coerce package:optics-core

This module defines operations to coerce the type parameters of optics to a representationally equal type. For example, if we have

newtype MkInt = MkInt Int

and

l :: Lens' S Int

then

coerceA @Int @MkInt l :: Lens' S MkInt

Lift coerce to the a parameter of an optic.

Lift coerce to the b parameter of an optic.

Lift coerce to the s parameter of an optic.

Lift coerce to the t parameter of an optic.

Data types that are representationally equal are isomorphic.

>>> view coerced 'x' :: Identity Char
Identity 'x'

Special case of coerced for trivial newtype wrappers.

>>> over (coerced1 @Identity) (++ "bar") (Identity "foo")
Identity "foobar"

Type-preserving version of coerced with type parameters rearranged for TypeApplications.

>>> newtype MkInt = MkInt Int deriving Show

>>> over (coercedTo @Int) (*3) (MkInt 2)
MkInt 6