1use crate::adaptors::map::{MapSpecialCase, MapSpecialCaseFn};
2
3macro_rules! impl_cons_iter(
4 ($_A:ident, $_B:ident, ) => (); // stop
5
6 ($A:ident, $($B:ident,)*) => (
7 impl_cons_iter!($($B,)*);
8 #[allow(non_snake_case)]
9 impl<$($B),*, X> MapSpecialCaseFn<(($($B,)*), X)> for ConsTuplesFn {
10 type Out = ($($B,)* X, );
11 fn call(&mut self, (($($B,)*), X): (($($B,)*), X)) -> Self::Out {
12 ($($B,)* X, )
13 }
14 }
15 );
16);
17
18impl_cons_iter!(A, B, C, D, E, F, G, H, I, J, K, L,);
19
20#[derive(Debug, Clone)]
21pub struct ConsTuplesFn;
22
23/// An iterator that maps an iterator of tuples like
24/// `((A, B), C)` to an iterator of `(A, B, C)`.
25///
26/// Used by the `iproduct!()` macro.
27pub type ConsTuples<I> = MapSpecialCase<I, ConsTuplesFn>;
28
29/// Create an iterator that maps for example iterators of
30/// `((A, B), C)` to `(A, B, C)`.
31pub fn cons_tuples<I>(iterable: I) -> ConsTuples<I::IntoIter>
32where
33 I: IntoIterator,
34{
35 ConsTuples {
36 iter: iterable.into_iter(),
37 f: ConsTuplesFn,
38 }
39}
40