Moduletomland-1.3.3.3Haskell2010

Toml.Codec.Combinator.List

SPDX-License-Identifier : MPL-2.0 Maintainer : Kowainik xrom.xkov@gmail.com Stability : Stable Portability : Portable

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.

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:

Array lists

2 declarations

valuearrayOf :: TomlBiMap a AnyValue -> Key -> TomlCodec [a]

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

valuearrayNonEmptyOf :: TomlBiMap a AnyValue -> Key -> TomlCodec (NonEmpty a)

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

2 declarations

valuelist :: TomlCodec a -> Key -> TomlCodec [a]

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.

valuenonEmpty :: TomlCodec a -> Key -> TomlCodec (NonEmpty a)

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

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