Safe Haskell	None
Language	Haskell2010

Data.Codec.Field

Contents

First-class record construction

Synopsis

First-class record construction

data Field r a x y Source

Describes how to apply a constructor argument and how to extract from a record. y should be x with one argument knocked out: e. g.

Field MyType Int (Int -> a2 -> MyType) (X -> a2 -> MyType)

Constructors

Field (a -> x -> y) (r -> a)

newtype Build r f x y Source

An ongoing record construction of an r in context f. Applicative actions are sequenced in the direction of >>>.

Constructors

Build (f (x -> y))

Instances

Applicative f => Category * (Build r f)

data Con r x Source

A constructor for a given record and a way to check whether it has it.

Constructors

Con x (r -> Bool)

($>>) :: (Functor f, Buildable r y) => x -> Build r f x y -> f r infixr 1 Source

Infix version of build.

(>>>) :: Category k cat => cat a b -> cat b c -> cat a c infixr 1

Left-to-right composition

done :: Applicative f => Build r f x x Source

No-op Build (same as id).

data X Source

Fields partially apply constructors and replace arguments with this type.

Constructors

X

Instances

Buildable r b => Buildable r (X -> b)
Field2 (a, b) b (a1 -> b -> (a, b)) (a1 -> X -> (a, b))
Field1 (a, b) a (a -> a2 -> (a, b)) (X -> a2 -> (a, b))

class Buildable r a where Source

The class of constructor applications that have been completely filled in by composing Builds. If you see an error message involving this, it means that you forgot to specify a Build for a field.

Methods

give :: a -> r Source

Instances

Buildable r r
Buildable r b => Buildable r (X -> b)

having :: Functor f => Field r a x y -> f a -> Build r f x y Source

Combine a Field and a way to produce an a to get a Build.

build :: (Functor f, Buildable r y) => x -> Build r f x y -> f r Source

Finish a construction given a constructor.