38 lines
953 B
Rust
38 lines
953 B
Rust
/// Utility functions to get rid of explicit casts to BoxedIter which are tedious
|
|
|
|
use std::iter;
|
|
|
|
pub type BoxedIter<'a, T> = Box<dyn Iterator<Item = T> + 'a>;
|
|
pub type BoxedIterIter<'a, T> = BoxedIter<'a, BoxedIter<'a, T>>;
|
|
/// BoxedIter of a single element
|
|
pub fn box_once<'a, T: 'a>(t: T) -> BoxedIter<'a, T> {
|
|
Box::new(iter::once(t))
|
|
}
|
|
/// BoxedIter of no elements
|
|
pub fn box_empty<'a, T: 'a>() -> BoxedIter<'a, T> {
|
|
Box::new(iter::empty())
|
|
}
|
|
|
|
#[macro_export]
|
|
macro_rules! box_chain {
|
|
($curr:expr) => {
|
|
Box::new($curr) as BoxedIter<_>
|
|
};
|
|
($curr:expr, $($rest:expr),*) => {
|
|
Box::new($curr$(.chain($rest))*) as $crate::utils::iter::BoxedIter<_>
|
|
};
|
|
}
|
|
|
|
pub fn box_flatten<'a,
|
|
T: 'a,
|
|
I: 'a + Iterator<Item = J>,
|
|
J: 'a + Iterator<Item = T>
|
|
>(i: I) -> BoxedIter<'a, T> {
|
|
Box::new(i.flatten())
|
|
}
|
|
|
|
pub fn into_boxed_iter<'a,
|
|
T: 'a + IntoIterator
|
|
>(t: T) -> BoxedIter<'a, <T as IntoIterator>::Item> {
|
|
Box::new(t.into_iter())
|
|
} |