Module

Type.Data.Row

Package
purescript-prelude
Repository
purescript/purescript-prelude

#RProxy Source

data RProxy (row :: # Type)

A proxy data type whose type parameter is a type of kind # Type (a row of types).

Commonly used for specialising a function with a quantified type. For example, suppose we have an identity function for records of type:

recordIdentity :: forall row . RProxy row -> Record row -> Record row
recordIdentity _ rec = rec

Then applying this function to an RProxy with a specialised type allows us to specify a concrete type for row:

:t recordIdentity (RProxy :: RProxy ( x :: Int, y :: Int ))
{ x :: Int, y :: Int } -> { x :: Int, y :: Int }

Here row has been specialised to ( x :: Int, y :: Int ).

Constructors