package toml-cconv

Toml (OCaml parser for TOML)

OCaml parser for TOML (Tom's Obvious Minimal Language) v0.4.0.

Table of contents

• A foreword to beginners
• Dependencies
• Install
• Documentation
• Usage
• Reading Toml data
• Writing Toml data
• Limitations

A foreword to beginners

New to OCaml ? Don't worry, just check theses links to begin with:

• Play with OCaml online and discover the language
• See OCaml code examples
• The full official list of Ocaml tutorials

• Recommended tools:

  • OCaml Package Manager (also install compilers)
  • OCaml IDE
  • OCaml Interpretor

Dependencies

Toml need OCaml 4.0 at least. Check your local installation with ocamlc -v.

This project use ocamllex and menhir parsing features. In order to compile tests you will also need OUnit and bisect is required to generate code coverage summary.

Install

• Via OPAM: opam install toml
• From source:

git clone https://github.com/sagotch/To.ml
cd To.ml
make install-dependencies # install To.ml dev dependencies
make all 		  # build and test
make install              # do the local installation

make install may need sudo.

Toml-cconv

A second library for encoding/decoding with cconv can be installed if cconv is present:

• Via OPAM: opam install toml-cconv
• From source:

make install-dependencies
make all-cconv
make install-cconv

Documentation

You can build documentation from sources with make doc, if odoc is installed, or browse github pages of the project.

Usage

open Toml in your file(s), and link the toml library when compiling. For instance, using ocamlbuild:

ocamlbuild -use-ocamlfind -package toml foo.byte

or using an OCaml toplevel (like utop):

$ utop
utop # #use "topfind";;
utop # #require "toml";; (* now you can use the Toml module *)

Reading Toml data

utop # (* 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> 

utop # (* 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 : TomlTypes.table = <abstr>

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

Writing Toml data

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

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

Lenses

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

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

utop # TomlLenses.(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

utop # let maybe_toml_data' = TomlLenses.(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' : TomlTypes.table option = Some <abstr>

utop # Toml.Printer.string_of_table toml_data';;
- : bytes = "[this.is.a.deeply.nested.table]\nanswer = 2015\n"

PPX support

To.ml supports ppx via cconv

utop # #require "cconv.ppx";;
utop # #require "toml.cconv";;

utop # type t = { ints : int list; string : string } [@@deriving cconv];;
type t = { ints : int list; string : string; }                                                  
val encode : t CConv.Encode.encoder = {CConv.Encode.emit = <fun>}                               
val decode : t CConv.Decode.decoder =
  {CConv.Decode.dec =
    {CConv.Decode.accept_unit = <fun>; accept_bool = <fun>;
     accept_float = <fun>; accept_int = <fun>; accept_int32 = <fun>;
     accept_int64 = <fun>; accept_nativeint = <fun>; accept_char = <fun>;
     accept_string = <fun>; accept_list = <fun>; accept_option = <fun>;
     accept_record = <fun>; accept_tuple = <fun>; accept_sum = <fun>}}

utop # let toml = Toml.Parser.(from_string "ints = [1, 2]\nstring = \"string value\"\n"
                               |> unsafe);;
val toml : TomlTypes.table = <abstr>

utop # TomlCconv.decode_exn decode toml;;
- : t = {ints = [1; 2]; string = "string value"}

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 '#'.

Contributing

• Fork this repository
• You will need opam and dune
• Fetch the dependencies with make install-dependencies
• Test with make test
• Submit a PR or open an issue so that we can create a branch and a PR associated to it. This is better because then, all the Toml maintainers can push commits to this branch.