Copyright	(c) 2018-2022 Kowainik
License	MPL-2.0
Maintainer	Kowainik <xrom.xkov@gmail.com>
Stability	Stable
Portability	Portable
Safe Haskell	Safe-Inferred
Language	Haskell2010

Toml.Codec.Types

Contents

Toml Codec
Toml Environment
Toml State
Codec
Function alternative

Description

Contains general underlying monad for bidirectional conversion.

Since: 1.3.0.0

Synopsis

type TomlCodec a = Codec a a
type TomlEnv a = TOML -> Validation [TomlDecodeError] a
newtype TomlState a = TomlState {
- unTomlState :: TOML -> (Maybe a, TOML)
}
eitherToTomlState :: Either e a -> TomlState a
data Codec i o = Codec {
- codecRead :: TomlEnv o
- codecWrite :: i -> TomlState o
}
(<!>) :: Alternative f => (a -> f x) -> (a -> f x) -> a -> f x

Toml Codec

type TomlCodec a = Codec a a Source #

Specialied Codec type alias for bidirectional TOML serialization. Keeps TOML object as both environment and state.

Since: 0.5.0

Toml Environment

type TomlEnv a = TOML -> Validation [TomlDecodeError] a Source #

Immutable environment for TOML conversion.

Since: 1.3.0.0

Toml State

newtype TomlState a Source #

Mutable context for TOML conversion. We are introducing our own implemetation of state with MonadState instance due to some limitation in the design connected to the usage of State.

This newtype is equivalent to the following transformer:

MaybeT (State TOML)

Since: 1.3.0.0

Constructors

TomlState
Fields unTomlState :: TOML -> (Maybe a, TOML)

Instances

Instances details

Alternative TomlState Source #	Since: 1.3.0.0
Instance details Defined in Toml.Codec.Types Methods empty :: TomlState a # (<\|>) :: TomlState a -> TomlState a -> TomlState a # some :: TomlState a -> TomlState [a] # many :: TomlState a -> TomlState [a] #
Applicative TomlState Source #	Since: 1.3.0.0
Instance details Defined in Toml.Codec.Types Methods pure :: a -> TomlState a # (<>) :: TomlState (a -> b) -> TomlState a -> TomlState b # liftA2 :: (a -> b -> c) -> TomlState a -> TomlState b -> TomlState c # (>) :: TomlState a -> TomlState b -> TomlState b # (<*) :: TomlState a -> TomlState b -> TomlState a #
Functor TomlState Source #	Since: 1.3.0.0
Instance details Defined in Toml.Codec.Types Methods fmap :: (a -> b) -> TomlState a -> TomlState b # (<$) :: a -> TomlState b -> TomlState a #
Monad TomlState Source #	Since: 1.3.0.0
Instance details Defined in Toml.Codec.Types Methods (>>=) :: TomlState a -> (a -> TomlState b) -> TomlState b # (>>) :: TomlState a -> TomlState b -> TomlState b # return :: a -> TomlState a #
s ~ TOML => MonadState s TomlState Source #	Since: 1.3.0.0
Instance details Defined in Toml.Codec.Types Methods get :: TomlState s # put :: s -> TomlState () # state :: (s -> (a, s)) -> TomlState a #

eitherToTomlState :: Either e a -> TomlState a Source #

Transform Either into TomlState.

Since: 1.3.0.0

Codec

data Codec i o Source #

Monad for bidirectional conversion. Contains pair of functions:

How to read value of type o (out) from immutable environment context (TomlEnv)?
How to store a value of type i (in) in stateful context (TomlState) and return a value of type o?

This approach with the bunch of utility functions allows to have single description for from/to TOML conversion.

In practice this type will always be used in the following way:

type TomlCodec a = Codec a a

Type parameter i if fictional. Here some trick is used. This trick is implemented in the codec package and described in more details in related blog post: https://blog.poisson.chat/posts/2016-10-12-bidirectional-serialization.html.

Since: 0.0.0

Constructors

Codec
Fields codecRead :: TomlEnv o Extract value of type `o` from monadic context `TomlEnv`. codecWrite :: i -> TomlState o Store value of type `i` inside monadic context `TomlState` and returning value of type `o`. Type of this function actually should be `o -> TomlState ()` but with such type it's impossible to have `Monad` and other instances.

Instances

Instances details

Alternative (Codec i) Source #
Instance details Defined in Toml.Codec.Types Methods empty :: Codec i a # (<\|>) :: Codec i a -> Codec i a -> Codec i a # some :: Codec i a -> Codec i [a] # many :: Codec i a -> Codec i [a] #
Applicative (Codec i) Source #	Since: 0.0.0
Instance details Defined in Toml.Codec.Types Methods pure :: a -> Codec i a # (<>) :: Codec i (a -> b) -> Codec i a -> Codec i b # liftA2 :: (a -> b -> c) -> Codec i a -> Codec i b -> Codec i c # (>) :: Codec i a -> Codec i b -> Codec i b # (<*) :: Codec i a -> Codec i b -> Codec i a #
Functor (Codec i) Source #	Since: 0.0.0
Instance details Defined in Toml.Codec.Types Methods fmap :: (a -> b) -> Codec i a -> Codec i b # (<$) :: a -> Codec i b -> Codec i a #

Function alternative

(<!>) :: Alternative f => (a -> f x) -> (a -> f x) -> a -> f x infixl 3 Source #

Alternative instance for function arrow but without empty.