Data.StackPrism.Generic

Documentation

type StackPrisms a = PrismList (Rep a) a

mkPrismList :: (Generic a, MkPrismList (Rep a)) => StackPrisms a

Derive a list of stack prisms, one for each constructor in the Generic datatype a. The list is wrapped in the unary constructor PrismList. Within that constructor, the prisms are separated by the right-associative binary infix constructor :&. Finally, the individual prisms are wrapped in the unary constructor I. These constructors are all exported by this module, but no documentation is generated for them by Hackage.

As an example, here is how to define the prisms nil and cons for [a], which is an instance of Generic:

 nil  :: StackPrism              t  ([a] :- t)
 cons :: StackPrism (a :- [a] :- t) ([a] :- t)
 PrismList (P nil :& P cons) = mkPrismList :: StackPrisms [a]

data family PrismList f a

type family StackPrismLhs f t :: *