Data.The

Description

Synopsis

Documentation

class The d a | d -> a where #

A class for extracing "the" underlying value. the should ideally be a coercion from some newtype wrap of a back to a.

For this common use case, in the module where newtype New a = New a is defined, an instance of The can be created with an empty definition:

newtype New a = New a
instance The (New a) a

Methods

the :: d -> a #

the :: Coercible d a => d -> a #

Instances

The (Named name a) a #
Instance details Defined in Theory.Named Methods the :: Named name a -> a #
The (Satisfies p a) a #
Instance details Defined in Data.Refined Methods the :: Satisfies p a -> a #
The a' a => The (a' ::: p) a #
Instance details Defined in Data.Refined Methods the :: (a' ::: p) -> a #

pattern The :: The d a => a -> d #

A view pattern for discarding the wrapper around a value.

f (The x) = expression x

is equivalent to

f x = let x' = the x in expression x'