toml

OCaml library for TOML.

Documentation

Have a look at the online documentation. Otherwise, here's a quickstart guide.

Reading TOML data

# (* This will return either `Ok $tomltable or `Error $error_with_location *)
  let ok_or_error = Toml.Parser.from_string "key=[1,2]";;
val ok_or_error : Toml.Parser.result = `Ok <abstr>

# (* You can use the 'unsafe' combinator to get the result directly, or an
  exception if a parsing error occurred *)
  let parsed_toml = Toml.Parser.(from_string "key=[1,2]" |> unsafe);;
val parsed_toml : Toml.Types.table = <abstr>

# (* Use simple pattern matching to read the value *)
  Toml.Types.Table.find (Toml.Min.key "key") parsed_toml;;
- : Toml.Types.value = Toml.Types.TArray (Toml.Types.NodeInt [1; 2])

Writing TOML data

# let toml_data = Toml.Min.of_key_values [
    Toml.Min.key "ints", Toml.Types.TArray (Toml.Types.NodeInt [1; 2]);
    Toml.Min.key "string", Toml.Types.TString "string value";
  ];;
val toml_data : Toml.Types.table = <abstr>

# Toml.Printer.string_of_table toml_data;;
- : string = "ints = [1, 2]\nstring = \"string value\"\n"

Lenses

Through lenses, it is possible to read/write deeply nested data with ease. The Toml.Lenses module provides partial lenses (that is, lenses returning option types) to manipulate TOML data structures.

# let toml_data = Toml.Parser.(from_string
    "[this.is.a.deeply.nested.table] answer=42" |> unsafe);;
val toml_data : Toml.Types.table = <abstr>

# Toml.Lenses.(get toml_data (
    key "this" |-- table
    |-- key "is" |-- table
    |-- key "a" |-- table
    |-- key "deeply" |-- table
    |-- key "nested" |-- table
    |-- key "table" |-- table
    |-- key "answer"|-- int ));;
- : int option = Some 42

# let maybe_toml_data' = Toml.Lenses.(set 2015 toml_data (
    key "this" |-- table
    |-- key "is" |-- table
    |-- key "a" |-- table
    |-- key "deeply" |-- table
    |-- key "nested" |-- table
    |-- key "table" |-- table
    |-- key "answer"|-- int ));;
val maybe_toml_data' : Toml.Types.table option = Some <abstr>

# Toml.Printer.string_of_table (Option.get maybe_toml_data');;
- : string = "[this.is.a.deeply.nested.table]\nanswer = 2015\n"

Limitations

• Keys don't quite follow the TOML standard. Both section keys (eg, [key1.key2]) and ordinary keys (key=...) may not contain the following characters: space, \t, \n, \r, ., [, ], " and #.

Projects using toml

• drom
• hll
• pds
• snabela
• soupault

If you want to add your project, feel free to open a PR.