/Sprache

Tiny C# Monadic Parser Framework

Primary LanguageC#MIT LicenseMIT

Sprache is a simple, lightweight library for constructing parsers directly in C# code.

It doesn't compete with "industrial strength" language workbenches - it fits somewhere in between regular expressions and a full-featured toolset like ANTLR.

Usage

Join the chat at https://gitter.im/sprache/Sprache

Unlike most parser-building frameworks, you use Sprache directly from your program code, and don't need to set up any build-time code generation tasks. Sprache itself is a single tiny assembly.

A simple parser might parse a sequence of characters:

// Parse any number of capital 'A's in a row
var parseA = Parse.Char('A').AtLeastOnce();

Sprache provides a number of built-in functions that can make bigger parsers from smaller ones, often callable via Linq query comprehensions:

Parser<string> identifier =
    from leading in Parse.WhiteSpace.Many()
    from first in Parse.Letter.Once()
    from rest in Parse.LetterOrDigit.Many()
    from trailing in Parse.WhiteSpace.Many()
    select new string(first.Concat(rest).ToArray());

var id = identifier.Parse(" abc123  ");

Assert.AreEqual("abc123", id);

Examples and Tutorials

The best place to start is this introductory article.

Examples included with the source demonstrate:

Tutorials explaining Sprache:

Real-world parsers built with Sprache:

Background

Parser combinators are covered extensively on the web. The original paper describing the monadic implementation by Graham Hutton and Eric Meijer is very readable. Sprache was originally written by Nicholas Blumhardt and grew out of some exercises in Hutton's Haskell book.

The implementation of Sprache draws on ideas from: