Safe Haskell | Safe |
---|---|
Language | Haskell2010 |
- to :: (Profunctor p, Functor f, Contravariant f) => (s -> a) -> Optic' p f s a
- module Control.Lens
Documentation
to :: (Profunctor p, Functor f, Contravariant f) => (s -> a) -> Optic' p f s a Source #
Build an (index-preserving) Getter
from an arbitrary Haskell function.
See Control.Lens.to
for details.
In lens-4.14, the constraint
is missing from the definition of Functor
fto
. When compiling
with GHC 8.0, this leads to warnings for definitions like
foo :: Getter Bar Foo foo = to fooFromBar
because of the redundant
constraint. This definition is
identical to Control.Lens.Functor
fto
except for the additional constraint
.Functor
f
module Control.Lens