TOML parser for C3

A TOML v1.0.0 parser and validator for the C3 programming language.

• Implements the full TOML v1.0.0 specification.
• Decodes TOML data into structs (example below).
• Fully passes the official toml-test suite.
• Includes a command-line TOML validator tool tomlv for syntax checking.

Usage

TOML configuration files can be parsed from a String, an InStream (e.g. File), or directly from a file path.

Read data from String s:

TomlData config = toml::from_string(s)!;

Read data from InStream in:

TomlData config = toml::from_stream(in)!;

Read data directly from a file path:

TomlData config = toml::from_file("test.toml")!;

The toml::from_* functions accept two additional arguments: a memory allocator and a flag for error verbosity. The default allocator is mem.

To access a configuration value, use TomlData.get (or the [] operator) with dotted-key notation.

For example, given:

[fruit]
color = 0x3AA832

you can read the hex value with: config.get("fruit.color"); or: config["fruit.color"];

Both return a pointer of type std::collections::Object*.

Error handling

When parsing errors occur, detailed diagnostics are printed to stderr, including the line, column and error type:

$ echo "\"a quoted key without a value\"" | build/tomlv
TOML ERROR -- Line 1, Col 31: expected '='
TOML ERROR -- Line 1, Col 31: parser::MISSING_KEYVAL_SEPARATOR
"a quoted key without a value"
                              ^
  Invalid TOML: parser::MISSING_KEYVAL_SEPARATOR

Error messages can be silenced by setting the optional verbose to false in any of the toml::from_* functions.

Decoding into Structs

Parsed TOML data can be directly decoded into a user-defined struct MyStructusing toml::decode{MyStruct}:

TomlData toml = toml::from_string(s)!!;
MyConfig my_config = toml::decode{MyConfig}(toml)!!;

Decoding into arrays is currently only implemented for fixed-sized arrays of type Object*.

For a more detailed example, see below.

Installation

Add the library as a submodule to your C3 project:

git submodule add http://github.com/konimarti/toml.c3l lib

Then update your project.json to include:

{
    "dependency-search-paths": [ "lib" ],
    "dependencies": [ "toml" ]
}

Adjust dependency-search-paths if you keep the submodule in a different directory.

Running tests

To verify correctness, use the official TOML test suite:

go install github.com/toml-lang/toml-test/cmd/toml-test@v1.6.0
c3c build tomlv
toml-test -- build/tomlv -j

Examples

Parse TOML from String

module app;

import std::io, toml;

fn void main() => @pool()
{	
    String s = `
    # toml comment
    title = "TOML example"
    [database]
    ports = [8000, 8001, 8002]`;

    TomlData cfg = toml::from_string(s, tmem)!!;

	io::printfn("title: %s", cfg.get("title")!!);
	io::printfn("ports: %s", cfg.get("database.ports")!!);
}
// Output:
// title: "TOML example"
// ports: [8000,8001,8002]

Parse TOML and decode to struct

module tomltest;

import std::io, toml;

struct Fruit
{
	String name;
	int    color;
	double price;
	bool   fresh;
}

struct TomlConfig
{
	String title;
	Fruit  fruit;
}

fn void main()
{
	String s = `
	title = "TOML example"

	[fruit]
	name = "apple"
	color = 0xbeef
	price = 1.32
	fresh = true`;

	TomlData toml = toml::from_string(s)!!;
	defer toml.free();

	TomlConfig my_config = toml::decode{TomlConfig}(toml);

	io::printn(my_config);
}
// Output:
// { title: TOML example, fruit: { name: apple, color: 48879, price: 1.320000, fresh: true } }