| 1 | macro_rules! impl_cons_iter( |
| 2 | ($_A:ident, $_B:ident, ) => (); // stop |
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| 3 | |
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| 4 | ($A:ident, $($B:ident,)*) => ( |
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| 5 | impl_cons_iter!($($B,)*); |
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| 6 | #[allow(non_snake_case)] |
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| 7 | impl<X, Iter, $($B),*> Iterator for ConsTuples<Iter, (($($B,)*), X)> |
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| 8 | where Iter: Iterator<Item = (($($B,)*), X)>, |
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| 9 | { |
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| 10 | type Item = ($($B,)* X, ); |
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| 11 | fn next(&mut self) -> Option<Self::Item> { |
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| 12 | self.iter.next().map(|(($($B,)*), x)| ($($B,)* x, )) |
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| 13 | } |
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| 14 | |
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| 15 | fn size_hint(&self) -> (usize, Option<usize>) { |
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| 16 | self.iter.size_hint() |
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| 17 | } |
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| 18 | fn fold<Acc, Fold>(self, accum: Acc, mut f: Fold) -> Acc |
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| 19 | where Fold: FnMut(Acc, Self::Item) -> Acc, |
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| 20 | { |
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| 21 | self.iter.fold(accum, move |acc, (($($B,)*), x)| f(acc, ($($B,)* x, ))) |
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| 22 | } |
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| 23 | } |
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| 24 | |
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| 25 | #[allow(non_snake_case)] |
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| 26 | impl<X, Iter, $($B),*> DoubleEndedIterator for ConsTuples<Iter, (($($B,)*), X)> |
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| 27 | where Iter: DoubleEndedIterator<Item = (($($B,)*), X)>, |
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| 28 | { |
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| 29 | fn next_back(&mut self) -> Option<Self::Item> { |
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| 30 | self.iter.next().map(|(($($B,)*), x)| ($($B,)* x, )) |
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| 31 | } |
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| 32 | } |
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| 33 | |
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| 34 | ); |
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| 35 | ); |
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| 36 | |
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| 37 | impl_cons_iter!(A, B, C, D, E, F, G, H, I, J, K, L,); |
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| 38 | |
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| 39 | /// An iterator that maps an iterator of tuples like |
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| 40 | /// `((A, B), C)` to an iterator of `(A, B, C)`. |
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| 41 | /// |
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| 42 | /// Used by the `iproduct!()` macro. |
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| 43 | #[must_use = "iterator adaptors are lazy and do nothing unless consumed" ] |
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| 44 | #[derive (Debug)] |
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| 45 | pub struct ConsTuples<I, J> |
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| 46 | where |
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| 47 | I: Iterator<Item = J>, |
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| 48 | { |
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| 49 | iter: I, |
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| 50 | } |
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| 51 | |
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| 52 | impl<I, J> Clone for ConsTuples<I, J> |
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| 53 | where |
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| 54 | I: Clone + Iterator<Item = J>, |
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| 55 | { |
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| 56 | clone_fields!(iter); |
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| 57 | } |
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| 58 | |
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| 59 | /// Create an iterator that maps for example iterators of |
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| 60 | /// `((A, B), C)` to `(A, B, C)`. |
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| 61 | pub fn cons_tuples<I, J>(iterable: I) -> ConsTuples<I::IntoIter, J> |
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| 62 | where |
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| 63 | I: IntoIterator<Item = J>, |
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| 64 | { |
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| 65 | ConsTuples { |
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| 66 | iter: iterable.into_iter(), |
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| 67 | } |
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| 68 | } |
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| 69 | |
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