Documentation

TypedSchemaFlex enc dec is a schema for encoding from enc and decoding to dec. Usually we want enc and dec to be the same type but this flexibility comes in handy for composition.

• introduction forms: record, enum, schema
• operations: encodeToWith, decodeFrom, extractSchema
• composition: dimap, union, stringMap, liftPrism

named n sc annotates a schema with a name, allowing for circular schemas.

enum values mapping construct a schema for a non empty set of values with a Text mapping

stringMap sc is the schema for a stringmap where the values have schema sc

list sc is the schema for a list of values with schema sc

vector sc is the schema for a vector of values with schema sc

viaJson label constructs a schema reusing existing aeson instances. The resulting schema is opaque and cannot be subtyped and/or versioned, so this constructor should be used sparingly. The label is used to describe the extracted Schema.

Apply an isomorphism to a schema

The schema of String values

A schema for types that can be parsed and pretty-printed. The resulting schema is opaque and cannot be subtyped/versioned, so this constructor is best used for primitive value

The schema of undiscriminated unions. Prefer using union where possible

Lens for the fieldName attribute

An Alternative profunctor for defining record schemas with versioning

 schemaPerson = Person
            <$> (field "name" name <|> field "full name" name)
            <*> (field "age" age <|> pure -1)

Map a function over all the field names

Wrap an applicative record schema

fieldWith sc n get introduces a field

Generalised version of fieldWith

Project a schema through a Prism. Returns a partial schema. When encoding/decoding a value that doesn't fit the prism, an optional field will be omitted, and a required field will cause this alternative to be aborted.

liftJust = liftPrism _Just

liftRight = liftPrism _Right

A generalized version of optField. Does not handle infinite/circular data.

The most general introduction form for optional alts

A generalized version of optFieldEither. Does not handle infinite/circular data

The schema of discriminated unions

  import Schemas
  import "generic-lens" Data.Generics.Labels ()
  import GHC.Generics

  data Education = Degree Text | PhD Text | NoEducation

  schemaEducation = union'
    [ alt "NoEducation" #_NoEducation
    , alt "Degree"      #_Degree
    , alt "PhD"         #_PhD
    ]
  

Given a non empty set of tagged partial schemas, constructs the schema that applies them in order and selects the first successful match.

Existential wrapper for convenient definition of discriminated unions

altWith name prism schema introduces a discriminated union alternative

Given a non empty set of constructors, construct the schema that selects the first matching constructor

Extract an untyped schema that can be serialized.

For schemas with alternatives, this enumerates all the possible versions lazily. Beware when using on schemas with multiple alternatives, as the number of versions is exponential.

Extract all the field groups (from alternatives) in the record

Returns all the primitive validators embedded in this typed schema

Given a typed schema, produce a JSON encoder to the firt version returned by extractSchema

Given source and target schemas, produce a JSON encoder

Runs a schema as a function enc -> dec. Loops for infinite/circular data

Given a JSON Value and a typed schema, extract a Haskell value