tomland-1.3.3.3: Bidirectional TOML serialization
Copyright(c) 2018-2022 Kowainik
LicenseMPL-2.0
MaintainerKowainik <xrom.xkov@gmail.com>
StabilityStable
PortabilityPortable
Safe HaskellSafe-Inferred
LanguageHaskell2010

Toml.Codec.Combinator.List

Description

TOML-specific combinators for converting between TOML and Haskell list-like data types.

There are two way to represent list-like structures with the tomland library.

  • Ordinary array lists of primitives:

    foo = [100, 200, 300]

  • Lists via tables:

    foo =
    [ {x = 100}
    , {x = 200}
    , {x = 300}
    ]

OR

[[foo]]
    x = 100
[[foo]]
    x = 200
[[foo]]
    x = 300

You can find both types of the codecs in this module for different list-like structures. See the following table for the better understanding:

Haskell TypeTOMLTomlCodec
[Int]a = [1, 2, 3]arrayOf _Int "a"
NonEmpty Inta = [11, 42]arrayNonEmptyOf _Int "a"
[Text]x = [{a = "foo"}, {a = "bar"}]list (text "a") "x"
NonEmpty Textx = [{a = "foo"}, {a = "bar"}]nonEmpty (text "a") "x"

Since: 1.3.0.0

Synopsis

Array lists

arrayOf :: TomlBiMap a AnyValue -> Key -> TomlCodec [a] Source #

Codec for list of values. Takes converter for single value and returns a list of values.

Example:

Haskell [Int] can look like this in your TOML file:

foo = [1, 2, 3]

If the key is not present in TOML the following decode error will be spotted:

tomland decode error:  Key foo is not found

Since: 0.1.0

arrayNonEmptyOf :: TomlBiMap a AnyValue -> Key -> TomlCodec (NonEmpty a) Source #

Codec for non- empty lists of values. Takes converter for single value and returns a non-empty list of values.

Example:

Haskell NonEmpty Int can look like this in your TOML file:

foo = [1, 2, 3]

If you try to decode an empty TOML list you will see the error:

tomland decode error:  Empty array list, but expected NonEmpty

If the key is not present in TOML the following decode error will be spotted:

tomland decode error:  Key foo is not found

Since: 0.5.0

Table lists

list :: forall a. TomlCodec a -> Key -> TomlCodec [a] Source #

Codec for list of values. Represented in TOML as array of tables.

Example:

Haskell [Int] can look like this in your TOML file:

foo =
  [ {a = 1}
  , {a = 2}
  , {a = 3}
  ]

Decodes to an empty list [] when the key is not present.

Since: 1.0.0

nonEmpty :: forall a. TomlCodec a -> Key -> TomlCodec (NonEmpty a) Source #

Codec for NonEmpty list of values. Represented in TOML as array of tables.

Example:

Haskell NonEmpty Int can look like this in your TOML file:

foo =
  [ {a = 1}
  , {a = 2}
  , {a = 3}
  ]

If you try to decode an empty TOML list you will see the error:

tomland decode error:  Table array [[foo]] is not found

or

tomland decode error:  Key foo.a is not found

If the key is not present in TOML the following decode error will be spotted:

tomland decode error:  Table array [[foo]] is not found

Since: 1.0.0