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Diffstat (limited to 'vendor/generic-array-0.12.4/src/functional.rs')
-rw-r--r-- | vendor/generic-array-0.12.4/src/functional.rs | 94 |
1 files changed, 94 insertions, 0 deletions
diff --git a/vendor/generic-array-0.12.4/src/functional.rs b/vendor/generic-array-0.12.4/src/functional.rs new file mode 100644 index 000000000..50f4a71b8 --- /dev/null +++ b/vendor/generic-array-0.12.4/src/functional.rs @@ -0,0 +1,94 @@ +//! Functional programming with generic sequences +//! +//! Please see `tests/generics.rs` for examples of how to best use these in your generic functions. + +use super::ArrayLength; +use core::iter::FromIterator; +use sequence::*; + +/// Defines the relationship between one generic sequence and another, +/// for operations such as `map` and `zip`. +pub unsafe trait MappedGenericSequence<T, U>: GenericSequence<T> +where + Self::Length: ArrayLength<U>, +{ + /// Mapped sequence type + type Mapped: GenericSequence<U, Length = Self::Length>; +} + +unsafe impl<'a, T, U, S: MappedGenericSequence<T, U>> MappedGenericSequence<T, U> for &'a S +where + &'a S: GenericSequence<T>, + S: GenericSequence<T, Length = <&'a S as GenericSequence<T>>::Length>, + <S as GenericSequence<T>>::Length: ArrayLength<U>, +{ + type Mapped = <S as MappedGenericSequence<T, U>>::Mapped; +} + +unsafe impl<'a, T, U, S: MappedGenericSequence<T, U>> MappedGenericSequence<T, U> for &'a mut S +where + &'a mut S: GenericSequence<T>, + S: GenericSequence<T, Length = <&'a mut S as GenericSequence<T>>::Length>, + <S as GenericSequence<T>>::Length: ArrayLength<U>, +{ + type Mapped = <S as MappedGenericSequence<T, U>>::Mapped; +} + +/// Accessor type for a mapped generic sequence +pub type MappedSequence<S, T, U> = + <<S as MappedGenericSequence<T, U>>::Mapped as GenericSequence<U>>::Sequence; + +/// Defines functional programming methods for generic sequences +pub unsafe trait FunctionalSequence<T>: GenericSequence<T> { + /// Maps a `GenericSequence` to another `GenericSequence`. + /// + /// If the mapping function panics, any already initialized elements in the new sequence + /// will be dropped, AND any unused elements in the source sequence will also be dropped. + fn map<U, F>(self, f: F) -> MappedSequence<Self, T, U> + where + Self: MappedGenericSequence<T, U>, + Self::Length: ArrayLength<U>, + F: FnMut(Self::Item) -> U, + { + FromIterator::from_iter(self.into_iter().map(f)) + } + + /// Combines two `GenericSequence` instances and iterates through both of them, + /// initializing a new `GenericSequence` with the result of the zipped mapping function. + /// + /// If the mapping function panics, any already initialized elements in the new sequence + /// will be dropped, AND any unused elements in the source sequences will also be dropped. + #[inline] + fn zip<B, Rhs, U, F>(self, rhs: Rhs, f: F) -> MappedSequence<Self, T, U> + where + Self: MappedGenericSequence<T, U>, + Rhs: MappedGenericSequence<B, U, Mapped = MappedSequence<Self, T, U>>, + Self::Length: ArrayLength<B> + ArrayLength<U>, + Rhs: GenericSequence<B, Length = Self::Length>, + F: FnMut(Self::Item, Rhs::Item) -> U, + { + rhs.inverted_zip2(self, f) + } + + /// Folds (or reduces) a sequence of data into a single value. + /// + /// If the fold function panics, any unused elements will be dropped. + fn fold<U, F>(self, init: U, f: F) -> U + where + F: FnMut(U, Self::Item) -> U, + { + self.into_iter().fold(init, f) + } +} + +unsafe impl<'a, T, S: GenericSequence<T>> FunctionalSequence<T> for &'a S +where + &'a S: GenericSequence<T>, +{ +} + +unsafe impl<'a, T, S: GenericSequence<T>> FunctionalSequence<T> for &'a mut S +where + &'a mut S: GenericSequence<T>, +{ +} |