Data.Row.Switch

This module provides the ability to discharge a polymorphic variant using a record that has matching fields.

Documentation

class AppliesTo r f x | r x -> f, f r -> x where

A simple class that we use to provide a constraint for function application.

Methods

applyTo :: f -> x -> r

Instances

AppliesTo r (x -> r) x

Defined in Data.Row.Switch

Methods

applyTo :: (x -> r) -> x -> r

switch :: forall v r x. BiForall r v (AppliesTo x) => Var v -> Rec r -> x

A Var and a Rec can combine if their rows line up properly. Given a Variant along with a Record of functions from each possible value of the variant to a single output type, apply the correct function to the value in the variant.

caseon :: forall v r x. BiForall r v (AppliesTo x) => Rec r -> Var v -> x

The same as switch but with the argument order reversed