Metamodel-based Language Definition with Python

Most of the parser tools are concentrated on concrete syntax and grammar definition. This paper describes a language definition tool that uses a metamodel specification instead of grammar as the basis of the language definition. Inspired by a similar Java tool known as YAJCo, the metamodel is defined using usual object-oriented techniques—as classes in the Python programming language, and the result of the parsing process is a graph of objects. The tool is demonstrated in a case study of a simple imperative programming language. We explain our design decisions and also demonstrate the suitability of a dynamic language such, as Python, for this task.