EasyChess: A Domain-Specific Language for Chess Notation

EasyChess is a domain-specific modeling language (DSML) for chess notation, built with Xtext and Xtend inside the Eclipse IDE ecosystem.

What is a DSML?

A domain-specific modeling language lets domain experts express ideas in their own vocabulary rather than a general-purpose programming language. For chess, that means writing game notation in a form that can be validated, highlighted, and transformed automatically.

The Language

EasyChess allows you to write annotated chess games like:

game KasparovVsDeepBlue1997 {
  white: "Kasparov"
  black: "Deep Blue"
  
  1. e4 e5
  2. Nf3 Nc6
  3. Bb5 a6
}

The toolchain validates move legality, highlights syntax, and can generate PGN output.

Technical Stack

• Xtext for grammar definition and parser generation

• Xtend for code generation (PGN export)

• JUnit for grammar validation tests

• Eclipse IDE as the host platform

Lessons Learned

Xtext's grammar DSL is powerful but has a steep learning curve. The most interesting challenge was implementing move validation — chess rules are deceptively complex once you account for en passant, castling rights, and check detection.

Source: GitHub