forked from Orchid/orchid
Lawrence Bethlenfalvy
3c0056c2db
IO adapted to use it Also, Atoms can now dispatch type-erased requests
28 lines
816 B
Rust
28 lines
816 B
Rust
/// Utility functions to get rid of tedious explicit casts to
|
|
/// BoxedIter
|
|
use std::iter;
|
|
|
|
/// A trait object of [Iterator] to be assigned to variables that may be
|
|
/// initialized form multiple iterators of incompatible types
|
|
pub type BoxedIter<'a, T> = Box<dyn Iterator<Item = T> + 'a>;
|
|
/// creates a [BoxedIter] of a single element
|
|
pub fn box_once<'a, T: 'a>(t: T) -> BoxedIter<'a, T> {
|
|
Box::new(iter::once(t))
|
|
}
|
|
/// creates an empty [BoxedIter]
|
|
pub fn box_empty<'a, T: 'a>() -> BoxedIter<'a, T> {
|
|
Box::new(iter::empty())
|
|
}
|
|
|
|
/// Chain various iterators into a [BoxedIter]
|
|
macro_rules! box_chain {
|
|
($curr:expr) => {
|
|
Box::new($curr) as BoxedIter<_>
|
|
};
|
|
($curr:expr, $($rest:expr),*) => {
|
|
Box::new($curr$(.chain($rest))*) as $crate::utils::boxed_iter::BoxedIter<_>
|
|
};
|
|
}
|
|
|
|
pub(crate) use box_chain;
|