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<span class="doccomment">/// An iterator that produces only the `T` values as long as the</span>
<span class="doccomment">/// inner iterator produces `Ok(T)`.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Used by [`process_results`](../fn.process_results.html), see its docs</span>
<span class="doccomment">/// for more information.</span>
<span class="attribute">#[<span class="ident">must_use</span> <span class="op">=</span> <span class="string">"iterator adaptors are lazy and do nothing unless consumed"</span>]</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Debug</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">ProcessResults</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="ident">I</span>, <span class="ident">E</span>: <span class="lifetime">'a</span><span class="op">></span> {
<span class="ident">error</span>: <span class="kw-2">&</span><span class="lifetime">'a</span> <span class="kw-2">mut</span> <span class="prelude-ty">Result</span><span class="op"><</span>(), <span class="ident">E</span><span class="op">></span>,
<span class="ident">iter</span>: <span class="ident">I</span>,
}
<span class="kw">impl</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="ident">I</span>, <span class="ident">T</span>, <span class="ident">E</span><span class="op">></span> <span class="ident">Iterator</span> <span class="kw">for</span> <span class="ident">ProcessResults</span><span class="op"><</span><span class="lifetime">'a</span>, <span class="ident">I</span>, <span class="ident">E</span><span class="op">></span>
<span class="kw">where</span> <span class="ident">I</span>: <span class="ident">Iterator</span><span class="op"><</span><span class="ident">Item</span> <span class="op">=</span> <span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">T</span>, <span class="ident">E</span><span class="op">></span><span class="op">></span>
{
<span class="kw">type</span> <span class="ident">Item</span> <span class="op">=</span> <span class="ident">T</span>;
<span class="kw">fn</span> <span class="ident">next</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="prelude-ty">Option</span><span class="op"><</span><span class="self">Self</span><span class="ident">::Item</span><span class="op">></span> {
<span class="kw">match</span> <span class="self">self</span>.<span class="ident">iter</span>.<span class="ident">next</span>() {
<span class="prelude-val">Some</span>(<span class="prelude-val">Ok</span>(<span class="ident">x</span>)) <span class="op">=</span><span class="op">></span> <span class="prelude-val">Some</span>(<span class="ident">x</span>),
<span class="prelude-val">Some</span>(<span class="prelude-val">Err</span>(<span class="ident">e</span>)) <span class="op">=</span><span class="op">></span> {
<span class="kw-2">*</span><span class="self">self</span>.<span class="ident">error</span> <span class="op">=</span> <span class="prelude-val">Err</span>(<span class="ident">e</span>);
<span class="prelude-val">None</span>
}
<span class="prelude-val">None</span> <span class="op">=</span><span class="op">></span> <span class="prelude-val">None</span>,
}
}
<span class="kw">fn</span> <span class="ident">size_hint</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-</span><span class="op">></span> (<span class="ident">usize</span>, <span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">usize</span><span class="op">></span>) {
<span class="kw">let</span> (<span class="kw">_</span>, <span class="ident">hi</span>) <span class="op">=</span> <span class="self">self</span>.<span class="ident">iter</span>.<span class="ident">size_hint</span>();
(<span class="number">0</span>, <span class="ident">hi</span>)
}
}
<span class="doccomment">/// “Lift” a function of the values of an iterator so that it can process</span>
<span class="doccomment">/// an iterator of `Result` values instead.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// `iterable` is an iterator or iterable with `Result<T, E>` elements, where</span>
<span class="doccomment">/// `T` is the value type and `E` the error type.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// `processor` is a closure that receives an adapted version of the iterable</span>
<span class="doccomment">/// as the only argument — the adapted iterator produces elements of type `T`,</span>
<span class="doccomment">/// as long as the original iterator produces `Ok` values.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// If the original iterable produces an error at any point, the adapted</span>
<span class="doccomment">/// iterator ends and the `process_results` function will return the</span>
<span class="doccomment">/// error iself.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Otherwise, the return value from the closure is returned wrapped</span>
<span class="doccomment">/// inside `Ok`.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Example</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use itertools::process_results;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// type R = Result<i32, &'static str>;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let first_values: Vec<R> = vec![Ok(1), Ok(0), Ok(3)];</span>
<span class="doccomment">/// let second_values: Vec<R> = vec![Ok(2), Ok(1), Err("overflow")];</span>
<span class="doccomment">///</span>
<span class="doccomment">/// // “Lift” the iterator .max() method to work on the values in Results using process_results</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let first_max = process_results(first_values, |iter| iter.max().unwrap_or(0));</span>
<span class="doccomment">/// let second_max = process_results(second_values, |iter| iter.max().unwrap_or(0));</span>
<span class="doccomment">///</span>
<span class="doccomment">/// assert_eq!(first_max, Ok(3));</span>
<span class="doccomment">/// assert!(second_max.is_err());</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">process_results</span><span class="op"><</span><span class="ident">I</span>, <span class="ident">F</span>, <span class="ident">T</span>, <span class="ident">E</span>, <span class="ident">R</span><span class="op">></span>(<span class="ident">iterable</span>: <span class="ident">I</span>, <span class="ident">processor</span>: <span class="ident">F</span>) <span class="op">-</span><span class="op">></span> <span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">R</span>, <span class="ident">E</span><span class="op">></span>
<span class="kw">where</span> <span class="ident">I</span>: <span class="ident">IntoIterator</span><span class="op"><</span><span class="ident">Item</span> <span class="op">=</span> <span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">T</span>, <span class="ident">E</span><span class="op">></span><span class="op">></span>,
<span class="ident">F</span>: <span class="ident">FnOnce</span>(<span class="ident">ProcessResults</span><span class="op"><</span><span class="ident">I::IntoIter</span>, <span class="ident">E</span><span class="op">></span>) <span class="op">-</span><span class="op">></span> <span class="ident">R</span>
{
<span class="kw">let</span> <span class="ident">iter</span> <span class="op">=</span> <span class="ident">iterable</span>.<span class="ident">into_iter</span>();
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">error</span> <span class="op">=</span> <span class="prelude-val">Ok</span>(());
<span class="kw">let</span> <span class="ident">result</span> <span class="op">=</span> <span class="ident">processor</span>(<span class="ident">ProcessResults</span> { <span class="ident">error</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">error</span>, <span class="ident">iter</span>: <span class="ident">iter</span> });
<span class="ident">error</span>.<span class="ident">map</span>(<span class="op">|</span><span class="kw">_</span><span class="op">|</span> <span class="ident">result</span>)
}
</pre></div>
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