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Diffstat (limited to 'vendor/itertools/src/either_or_both.rs')
| -rw-r--r-- | vendor/itertools/src/either_or_both.rs | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/vendor/itertools/src/either_or_both.rs b/vendor/itertools/src/either_or_both.rs new file mode 100644 index 000000000..28d1df757 --- /dev/null +++ b/vendor/itertools/src/either_or_both.rs @@ -0,0 +1,205 @@ +use crate::EitherOrBoth::*; + +use either::Either; + +/// Value that either holds a single A or B, or both. +#[derive(Clone, PartialEq, Eq, Hash, Debug)] +pub enum EitherOrBoth<A, B> { + /// Both values are present. + Both(A, B), + /// Only the left value of type `A` is present. + Left(A), + /// Only the right value of type `B` is present. + Right(B), +} + +impl<A, B> EitherOrBoth<A, B> { + /// If `Left`, or `Both`, return true, otherwise, return false. + pub fn has_left(&self) -> bool { + self.as_ref().left().is_some() + } + + /// If `Right`, or `Both`, return true, otherwise, return false. + pub fn has_right(&self) -> bool { + self.as_ref().right().is_some() + } + + /// If Left, return true otherwise, return false. + /// Exclusive version of [`has_left`](EitherOrBoth::has_left). + pub fn is_left(&self) -> bool { + match *self { + Left(_) => true, + _ => false, + } + } + + /// If Right, return true otherwise, return false. + /// Exclusive version of [`has_right`](EitherOrBoth::has_right). + pub fn is_right(&self) -> bool { + match *self { + Right(_) => true, + _ => false, + } + } + + /// If Right, return true otherwise, return false. + /// Equivalent to `self.as_ref().both().is_some()`. + pub fn is_both(&self) -> bool { + self.as_ref().both().is_some() + } + + /// If `Left`, or `Both`, return `Some` with the left value, otherwise, return `None`. + pub fn left(self) -> Option<A> { + match self { + Left(left) | Both(left, _) => Some(left), + _ => None, + } + } + + /// If `Right`, or `Both`, return `Some` with the right value, otherwise, return `None`. + pub fn right(self) -> Option<B> { + match self { + Right(right) | Both(_, right) => Some(right), + _ => None, + } + } + + /// If Both, return `Some` tuple containing left and right. + pub fn both(self) -> Option<(A, B)> { + match self { + Both(a, b) => Some((a, b)), + _ => None, + } + } + + /// Converts from `&EitherOrBoth<A, B>` to `EitherOrBoth<&A, &B>`. + pub fn as_ref(&self) -> EitherOrBoth<&A, &B> { + match *self { + Left(ref left) => Left(left), + Right(ref right) => Right(right), + Both(ref left, ref right) => Both(left, right), + } + } + + /// Converts from `&mut EitherOrBoth<A, B>` to `EitherOrBoth<&mut A, &mut B>`. + pub fn as_mut(&mut self) -> EitherOrBoth<&mut A, &mut B> { + match *self { + Left(ref mut left) => Left(left), + Right(ref mut right) => Right(right), + Both(ref mut left, ref mut right) => Both(left, right), + } + } + + /// Convert `EitherOrBoth<A, B>` to `EitherOrBoth<B, A>`. + pub fn flip(self) -> EitherOrBoth<B, A> { + match self { + Left(a) => Right(a), + Right(b) => Left(b), + Both(a, b) => Both(b, a), + } + } + + /// Apply the function `f` on the value `a` in `Left(a)` or `Both(a, b)` variants. If it is + /// present rewrapping the result in `self`'s original variant. + pub fn map_left<F, M>(self, f: F) -> EitherOrBoth<M, B> + where + F: FnOnce(A) -> M, + { + match self { + Both(a, b) => Both(f(a), b), + Left(a) => Left(f(a)), + Right(b) => Right(b), + } + } + + /// Apply the function `f` on the value `b` in `Right(b)` or `Both(a, b)` variants. + /// If it is present rewrapping the result in `self`'s original variant. + pub fn map_right<F, M>(self, f: F) -> EitherOrBoth<A, M> + where + F: FnOnce(B) -> M, + { + match self { + Left(a) => Left(a), + Right(b) => Right(f(b)), + Both(a, b) => Both(a, f(b)), + } + } + + /// Apply the functions `f` and `g` on the value `a` and `b` respectively; + /// found in `Left(a)`, `Right(b)`, or `Both(a, b)` variants. + /// The Result is rewrapped `self`'s original variant. + pub fn map_any<F, L, G, R>(self, f: F, g: G) -> EitherOrBoth<L, R> + where + F: FnOnce(A) -> L, + G: FnOnce(B) -> R, + { + match self { + Left(a) => Left(f(a)), + Right(b) => Right(g(b)), + Both(a, b) => Both(f(a), g(b)), + } + } + + /// Apply the function `f` on the value `a` in `Left(a)` or `Both(a, _)` variants if it is + /// present. + pub fn left_and_then<F, L>(self, f: F) -> EitherOrBoth<L, B> + where + F: FnOnce(A) -> EitherOrBoth<L, B>, + { + match self { + Left(a) | Both(a, _) => f(a), + Right(b) => Right(b), + } + } + + /// Apply the function `f` on the value `b` + /// in `Right(b)` or `Both(_, b)` variants if it is present. + pub fn right_and_then<F, R>(self, f: F) -> EitherOrBoth<A, R> + where + F: FnOnce(B) -> EitherOrBoth<A, R>, + { + match self { + Left(a) => Left(a), + Right(b) | Both(_, b) => f(b), + } + } + + /// Returns a tuple consisting of the `l` and `r` in `Both(l, r)`, if present. + /// Otherwise, returns the wrapped value for the present element, and the [`default`](Default::default) + /// for the other. + pub fn or_default(self) -> (A, B) + where + A: Default, + B: Default, + { + match self { + EitherOrBoth::Left(l) => (l, B::default()), + EitherOrBoth::Right(r) => (A::default(), r), + EitherOrBoth::Both(l, r) => (l, r), + } + } +} + +impl<T> EitherOrBoth<T, T> { + /// Return either value of left, right, or the product of `f` applied where `Both` are present. + pub fn reduce<F>(self, f: F) -> T + where + F: FnOnce(T, T) -> T, + { + match self { + Left(a) => a, + Right(b) => b, + Both(a, b) => f(a, b), + } + } +} + +impl<A, B> Into<Option<Either<A, B>>> for EitherOrBoth<A, B> { + fn into(self) -> Option<Either<A, B>> { + match self { + EitherOrBoth::Left(l) => Some(Either::Left(l)), + EitherOrBoth::Right(r) => Some(Either::Right(r)), + _ => None, + } + } +} |