Extracting a domain specific language from an example: a bottom-up method using the ngrease metalanguage

ABSTRACT

This demonstration shows a lightweight and fast method for creating a tested and working domain specific language. The method is demonstrated using the ngrease metalanguage.

The creation of a new language is started by writing a representative example of the final product with a test that tests the transformation from a stub source to the result.

The test is made to pass by writing a constant transformer that unconditionally outputs the result.

At each step the language is extended by refactoring: Some part of the transformer template is converted from a constant subtree to a reference to data read from the source tree, thus driving additions to the new language.

Optionally, each refactoring step can be driven by a new test that demonstrates the lack of parameterization of some part of the final product.

REFERENCES

• 1: http://ngrease.sourceforge.net/introduction.html
• 2: http://www.refactoring.com/catalog/parameterizeMethod.html; accessed 25.7.2007

INDEX TERMS

Primary Classification:
  D. Software
  D.2 SOFTWARE ENGINEERING
      D.2.3 Coding Tools and Techniques

General Terms:
Languages

Keywords:
DSL, code generation, metaprogramming, method, refactoring