pub trait Functor: Kind_cdc7cd43dac7585f {
// Required method
fn map<'a, F, A: 'a, B: 'a>(
f: F,
fa: <Self as Kind_cdc7cd43dac7585f>::Of<'a, A>,
) -> <Self as Kind_cdc7cd43dac7585f>::Of<'a, B>
where F: Fn(A) -> B + 'a;
}Expand description
A type class for types that can be mapped over.
A Functor represents a context or container that allows functions to be applied
to values within that context without altering the structure of the context itself.
§Laws
Functor instances must satisfy the following laws:
- Identity:
map(identity, fa) = fa. - Composition:
map(compose(f, g), fa) = map(f, map(g, fa)).
Required Methods§
Sourcefn map<'a, F, A: 'a, B: 'a>(
f: F,
fa: <Self as Kind_cdc7cd43dac7585f>::Of<'a, A>,
) -> <Self as Kind_cdc7cd43dac7585f>::Of<'a, B>where
F: Fn(A) -> B + 'a,
fn map<'a, F, A: 'a, B: 'a>(
f: F,
fa: <Self as Kind_cdc7cd43dac7585f>::Of<'a, A>,
) -> <Self as Kind_cdc7cd43dac7585f>::Of<'a, B>where
F: Fn(A) -> B + 'a,
Maps a function over the values in the functor context.
This method applies a function to the value(s) inside the functor context, producing a new functor context with the transformed value(s).
§Type Signature
forall a b. Functor f => (a -> b, f a) -> f b
§Type Parameters
F: The type of the function to apply.A: The type of the value(s) inside the functor.B: The type of the result(s) of applying the function.
§Parameters
f: The function to apply to the value(s) inside the functor.fa: The functor instance containing the value(s).
§Returns
A new functor instance containing the result(s) of applying the function.
§Examples
use fp_library::classes::functor::Functor;
use fp_library::brands::OptionBrand;
let x = Some(5);
let y = OptionBrand::map(|i| i * 2, x);
assert_eq!(y, Some(10));Dyn Compatibility§
This trait is not dyn compatible.
In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.