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</pre><pre class="rust">
<span class="doccomment">//! Some iterator that produces tuples</span>
<span class="kw">use</span> <span class="ident">std::iter::Fuse</span>;
<span class="doccomment">/// An iterator over a incomplete tuple.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// See [`.tuples()`](../trait.Itertools.html#method.tuples) and</span>
<span class="doccomment">/// [`Tuples::into_buffer()`](struct.Tuples.html#method.into_buffer).</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">TupleBuffer</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>
<span class="kw">where</span> <span class="ident">T</span>: <span class="ident">TupleCollect</span>
{
<span class="ident">cur</span>: <span class="ident">usize</span>,
<span class="ident">buf</span>: <span class="ident">T::Buffer</span>,
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="ident">TupleBuffer</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>
<span class="kw">where</span> <span class="ident">T</span>: <span class="ident">TupleCollect</span>
{
<span class="kw">fn</span> <span class="ident">new</span>(<span class="ident">buf</span>: <span class="ident">T::Buffer</span>) <span class="op">-</span><span class="op">></span> <span class="self">Self</span> {
<span class="ident">TupleBuffer</span> {
<span class="ident">cur</span>: <span class="number">0</span>,
<span class="ident">buf</span>: <span class="ident">buf</span>,
}
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="ident">Iterator</span> <span class="kw">for</span> <span class="ident">TupleBuffer</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>
<span class="kw">where</span> <span class="ident">T</span>: <span class="ident">TupleCollect</span>
{
<span class="kw">type</span> <span class="ident">Item</span> <span class="op">=</span> <span class="ident">T::Item</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">let</span> <span class="ident">s</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">buf</span>.<span class="ident">as_mut</span>();
<span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="kw-2">ref</span> <span class="kw-2">mut</span> <span class="ident">item</span>) <span class="op">=</span> <span class="ident">s</span>.<span class="ident">get_mut</span>(<span class="self">self</span>.<span class="ident">cur</span>) {
<span class="self">self</span>.<span class="ident">cur</span> <span class="op">+</span><span class="op">=</span> <span class="number">1</span>;
<span class="ident">item</span>.<span class="ident">take</span>()
} <span class="kw">else</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="ident">buffer</span> <span class="op">=</span> <span class="kw-2">&</span><span class="self">self</span>.<span class="ident">buf</span>.<span class="ident">as_ref</span>()[<span class="self">self</span>.<span class="ident">cur</span>..];
<span class="kw">let</span> <span class="ident">len</span> <span class="op">=</span> <span class="kw">if</span> <span class="ident">buffer</span>.<span class="ident">len</span>() <span class="op">=</span><span class="op">=</span> <span class="number">0</span> {
<span class="number">0</span>
} <span class="kw">else</span> {
<span class="ident">buffer</span>.<span class="ident">iter</span>()
.<span class="ident">position</span>(<span class="op">|</span><span class="ident">x</span><span class="op">|</span> <span class="ident">x</span>.<span class="ident">is_none</span>())
.<span class="ident">unwrap_or</span>(<span class="ident">buffer</span>.<span class="ident">len</span>())
};
(<span class="ident">len</span>, <span class="prelude-val">Some</span>(<span class="ident">len</span>))
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="ident">ExactSizeIterator</span> <span class="kw">for</span> <span class="ident">TupleBuffer</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>
<span class="kw">where</span> <span class="ident">T</span>: <span class="ident">TupleCollect</span>
{
}
<span class="doccomment">/// An iterator that groups the items in tuples of a specific size.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// See [`.tuples()`](../trait.Itertools.html#method.tuples) 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="kw">pub</span> <span class="kw">struct</span> <span class="ident">Tuples</span><span class="op"><</span><span class="ident">I</span>, <span class="ident">T</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="ident">T::Item</span><span class="op">></span>,
<span class="ident">T</span>: <span class="ident">TupleCollect</span>
{
<span class="ident">iter</span>: <span class="ident">Fuse</span><span class="op"><</span><span class="ident">I</span><span class="op">></span>,
<span class="ident">buf</span>: <span class="ident">T::Buffer</span>,
}
<span class="doccomment">/// Create a new tuples iterator.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">tuples</span><span class="op"><</span><span class="ident">I</span>, <span class="ident">T</span><span class="op">></span>(<span class="ident">iter</span>: <span class="ident">I</span>) <span class="op">-</span><span class="op">></span> <span class="ident">Tuples</span><span class="op"><</span><span class="ident">I</span>, <span class="ident">T</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="ident">T::Item</span><span class="op">></span>,
<span class="ident">T</span>: <span class="ident">TupleCollect</span>
{
<span class="ident">Tuples</span> {
<span class="ident">iter</span>: <span class="ident">iter</span>.<span class="ident">fuse</span>(),
<span class="ident">buf</span>: <span class="ident">Default::default</span>(),
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">I</span>, <span class="ident">T</span><span class="op">></span> <span class="ident">Iterator</span> <span class="kw">for</span> <span class="ident">Tuples</span><span class="op"><</span><span class="ident">I</span>, <span class="ident">T</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="ident">T::Item</span><span class="op">></span>,
<span class="ident">T</span>: <span class="ident">TupleCollect</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="ident">T</span><span class="op">></span> {
<span class="ident">T::collect_from_iter</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>.<span class="ident">iter</span>, <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>.<span class="ident">buf</span>)
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">I</span>, <span class="ident">T</span><span class="op">></span> <span class="ident">Tuples</span><span class="op"><</span><span class="ident">I</span>, <span class="ident">T</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="ident">T::Item</span><span class="op">></span>,
<span class="ident">T</span>: <span class="ident">TupleCollect</span>
{
<span class="doccomment">/// Return a buffer with the produced items that was not enough to be grouped in a tuple.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">/// use itertools::Itertools;</span>
<span class="doccomment">///</span>
<span class="doccomment">/// let mut iter = (0..5).tuples();</span>
<span class="doccomment">/// assert_eq!(Some((0, 1, 2)), iter.next());</span>
<span class="doccomment">/// assert_eq!(None, iter.next());</span>
<span class="doccomment">/// itertools::assert_equal(vec![3, 4], iter.into_buffer());</span>
<span class="doccomment">/// ```</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">into_buffer</span>(<span class="self">self</span>) <span class="op">-</span><span class="op">></span> <span class="ident">TupleBuffer</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="ident">TupleBuffer::new</span>(<span class="self">self</span>.<span class="ident">buf</span>)
}
}
<span class="doccomment">/// An iterator over all contiguous windows that produces tuples of a specific size.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// See [`.tuple_windows()`](../trait.Itertools.html#method.tuple_windows) for more</span>
<span class="doccomment">/// 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">TupleWindows</span><span class="op"><</span><span class="ident">I</span>, <span class="ident">T</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="ident">T::Item</span><span class="op">></span>,
<span class="ident">T</span>: <span class="ident">TupleCollect</span>
{
<span class="ident">iter</span>: <span class="ident">I</span>,
<span class="ident">last</span>: <span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>,
}
<span class="doccomment">/// Create a new tuple windows iterator.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">tuple_windows</span><span class="op"><</span><span class="ident">I</span>, <span class="ident">T</span><span class="op">></span>(<span class="kw-2">mut</span> <span class="ident">iter</span>: <span class="ident">I</span>) <span class="op">-</span><span class="op">></span> <span class="ident">TupleWindows</span><span class="op"><</span><span class="ident">I</span>, <span class="ident">T</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="ident">T::Item</span><span class="op">></span>,
<span class="ident">T</span>: <span class="ident">TupleCollect</span>,
<span class="ident">T::Item</span>: <span class="ident">Clone</span>
{
<span class="kw">use</span> <span class="ident">std::iter::once</span>;
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">last</span> <span class="op">=</span> <span class="prelude-val">None</span>;
<span class="kw">if</span> <span class="ident">T::num_items</span>() <span class="op">!</span><span class="op">=</span> <span class="number">1</span> {
<span class="comment">// put in a duplicate item in front of the tuple; this simplifies</span>
<span class="comment">// .next() function.</span>
<span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="ident">item</span>) <span class="op">=</span> <span class="ident">iter</span>.<span class="ident">next</span>() {
<span class="kw">let</span> <span class="ident">iter</span> <span class="op">=</span> <span class="ident">once</span>(<span class="ident">item</span>.<span class="ident">clone</span>()).<span class="ident">chain</span>(<span class="ident">once</span>(<span class="ident">item</span>)).<span class="ident">chain</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">iter</span>);
<span class="ident">last</span> <span class="op">=</span> <span class="ident">T::collect_from_iter_no_buf</span>(<span class="ident">iter</span>);
}
}
<span class="ident">TupleWindows</span> {
<span class="ident">last</span>: <span class="ident">last</span>,
<span class="ident">iter</span>: <span class="ident">iter</span>,
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">I</span>, <span class="ident">T</span><span class="op">></span> <span class="ident">Iterator</span> <span class="kw">for</span> <span class="ident">TupleWindows</span><span class="op"><</span><span class="ident">I</span>, <span class="ident">T</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="ident">T::Item</span><span class="op">></span>,
<span class="ident">T</span>: <span class="ident">TupleCollect</span> <span class="op">+</span> <span class="ident">Clone</span>,
<span class="ident">T::Item</span>: <span class="ident">Clone</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="ident">T</span><span class="op">></span> {
<span class="kw">if</span> <span class="ident">T::num_items</span>() <span class="op">=</span><span class="op">=</span> <span class="number">1</span> {
<span class="kw">return</span> <span class="ident">T::collect_from_iter_no_buf</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>.<span class="ident">iter</span>)
}
<span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="kw-2">ref</span> <span class="kw-2">mut</span> <span class="ident">last</span>) <span class="op">=</span> <span class="self">self</span>.<span class="ident">last</span> {
<span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="ident">new</span>) <span class="op">=</span> <span class="self">self</span>.<span class="ident">iter</span>.<span class="ident">next</span>() {
<span class="ident">last</span>.<span class="ident">left_shift_push</span>(<span class="ident">new</span>);
<span class="kw">return</span> <span class="prelude-val">Some</span>(<span class="ident">last</span>.<span class="ident">clone</span>());
}
}
<span class="prelude-val">None</span>
}
}
<span class="kw">pub</span> <span class="kw">trait</span> <span class="ident">TupleCollect</span>: <span class="ident">Sized</span> {
<span class="kw">type</span> <span class="ident">Item</span>;
<span class="kw">type</span> <span class="ident">Buffer</span>: <span class="ident">Default</span> <span class="op">+</span> <span class="ident">AsRef</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="op">></span> <span class="op">+</span> <span class="ident">AsMut</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="op">></span>;
<span class="kw">fn</span> <span class="ident">collect_from_iter</span><span class="op"><</span><span class="ident">I</span><span class="op">></span>(<span class="ident">iter</span>: <span class="ident">I</span>, <span class="ident">buf</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">Self</span><span class="ident">::Buffer</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="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="self">Self</span><span class="ident">::Item</span><span class="op">></span>;
<span class="kw">fn</span> <span class="ident">collect_from_iter_no_buf</span><span class="op"><</span><span class="ident">I</span><span class="op">></span>(<span class="ident">iter</span>: <span class="ident">I</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="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="self">Self</span><span class="ident">::Item</span><span class="op">></span>;
<span class="kw">fn</span> <span class="ident">num_items</span>() <span class="op">-</span><span class="op">></span> <span class="ident">usize</span>;
<span class="kw">fn</span> <span class="ident">left_shift_push</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">item</span>: <span class="self">Self</span><span class="ident">::Item</span>);
}
<span class="macro">macro_rules!</span> <span class="ident">impl_tuple_collect</span> {
() <span class="op">=</span><span class="op">></span> ();
(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">N</span>:<span class="ident">expr</span>; <span class="macro-nonterminal">$</span><span class="macro-nonterminal">A</span>:<span class="ident">ident</span> ; $(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">X</span>:<span class="ident">ident</span>),<span class="op">*</span> ; $(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">Y</span>:<span class="ident">ident</span>),<span class="op">*</span> ; $(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">Y_rev</span>:<span class="ident">ident</span>),<span class="kw-2">*</span>) <span class="op">=</span><span class="op">></span> (
<span class="kw">impl</span><span class="op"><</span><span class="macro-nonterminal">$</span><span class="macro-nonterminal">A</span><span class="op">></span> <span class="ident">TupleCollect</span> <span class="kw">for</span> ($(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">X</span>),<span class="kw-2">*</span>,) {
<span class="kw">type</span> <span class="ident">Item</span> <span class="op">=</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">A</span>;
<span class="kw">type</span> <span class="ident">Buffer</span> <span class="op">=</span> [<span class="prelude-ty">Option</span><span class="op"><</span><span class="macro-nonterminal">$</span><span class="macro-nonterminal">A</span><span class="op">></span>; <span class="macro-nonterminal">$</span><span class="macro-nonterminal">N</span> <span class="op">-</span> <span class="number">1</span>];
<span class="attribute">#[<span class="ident">allow</span>(<span class="ident">unused_assignments</span>, <span class="ident">unused_mut</span>)]</span>
<span class="kw">fn</span> <span class="ident">collect_from_iter</span><span class="op"><</span><span class="ident">I</span><span class="op">></span>(<span class="ident">iter</span>: <span class="ident">I</span>, <span class="ident">buf</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">Self</span><span class="ident">::Buffer</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="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="macro-nonterminal">$</span><span class="macro-nonterminal">A</span><span class="op">></span>
{
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">iter</span> <span class="op">=</span> <span class="ident">iter</span>.<span class="ident">into_iter</span>();
$(
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">Y</span> <span class="op">=</span> <span class="prelude-val">None</span>;
)<span class="op">*</span>
<span class="kw">loop</span> {
$(
<span class="macro-nonterminal">$</span><span class="macro-nonterminal">Y</span> <span class="op">=</span> <span class="ident">iter</span>.<span class="ident">next</span>();
<span class="kw">if</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">Y</span>.<span class="ident">is_none</span>() {
<span class="kw">break</span>
}
)<span class="op">*</span>
<span class="kw">return</span> <span class="prelude-val">Some</span>(($(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">Y</span>.<span class="ident">unwrap</span>()),<span class="kw-2">*</span>,))
}
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">i</span> <span class="op">=</span> <span class="number">0</span>;
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">s</span> <span class="op">=</span> <span class="ident">buf</span>.<span class="ident">as_mut</span>();
$(
<span class="kw">if</span> <span class="ident">i</span> <span class="op"><</span> <span class="ident">s</span>.<span class="ident">len</span>() {
<span class="ident">s</span>[<span class="ident">i</span>] <span class="op">=</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">Y</span>;
<span class="ident">i</span> <span class="op">+</span><span class="op">=</span> <span class="number">1</span>;
}
)<span class="op">*</span>
<span class="kw">return</span> <span class="prelude-val">None</span>;
}
<span class="attribute">#[<span class="ident">allow</span>(<span class="ident">unused_assignments</span>)]</span>
<span class="kw">fn</span> <span class="ident">collect_from_iter_no_buf</span><span class="op"><</span><span class="ident">I</span><span class="op">></span>(<span class="ident">iter</span>: <span class="ident">I</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="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="macro-nonterminal">$</span><span class="macro-nonterminal">A</span><span class="op">></span>
{
<span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">iter</span> <span class="op">=</span> <span class="ident">iter</span>.<span class="ident">into_iter</span>();
<span class="kw">loop</span> {
$(
<span class="kw">let</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">Y</span> <span class="op">=</span> <span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">Y</span>) <span class="op">=</span> <span class="ident">iter</span>.<span class="ident">next</span>() {
<span class="macro-nonterminal">$</span><span class="macro-nonterminal">Y</span>
} <span class="kw">else</span> {
<span class="kw">break</span>;
};
)<span class="op">*</span>
<span class="kw">return</span> <span class="prelude-val">Some</span>(($(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">Y</span>),<span class="kw-2">*</span>,))
}
<span class="kw">return</span> <span class="prelude-val">None</span>;
}
<span class="kw">fn</span> <span class="ident">num_items</span>() <span class="op">-</span><span class="op">></span> <span class="ident">usize</span> {
<span class="macro-nonterminal">$</span><span class="macro-nonterminal">N</span>
}
<span class="kw">fn</span> <span class="ident">left_shift_push</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">item</span>: <span class="macro-nonterminal">$</span><span class="macro-nonterminal">A</span>) {
<span class="kw">use</span> <span class="ident">std::mem::replace</span>;
<span class="kw">let</span> <span class="kw-2">&</span><span class="kw-2">mut</span> ($(<span class="kw-2">ref</span> <span class="kw-2">mut</span> <span class="macro-nonterminal">$</span><span class="macro-nonterminal">Y</span>),<span class="kw-2">*</span>,) <span class="op">=</span> <span class="self">self</span>;
<span class="kw">let</span> <span class="ident">tmp</span> <span class="op">=</span> <span class="ident">item</span>;
$(
<span class="kw">let</span> <span class="ident">tmp</span> <span class="op">=</span> <span class="ident">replace</span>(<span class="macro-nonterminal">$</span><span class="macro-nonterminal">Y_rev</span>, <span class="ident">tmp</span>);
)<span class="op">*</span>
<span class="ident">drop</span>(<span class="ident">tmp</span>);
}
}
)
}
<span class="macro">impl_tuple_collect!</span>(<span class="number">1</span>; <span class="ident">A</span>; <span class="ident">A</span>; <span class="ident">a</span>; <span class="ident">a</span>);
<span class="macro">impl_tuple_collect!</span>(<span class="number">2</span>; <span class="ident">A</span>; <span class="ident">A</span>, <span class="ident">A</span>; <span class="ident">a</span>, <span class="ident">b</span>; <span class="ident">b</span>, <span class="ident">a</span>);
<span class="macro">impl_tuple_collect!</span>(<span class="number">3</span>; <span class="ident">A</span>; <span class="ident">A</span>, <span class="ident">A</span>, <span class="ident">A</span>; <span class="ident">a</span>, <span class="ident">b</span>, <span class="ident">c</span>; <span class="ident">c</span>, <span class="ident">b</span>, <span class="ident">a</span>);
<span class="macro">impl_tuple_collect!</span>(<span class="number">4</span>; <span class="ident">A</span>; <span class="ident">A</span>, <span class="ident">A</span>, <span class="ident">A</span>, <span class="ident">A</span>; <span class="ident">a</span>, <span class="ident">b</span>, <span class="ident">c</span>, <span class="ident">d</span>; <span class="ident">d</span>, <span class="ident">c</span>, <span class="ident">b</span>, <span class="ident">a</span>);
</pre></div>
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