Pattern By Example

Program-Transformation.Org: The Program Transformation Wiki
Pattern By Example (PBE) provides a mechanism to implement code patterns for any target language - instead of applying the same theoretical concepts again and again. These code patterns are defined and applied in an interactive way. Any given fragment of code may be enhanced by the definition of variable slots and optional code blocks. The result is a re-usable implementation of the original solution.

PBE Homepage: