The composition of Contravariant F and G, [x]F[G[x]]
, is
covariant.
The composition of Contravariant F and Functor G, [x]F[G[x]]
,
is contravariant.
The product of Contravariant F
and G
, [x](F[x], G[x]])
, is
contravariant.
Converts ma
to a value of type F[B]
using the provided functions f
and g
.
Converts ma
to a value of type F[B]
using the provided functions f
and g
.
Converts ma
to a value of type F[B]
using the provided bijection.
Converts ma
to a value of type F[B]
using the provided bijection.
Converts ma
to a value of type F[B]
using the provided isomorphism.
Converts ma
to a value of type F[B]
using the provided isomorphism.
Contravariant functors. For example, functions provide a Functor in their result type, but a Contravariant for each argument type.
Note that the dual of a Functor is just a Functor itself.
Providing an instance of this is a useful alternative to marking a type parameter with
-
in Scala.ContravariantLaw