Safe Haskell	Safe-Inferred
Language	Haskell2010

Data.Barbie.Bare

Contents

Description

Deprecated: Use Barbies.Bare

Synopsis

type family Wear t f a where ...
data Bare
data Covered
class FunctorB (b Covered) => BareB b where
- bstrip :: b Covered Identity -> b Bare Identity
- bcover :: b Bare Identity -> b Covered Identity
bstripFrom :: BareB b => (forall a. f a -> a) -> b Covered f -> b Bare Identity
bcoverWith :: BareB b => (forall a. a -> f a) -> b Bare Identity -> b Covered f

Bare values

type family Wear t f a where ... Source #

The Wear type-function allows one to define a Barbie-type as

data B t f
  = B { f1 :: Wear t f Int
      , f2 :: Wear t f Bool
      }

This gives rise to two rather different types:

B Covered f is a normal Barbie-type, in the sense that f1 :: B Covered f -> f Int, etc.
B Bare f, on the other hand, is a normal record with no functor around the type:

B { f1 :: 5, f2 = True } :: B Bare f

Equations

Wear Bare f a = a
Wear Covered f a = f a
Wear (Param _ t) f a = Wear t f a
Wear t _ _ = TypeError (('Text "`Wear` should only be used with " ':<>: 'Text "`Bare` or `Covered`.") ':$$: ((('Text "`" ':<>: 'ShowType t) ':<>: 'Text "`") ':<>: 'Text " is not allowed in this context."))

Covering and stripping

Class of Barbie-types defined using Wear and can therefore have Bare versions. Must satisfy:

bcover . bstrip = id
bstrip . bcover = id

Minimal complete definition

Nothing

Methods

bstripFrom :: BareB b => (forall a. f a -> a) -> b Covered f -> b Bare Identity Source #

Generalization of bstrip to arbitrary functors

bcoverWith :: BareB b => (forall a. a -> f a) -> b Bare Identity -> b Covered f Source #

Generalization of bcover to arbitrary functors