ident">downcast</span>::<span class="op"><</span><span class="ident">String</span><span class="op">></span>().<span class="ident">unwrap</span>(); <span class="comment">// `str_none` is not an `i32`</span> <span class="macro">assert</span><span class="macro">!</span>(<span class="ident">str_none</span>.<span class="ident">downcast</span>::<span class="op"><</span><span class="ident">i32</span><span class="op">></span>().<span class="ident">is_err</span>()); <span class="comment">// `get`</span> <span class="macro">assert</span><span class="macro">!</span>(<span class="ident">typed_hello</span>.<span class="ident">get</span>().<span class="ident">unwrap</span>() <span class="op">==</span> <span class="string">"Hello!"</span>); <span class="macro">assert</span><span class="macro">!</span>(<span class="ident">typed_str_none</span>.<span class="ident">get</span>() <span class="op">==</span> <span class="prelude-val">None</span>); <span class="comment">// Numeric types can't have value `None`, `get` always returns `Some`.</span> <span class="comment">// Such types have `get_some`, which avoids unnecessary `unwrap`ping.</span> <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">typed_num</span>.<span class="ident">get</span>().<span class="ident">unwrap</span>(), <span class="number">10</span>); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">typed_num</span>.<span class="ident">get_some</span>(), <span class="number">10</span>); <span class="comment">// `set_none` sets the value to `None` if the type supports it.</span> <span class="ident">typed_hello</span>.<span class="ident">set_none</span>(); <span class="macro">assert</span><span class="macro">!</span>(<span class="ident">typed_hello</span>.<span class="ident">get</span>().<span class="ident">is_none</span>()); <span class="comment">// `set` takes an optional reference for types that support `None`.</span> <span class="ident">typed_hello</span>.<span class="ident">set</span>(<span class="prelude-val">Some</span>(<span class="string">"Hello again!"</span>)); <span class="macro">assert</span><span class="macro">!</span>(<span class="ident">typed_hello</span>.<span class="ident">get</span>().<span class="ident">unwrap</span>() <span class="op">==</span> <span class="string">"Hello again!"</span>); <span class="comment">// `set_some` is the only setter for types that don't support `None`.</span> <span class="ident">typed_num</span>.<span class="ident">set_some</span>(<span class="kw-2">&</span><span class="number">20</span>); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">typed_num</span>.<span class="ident">get_some</span>(), <span class="number">20</span>);</pre> </div><h2 id='structs' class='section-header'><a href="#structs">Structs</a></h2> <table> <tr class=' module-item'> <td><a class="struct" href="struct.TypedValue.html" title='struct glib::value::TypedValue'>TypedValue</a></td> <td class='docblock-short'> <p>A statically typed <a href="struct.Value.html"><code>Value</code></a>.</p> </td> </tr> <tr class=' module-item'> <td><a class="struct" href="struct.Value.html" title='struct glib::value::Value'>Value</a></td> <td class='docblock-short'> <p>A generic value capable of carrying various types.</p> </td> </tr> <tr class=' module-item'> <td><a class="struct" href="struct.ValueArray.html" title='struct glib::value::ValueArray'>ValueArray</a></td> <td class='docblock-short'> </td> </tr></table><h2 id='traits' class='section-header'><a href="#traits">Traits</a></h2> <table> <tr class=' module-item'> <td><a class="trait" href="trait.FromValue.html" title='trait glib::value::FromValue'>FromValue</a></td> <td class='docblock-short'> <p>Extracts a value.</p> </td> </tr> <tr class=' module-item'> <td><a class="trait" href="trait.FromValueOptional.html" title='trait glib::value::FromValueOptional'>FromValueOptional</a></td> <td class='docblock-short'> <p>Extracts a value.</p> </td> </tr> <tr class=' module-item'> <td><a class="trait" href="trait.SetValue.html" title='trait glib::value::SetValue'>SetValue</a></td> <td class='docblock-short'> <p>Sets a value.</p> </td> </tr> <tr class=' module-item'> <td><a class="trait" href="trait.SetValueOptional.html" title='trait glib::value::SetValueOptional'>SetValueOptional</a></td> <td class='docblock-short'> <p>Sets a value.</p> </td> </tr> <tr class=' module-item'> <td><a class="trait" href="trait.ToValue.html" title='trait glib::value::ToValue'>ToValue</a></td> <td class='docblock-short'> <p>Converts to <code>Value</code>.</p> </td> </tr></table></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 = "../../"; 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