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<h1 class='fqn'><span class='in-band'>Trait <a href='index.html'>rustc_serialize</a>::<wbr><a class="trait" href=''>EncoderHelpers</a></span><span class='out-of-band'><span id='render-detail'>
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</span><a class='srclink' href='../src/rustc_serialize/serialize.rs.html#1460-1493' title='goto source code'>[src]</a></span></h1>
<pre class='rust trait'>pub trait EncoderHelpers: <a class="trait" href="../rustc_serialize/trait.Encoder.html" title="trait rustc_serialize::Encoder">Encoder</a> {
fn <a href='#tymethod.emit_from_vec' class='fnname'>emit_from_vec</a><T, F>(&mut self, v: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.slice.html">&[</a>T<a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.slice.html">]</a>, f: F) -> <a class="enum" href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html" title="enum core::result::Result">Result</a><<a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.tuple.html">()</a>, Self::<a class="trait" href="../rustc_serialize/trait.Encoder.html" title="trait rustc_serialize::Encoder">Error</a>><br> <span class="where">where<br> F: <a class="trait" href="https://doc.rust-lang.org/nightly/core/ops/trait.FnMut.html" title="trait core::ops::FnMut">FnMut</a>(&mut Self, &T) -> <a class="enum" href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html" title="enum core::result::Result">Result</a><<a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.tuple.html">()</a>, Self::<a class="trait" href="../rustc_serialize/trait.Encoder.html" title="trait rustc_serialize::Encoder">Error</a>></span>;
}</pre><div class='docblock'><p>Trait with helper functions for implementing <code>Encodable</code>.</p>
<p>This trait is implemented for everything that implements <code>Encoder</code>.
<code>Encodable</code> implementations can make use of it to make their implementations
easier.</p>
</div>
<h2 id='required-methods'>Required Methods</h2>
<div class='methods'>
<h3 id='tymethod.emit_from_vec' class='method'><span id='emit_from_vec.v' class='invisible'><code>fn <a href='#tymethod.emit_from_vec' class='fnname'>emit_from_vec</a><T, F>(&mut self, v: <a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.slice.html">&[</a>T<a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.slice.html">]</a>, f: F) -> <a class="enum" href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html" title="enum core::result::Result">Result</a><<a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.tuple.html">()</a>, Self::<a class="trait" href="../rustc_serialize/trait.Encoder.html" title="trait rustc_serialize::Encoder">Error</a>> <span class="where fmt-newline">where<br> F: <a class="trait" href="https://doc.rust-lang.org/nightly/core/ops/trait.FnMut.html" title="trait core::ops::FnMut">FnMut</a>(&mut Self, &T) -> <a class="enum" href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html" title="enum core::result::Result">Result</a><<a class="primitive" href="https://doc.rust-lang.org/nightly/std/primitive.tuple.html">()</a>, Self::<a class="trait" href="../rustc_serialize/trait.Encoder.html" title="trait rustc_serialize::Encoder">Error</a>>, </span></code></span></h3><div class='docblock'><p>Emit a vector as a sequence.</p>
<p>Storing sequences as vectors is a common pattern. This method makes
encoding such sequences easier by wrapping the calls to
<code>Encoder::emit_seq</code> and <code>Encoder::emit_seq_elt</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">rustc_serialize</span>::<span class="ident">Encodable</span>;
<span class="kw">use</span> <span class="ident">rustc_serialize</span>::<span class="ident">Encoder</span>;
<span class="kw">use</span> <span class="ident">rustc_serialize</span>::<span class="ident">EncoderHelpers</span>;
<span class="kw">struct</span> <span class="ident">NumberSequence</span> {
<span class="ident">elements</span>: <span class="ident">Vec</span><span class="op"><</span><span class="ident">i32</span><span class="op">></span>,
}
<span class="kw">impl</span> <span class="ident">Encodable</span> <span class="kw">for</span> <span class="ident">NumberSequence</span> {
<span class="kw">fn</span> <span class="ident">encode</span><span class="op"><</span><span class="ident">S</span>: <span class="ident">Encoder</span><span class="op">></span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">s</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">S</span>) <span class="op">-></span> <span class="prelude-ty">Result</span><span class="op"><</span>(), <span class="ident">S</span>::<span class="ident">Error</span><span class="op">></span> {
<span class="ident">s</span>.<span class="ident">emit_struct</span>(<span class="string">"NumberSequence"</span>, <span class="number">1</span>, <span class="op">|</span><span class="ident">s</span><span class="op">|</span> {
<span class="ident">s</span>.<span class="ident">emit_struct_field</span>(<span class="string">"elements"</span>, <span class="number">0</span>, <span class="op">|</span><span class="ident">s</span><span class="op">|</span> {
<span class="ident">s</span>.<span class="ident">emit_from_vec</span>(<span class="kw-2">&</span><span class="self">self</span>.<span class="ident">elements</span>, <span class="op">|</span><span class="ident">s</span>,<span class="ident">e</span><span class="op">|</span> {
<span class="ident">s</span>.<span class="ident">emit_i32</span>(<span class="kw-2">*</span><span class="ident">e</span>)
})
})
})
}
}</pre>
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<h2 id='implementors'>Implementors</h2>
<ul class='item-list' id='implementors-list'>
<li><code>impl<S: <a class="trait" href="../rustc_serialize/trait.Encoder.html" title="trait rustc_serialize::Encoder">Encoder</a>> EncoderHelpers for S</code></li>
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