Domain Specific Languages (DSLs) are limited forms of computer language designed for a specific class of problems. In this
JAOO conference talk, Martin Fowler introduces a simple example of DSL, bringing out the difference between external and internal DSLs, and talking through the trade-offs in using both forms.
Watch:
Introduction to Domain Specific Languages (25 mins)
The content of this presentation is based on the first part of Martin Fowler's
Language Workbench essay. You can also find all InfoQ content about DSLs at:
http://infoq.com/dsl, including
this article about recent ideas and debates.