Kadlet

A .NET implementation of a parser for the KDL Document Language. Most of its logic and structure is based around kdl4j by hkolbeck.

Install

The package is available at NuGet.

Usage

using System.IO;
using Kadlet;

// ...
KdlReader reader = new KdlReader(KdlPrintOptions.PrettyPrint);

using (FileStream fs = File.OpenRead("file.kdl")) {
    KdlDocument document = reader.Parse(fs);
    using (StringWriter sw = new StringWriter()) {
        document.Write(sw);
        Console.Write(sw.ToString());
    };
}

The resulting KdlDocument can be traversed or written back into a stream or string with its methods Write or ToKdlString. The output format can be customized by changing the fields of a KdlPrintOptions instance and passing it as an argument.

The values in properties and arguments are encapsulated in a wrapper KdlValue<T> object, of which there are derivations for most commonly used types. Integers are returned as a KdlInt32 (int), a KdlInt64 (long), or a KdlBigInteger depending on their size. Floating point numbers are returned as a KdlFloat64 by default.

Type annotations

Kadlet supports type annotation overrides, instructing the parser to interpret annotated values differently according to their type.

KdlDocument overrides = reader.Parse(@"
    node (u8)123
    node (f32)123
");

Console.Write(overrides.ToKdlString());

// Output:
//
// node (u8)123
// node (f32)123.0

All numeric overrides are supported save for isize and usize, which are ignored. The following string overrides are supported.

• date-time
• date
• time
• decimal
• ipv4
• ìpv6
• regex
• base64

Custom type annotations

It's possible to define string overrides for custom types.

public enum Color { Red = 1, Green = 2, Blue = 3 };
        
// ...

Dictionary<string, KdlTypeConverter> converters = new Dictionary<string, KdlTypeConverter> {
    {"hex", (input, type) => new KdlByteArray(Convert.FromHexString(input), type)},
    {"color", (input, type) => new KdlEnum(Enum.Parse<Color>(input, true), type)} // slow due to Enum.Parse
};

KdlReader reader = new KdlReader(new KdlReaderOptions {
    TypeConverters = converters
});

string kdl = "node (hex)\"5F3759DF\" (color)\"green\"";

KdlDocument doc = reader.Parse(kdl);
Console.Write(doc.ToKdlString());

// Output:
// node (hex)"XzdZ3w== (color)"Green"

Remarks

This library is in an early state and bugs may be found. Issues and pull requests are welcome and encouraged.

License

Kadlet is made available under the MIT license.