use std::rc::Rc;
pub trait Bind {
type Elm;
type M<B>;
fn bind<B, F>(self, f: F) -> Self::M<B>
where
F: Fn(&Self::Elm) -> Self::M<B>;
}
macro_rules! bind_numeric_impl {
($($t:ty)*) => ($(
impl Bind for $t {
type Elm = $t;
type M<U> = U;
fn bind<B, F>(self, f: F) -> Self::M<B>
where
F: Fn(&Self::Elm) -> Self::M<B>,
{
f(&self)
}
}
)*)
}
bind_numeric_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 f32 f64 }
impl<A> Bind for Rc<A> {
type Elm = A;
type M<U> = Rc<U>;
fn bind<B, F>(self, f: F) -> Self::M<B>
where
F: FnOnce(&Self::Elm) -> Self::M<B>,
{
f(&self)
}
}
impl<A> Bind for Box<A> {
type Elm = A;
type M<U> = Box<U>;
fn bind<B, F>(self, f: F) -> Self::M<B>
where
F: FnOnce(&Self::Elm) -> Self::M<B>,
{
f(&self)
}
}
impl<A> Bind for Option<A> {
type Elm = A;
type M<U> = Option<U>;
fn bind<B, F>(self, f: F) -> Self::M<B>
where
F: FnOnce(&Self::Elm) -> Self::M<B>,
{
self.and_then(|e| f(&e))
}
}
impl<A, E: Clone> Bind for Result<A, E> {
type Elm = A;
type M<U> = Result<U, E>;
fn bind<B, F>(self, f: F) -> Self::M<B>
where
F: FnOnce(&Self::Elm) -> Self::M<B>,
{
self.and_then(|e| f(&e))
}
}
impl<A> Bind for Vec<A> {
type Elm = A;
type M<U> = Vec<U>;
fn bind<B, F>(self, f: F) -> Self::M<B>
where
F: Fn(&Self::Elm) -> Self::M<B>,
{
self.iter().flat_map(f).collect()
}
}