Domain-specific languages (DSLs) can greatly ease program development compared to general-purpose languages, but the cost of implementing a domain-specific language can be prohibitively high compared to the perceived benefit. This is more pronounced for narrower domains, and perhaps most acute for domain-specific aspect languages (DSALs).

A common technique for implementing a DSL is writing a software library in an existing programming language. Although this does not have the same syntactic appeal and possibilities as a full implementation, it is a technique familiar to most programmers, and it can be done cheaply compared to developing a full DSL compiler. Subsequently, the desired notation may be implemented as a simple syntactic preprocessor. The cross-cutting nature of DSALs, however, makes it difficult to encapsulate these in libraries.

In this paper, we show a technique for implementing a DSAL as a library+notation. We realize this by implementing the library in a program transformation system and the notation as a syntactic extension of the subject language. We discuss our experience with applying this technique to multiple kinds of DSALs.