Module

Foreign.Generic.Class

Package: purescript-foreign-generic
Repository: paf31/purescript-foreign-generic

#Options Source

type Options = { fieldTransform :: String -> String, sumEncoding :: SumEncoding, unwrapSingleArguments :: Boolean, unwrapSingleConstructors :: Boolean }

Encoding/Decoding options which can be used to customize Decode and Encode instances which are derived via Generic (see genericEncode and genericDecode).

#SumEncoding Source

data SumEncoding

The encoding of sum types for your type. TaggedObjects will be encoded in the form { [tagFieldName]: "ConstructorTag", [contentsFieldName]: "Contents"}. constructorTagTransform can be provided to transform the constructor tag to a form you use, e.g. toLower/toUpper.

Constructors

TaggedObject { constructorTagTransform :: String -> String, contentsFieldName :: String, tagFieldName :: String }

#defaultOptions Source

defaultOptions :: Options

Default decoding/encoding options:

Represent sum types as records with tag and contents fields
Unwrap single arguments
Don't unwrap single constructors
Use the constructor names as-is
Use the field names as-is

#Decode Source

class Decode a  where

The Decode class is used to generate decoding functions of the form Foreign -> F a using generics-rep deriving.

First, derive Generic for your data:

import Data.Generic.Rep

data MyType = MyType ...

derive instance genericMyType :: Generic MyType _

You can then use the genericDecode and genericDecodeJSON functions to decode your foreign/JSON-encoded data.

Members

decode :: Foreign -> F a

Instances

Decode Void
Decode Unit
Decode Foreign
Decode String
Decode Char
Decode Boolean
Decode Number
Decode Int
(Decode a) => Decode (Identity a)
(Decode a) => Decode (Array a)
(Decode a) => Decode (Maybe a)
(Decode v) => Decode (Object v)
(RowToList r rl, DecodeRecord r rl) => Decode (Record r)

#Encode Source

class Encode a  where

The Encode class is used to generate encoding functions of the form a -> Foreign using generics-rep deriving.

First, derive Generic for your data:

import Data.Generic.Rep

data MyType = MyType ...

derive instance genericMyType :: Generic MyType _

You can then use the genericEncode and genericEncodeJSON functions to encode your data as JSON.

Members

encode :: a -> Foreign

Instances

Encode Void
Encode Unit
Encode Foreign
Encode String
Encode Char
Encode Boolean
Encode Number
Encode Int
(Encode a) => Encode (Identity a)
(Encode a) => Encode (Array a)
(Encode a) => Encode (Maybe a)
(Encode v) => Encode (Object v)
(RowToList r rl, EncodeRecord r rl) => Encode (Record r)

#DecodeWithOptions Source

class DecodeWithOptions a  where

When deriving En/Decode instances using Generic, we want the Options object to apply to the outermost record type(s) under the data constructors.

For this reason, we cannot use En/Decode directly when we reach an Argument during generic traversal of a type, because it might be a record type. Instead, we need to peel off any record type(s) and apply the appropriate Options before we can delegate to En/Decode, which can bake in its own Options.