Mu.Schema.Optics

This module provides instances of LabelOptic to be used in conjunction with the optics package. In particular, there are two kind of optics to access different parts of a Term:

• With #field you obtain the lens (that is, a getter and a setter) for the corresponding field in a record.
• With #choice you obtain the prism for the desired choice in an enumeration. You can use then review to construct a term with the value.

In addition, we provide a utility function record to build a record out of the inner values. We intend the interface to be very simple, so this function is overloaded to take tuples of different size, with as many components as values in the schema type.

Build a term

record :: BuildRecord sch args r => r -> Term sch ('DRecord name args)

Build a Mu record Term from a tuple of its values.

Note: if the record has exactly _one_ field, you must use record1 instead.

record1 :: TypeLabel sch t1 r1 => r1 -> Term sch ('DRecord name '['FieldDef x1 t1])

Build a Mu record Term with exactly one field.

enum :: forall (choiceName :: Symbol) choices sch name. EnumLabel choices choiceName => Term sch ('DEnum name choices)

Build a Mu enumeration Term from the name of the choice.

_U0 :: forall (sch :: Schema') x xs r. TypeLabel sch x r => Prism' (NS (FieldValue sch) (x ': xs)) r

Prism to access the first choice of a union.

_Next :: forall (sch :: Schema') x xs. Prism' (NS (FieldValue sch) (x ': xs)) (NS (FieldValue sch) xs)

Prism to access all other choices of a union except for the first. Intended to use be used iteratively until you reach the desired choice with _U0.

_Next % _Next % _U0  -- access third choice

_U1 :: forall (sch :: Schema') a b xs r. TypeLabel sch b r => Prism' (NS (FieldValue sch) (a ': (b ': xs))) r

Prism to access the second choice of a union.

_U2 :: forall (sch :: Schema') a b c xs r. TypeLabel sch c r => Prism' (NS (FieldValue sch) (a ': (b ': (c ': xs)))) r

Prism to access the third choice of a union.

_U3 :: forall (sch :: Schema') a b c d xs r. TypeLabel sch d r => Prism' (NS (FieldValue sch) (a ': (b ': (c ': (d ': xs))))) r

Prism to access the fourth choice of a union.

Re-exported for convenience.

module Optics.Core

Additional utilities.

is :: Is k An_AffineFold => s -> Optic' k is s a -> Bool

Orphan instances

(EnumLabel choices choiceName, r ~ ()) => LabelOptic choiceName A_Prism (Term sch ('DEnum name choices :: TypeDefB Type typeName Symbol)) (Term sch ('DEnum name choices :: TypeDefB Type typeName Symbol)) r r

Methods

labelOptic :: Optic A_Prism NoIx (Term sch ('DEnum name choices)) (Term sch ('DEnum name choices)) r r

FieldLabel sch args fieldName r => LabelOptic fieldName A_Lens (Term sch ('DRecord name args)) (Term sch ('DRecord name args)) r r

Methods

labelOptic :: Optic A_Lens NoIx (Term sch ('DRecord name args)) (Term sch ('DRecord name args)) r r