<!DOCTYPE html><htmllang="en"><head><metacharset="utf-8"><metaname="viewport"content="width=device-width, initial-scale=1.0"><metaname="generator"content="rustdoc"><metaname="description"content="Store a cached key/value pair, only recalculating when the key changes."><metaname="keywords"content="rust, rustlang, rust-lang, Cached"><title>Cached in widgetry - Rust</title><linkrel="stylesheet"type="text/css"href="../normalize.css"><linkrel="stylesheet"type="text/css"href="../rustdoc.css"id="mainThemeStyle"><linkrel="stylesheet"type="text/css"href="../light.css"id="themeStyle"><linkrel="stylesheet"type="text/css"href="../dark.css"disabled><linkrel="stylesheet"type="text/css"href="../ayu.css"disabled><scriptid="default-settings"></script><scriptsrc="../storage.js"></script><scriptsrc="../crates.js"></script><noscript><linkrel="stylesheet"href="../noscript.css"></noscript><linkrel="icon"type="image/svg+xml"href="../favicon.svg"><linkrel="alternate icon"type="image/png"href="../favicon-16x16.png"><linkrel="alternate icon"type="image/png"href="../favicon-32x32.png"><styletype="text/css">#crate-search{background-image:url("../down-arrow.svg");}</style></head><bodyclass="rustdoc struct"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><navclass="sidebar"><divclass="sidebar-menu"role="button">☰</div><ahref='../widgetry/index.html'><divclass='logo-container rust-logo'><imgsrc='../rust-logo.png'alt='logo'></div></a><h2class="location">Struct Cached</h2><divclass="sidebar-elems"><divclass="block items"><h3class="sidebar-title"><ahref="#fields">Fields</a></h3><divclass="sidebar-links"><ahref="#structfield.contents">contents</a></div><h3class="sidebar-title"><ahref="#implementations">Methods</a></h3><divclass="sidebar-links"><ahref="#method.clear">clear</a><ahref="#method.key">key</a><ahref="#method.new">new</a><ahref="#method.set">set</a><ahref="#method.update">update</a><ahref="#method.value">value</a></div><h3class="sidebar-title"><ahref="#trait-implementations">Trait Implementations</a></h3><divclass="sidebar-links"><ahref="#impl-Default">Default</a></div><h3class="sidebar-title"><ahref="#synthetic-implementations">Auto Trait Implementations</a></h3><divclass="sidebar-links"><ahref="#impl-RefUnwindSafe">RefUnwindSafe</a><ahref="#impl-Send">Send</a><ahref="#impl-Sync">Sync</a><ahref="#impl-Unpin">Unpin</a><ahref="#impl-UnwindSafe">UnwindSafe</a></div><h3class="sidebar-title"><ahref="#blanket-implementations">Blanket Implementations</a></h3><divclass="sidebar-links"><ahref="#impl-Any">Any</a><ahref="#impl-Borrow%3CT%3E">Borrow<T></a><ahref="#impl-BorrowMut%3CT%3E">BorrowMut<T></a><ahref="#impl-Downcast">Downcast</a><ahref="#impl-DowncastSync">DowncastSync</a><ahref="#impl-From%3CT%3E">From<T></a><ahref="#impl-Into%3CU%3E">Into<U></a><ahref="#impl-Same%3CT%3E">Same<T></a><ahref="#impl-TryFrom%3CU%3E">TryFrom<U></a><ahref="#impl-TryInto%3CU%3E">TryInto<U></a></div></div><h2class="location">Other items in<br><ahref="index.html">widgetry</a></h2><divid="sidebar-vars"data-name="Cached"data-ty="struct"data-relpath=""></div><scriptdefersrc="sidebar-items.js"></script></div></nav><divclass="theme-picker"><buttonid="theme-picker"aria-label="Pick another theme!"aria-haspopup="menu"title="themes"><imgwidth="18"height="18"alt="Pick another theme!"src="../brush.svg"></button><divid="theme-choices"role="menu"></div></div><navclass="sub"><formclass="search-form"><divclass="search-container"><div><selectid="crate-search"><optionvalue="All crates">All crates</option></select><inputclass="search-input"name="search"disabledautocomplete="off"spellcheck="false"placeholder="Click or press ‘S’ to search, ‘?’ for more options…"type="search"></div><buttontype="button"id="help-button"title="help">?</button><aid="settings-menu"href="../settings.html"title="settings"><imgwidth="18"hei
}</pre></div><detailsclass="rustdoc-toggle top-doc"open><summaryclass="hideme"><span>Expand description</span></summary><divclass="docblock"><p>Store a cached key/value pair, only recalculating when the key changes.</p>
</div></details><detailsclass="rustdoc-toggle method-toggle"open><summary><divid="method.value"class="method has-srclink"><divclass="rightside"><aclass="srclink"href="../src/widgetry/tools/mod.rs.html#20-22"title="goto source code">[src]</a></div><ahref="#method.value"class="anchor"></a><h4class="code-header">pub fn <ahref="#method.value"class="fnname">value</a>(&self) -><aclass="enum"href="https://doc.rust-lang.org/1.55.0/core/option/enum.Option.html"title="enum core::option::Option">Option</a><<aclass="primitive"href="https://doc.rust-lang.org/1.55.0/std/primitive.reference.html">&</a>V></h4></div></summary><divclass="docblock"><p>Get the current value.</p>
</div></details><detailsclass="rustdoc-toggle method-toggle"open><summary><divid="method.update"class="method has-srclink"><divclass="rightside"><aclass="srclink"href="../src/widgetry/tools/mod.rs.html#25-33"title="goto source code">[src]</a></div><ahref="#method.update"class="anchor"></a><h4class="code-header">pub fn <ahref="#method.update"class="fnname">update</a><F: <aclass="trait"href="https://doc.rust-lang.org/1.55.0/core/ops/function/trait.FnMut.html"title="trait core::ops::function::FnMut">FnMut</a>(K) -> V>(&mut self, key: <aclass="enum"href="https://doc.rust-lang.org/1.55.0/core/option/enum.Option.html"title="enum core::option::Option">Option</a><K>, produce_value: F)</h4></div></summary><divclass="docblock"><p>Update the value if the key has changed.</p>
</div></details><detailsclass="rustdoc-toggle method-toggle"open><summary><divid="method.set"class="method has-srclink"><divclass="rightside"><aclass="srclink"href="../src/widgetry/tools/mod.rs.html#37-39"title="goto source code">[src]</a></div><ahref="#method.set"class="anchor"></a><h4class="code-header">pub fn <ahref="#method.set"class="fnname">set</a>(&mut self, key: K, value: V)</h4></div></summary><divclass="docblock"><p><code>update</code> is preferred, but sometimes <code>produce_value</code> needs to borrow the same struct that
then be further <code>downcast</code> into <code>Box<ConcreteType></code> where <code>ConcreteType</code> implements <code>Trait</code>. <ahref="#tymethod.into_any">Read more</a></p>
further <code>downcast</code> into <code>Rc<ConcreteType></code> where <code>ConcreteType</code> implements <code>Trait</code>. <ahref="#tymethod.into_any_rc">Read more</a></p>
further <code>downcast</code> into <code>Arc<ConcreteType></code> where <code>ConcreteType</code> implements <code>Trait</code>. <ahref="#tymethod.into_any_arc">Read more</a></p>
</div></details></div></details><detailsclass="rustdoc-toggle implementors-toggle"open><summary><divid="impl-Into%3CU%3E"class="impl has-srclink"><divclass="rightside"><aclass="srclink"href="https://doc.rust-lang.org/1.55.0/src/core/convert/mod.rs.html#535-542"title="goto source code">[src]</a></div><ahref="#impl-Into%3CU%3E"class="anchor"></a><h3class="code-header in-band">impl<T, U><aclass="trait"href="https://doc.rust-lang.org/1.55.0/core/convert/trait.Into.html"title="trait core::convert::Into">Into</a><U> for T <spanclass="where fmt-newline">where<br> U: <aclass="trait"href="https://doc.rust-lang.org/1.55.0/core/convert/trait.From.html"title="trait core::convert::From">From</a><T>, </span></h3></div></summary><divclass="impl-items"><detailsclass="rustdoc-toggle method-toggle"open><summary><divid="method.into"class="method trait-impl has-srclink"><divclass="rightside"><aclass="srclink"href="https://doc.rust-lang.org/1.55.0/src/core/convert/mod.rs.html#539"title="goto source code">[src]</a></div><ahref="#method.into"class="anchor"></a><h4class="code-header">pub fn <ahref="https://doc.rust-lang.org/1.55.0/core/convert/trait.Into.html#tymethod.into"class="fnname">into</a>(self) -> U</h4></div></summary><divclass='docblock'><p>Performs the conversion.</p>
</div></details></div></details><detailsclass="rustdoc-toggle implementors-toggle"open><summary><divid="impl-Same%3CT%3E"class="impl has-srclink"><divclass="rightside"></div><ahref="#impl-Same%3CT%3E"class="anchor"></a><h3class="code-header in-band">impl<T> Same<T> for T</h3></div></summary><divclass="impl-items"><detailsclass="rustdoc-toggle"open><summary><divid="associatedtype.Output"class="type trait-impl has-srclink"><ahref="#associatedtype.Output"class="anchor"></a><h4class="code-header">type <ahref="#associatedtype.Output"class="type">Output</a> = T</h4></div></summary><divclass='docblock'><p>Should always be <code>Self</code></p>
</div></details></div></details><detailsclass="rustdoc-toggle implementors-toggle"open><summary><divid="impl-TryFrom%3CU%3E"class="impl has-srclink"><divclass="rightside"><aclass="srclink"href="https://doc.rust-lang.org/1.55.0/src/core/convert/mod.rs.html#583-592"title="goto source code">[src]</a></div><ahref="#impl-TryFrom%3CU%3E"class="anchor"></a><h3class="code-header in-band">impl<T, U><aclass="trait"href="https://doc.rust-lang.org/1.55.0/core/convert/trait.TryFrom.html"title="trait core::convert::TryFrom">TryFrom</a><U> for T <spanclass="where fmt-newline">where<br> U: <aclass="trait"href="https://doc.rust-lang.org/1.55.0/core/convert/trait.Into.html"title="trait core::convert::Into">Into</a><T>, </span></h3></div></summary><divclass="impl-items"><detailsclass="rustdoc-toggle"open><summary><divid="associatedtype.Error"class="type trait-impl has-srclink"><ahref="#associatedtype.Error"class="anchor"></a><h4class="code-header">type <ahref="https://doc.rust-lang.org/1.55.0/core/convert/trait.TryFrom.html#associatedtype.Error"class="type">Error</a> = <aclass="enum"href="https://doc.rust-lang.org/1.55.0/core/convert/enum.Infallible.html"title="enum core::convert::Infallible">Infallible</a></h4></div></summary><divclass='docblock'><p>The type returned in the event of a conversion error.</p>
</div></details><detailsclass="rustdoc-toggle method-toggle"open><summary><divid="method.try_from"class="method trait-impl has-srclink"><divclass="rightside"><aclass="srclink"href="https://doc.rust-lang.org/1.55.0/src/core/convert/mod.rs.html#589"title="goto source code">[src]</a></div><ahref="#method.try_from"class="anchor"></a><h4class="code-header">pub fn <ahref="https://doc.rust-lang.org/1.55.0/core/convert/trait.TryFrom.html#tymethod.try_from"class="fnname">try_from</a>(value: U) -><aclass="enum"href="https://doc.rust-lang.org/1.55.0/core/result/enum.Result.html"title="enum core::result::Result">Result</a><T, <T as <aclass="trait"href="https://doc.rust-lang.org/1.55.0/core/convert/trait.TryFrom.html"title="trait core::convert::TryFrom">TryFrom</a><U>>::<aclass="type"href="https://doc.rust-lang.org/1.55.0/core/convert/trait.TryFrom.html#associatedtype.Error"title="type core::convert::TryFrom::Error">Error</a>></h4></div></summary><divclass='docblock'><p>Performs the conversion.</p>
</div></details></div></details><detailsclass="rustdoc-toggle implementors-toggle"open><summary><divid="impl-TryInto%3CU%3E"class="impl has-srclink"><divclass="rightside"><aclass="srclink"href="https://doc.rust-lang.org/1.55.0/src/core/convert/mod.rs.html#569-578"title="goto source code">[src]</a></div><ahref="#impl-TryInto%3CU%3E"class="anchor"></a><h3class="code-header in-band">impl<T, U><aclass="trait"href="https://doc.rust-lang.org/1.55.0/core/convert/trait.TryInto.html"title="trait core::convert::TryInto">TryInto</a><U> for T <spanclass="where fmt-newline">where<br> U: <aclass="trait"href="https://doc.rust-lang.org/1.55.0/core/convert/trait.TryFrom.html"title="trait core::convert::TryFrom">TryFrom</a><T>, </span></h3></div></summary><divclass="impl-items"><detailsclass="rustdoc-toggle"open><summary><divid="associatedtype.Error-1"class="type trait-impl has-srclink"><ahref="#associatedtype.Error-1"class="anchor"></a><h4class="code-header">type <ahref="https://doc.rust-lang.org/1.55.0/core/convert/trait.TryInto.html#associatedtype.Error"class="type">Error</a> = <U as <aclass="trait"href="https://doc.rust-lang.org/1.55.0/core/convert/trait.TryFrom.html"title="trait core::convert::TryFrom">TryFrom</a><T>>::<aclass="type"href="https://doc.rust-lang.org/1.55.0/core/convert/trait.TryFrom.html#associatedtype.Error"title="type core::convert::TryFrom::Error">Error</a></h4></div></summary><divclass='docblock'><p>The type returned in the event of a conversion error.</p>
</div></details><detailsclass="rustdoc-toggle method-toggle"open><summary><divid="method.try_into"class="method trait-impl has-srclink"><divclass="rightside"><aclass="srclink"href="https://doc.rust-lang.org/1.55.0/src/core/convert/mod.rs.html#575"title="goto source code">[src]</a></div><ahref="#method.try_into"class="anchor"></a><h4class="code-header">pub fn <ahref="https://doc.rust-lang.org/1.55.0/core/convert/trait.TryInto.html#tymethod.try_into"class="fnname">try_into</a>(self) -><aclass="enum"href="https://doc.rust-lang.org/1.55.0/core/result/enum.Result.html"title="enum core::result::Result">Result</a><U, <U as <aclass="trait"href="https://doc.rust-lang.org/1.55.0/core/convert/trait.TryFrom.html"title="trait core::convert::TryFrom">TryFrom</a><T>>::<aclass="type"href="https://doc.rust-lang.org/1.55.0/core/convert/trait.TryFrom.html#associatedtype.Error"title="type core::convert::TryFrom::Error">Error</a>></h4></div></summary><divclass='docblock'><p>Performs the conversion.</p>
