International audienceIt is our great pleasure to host the fourth edition of the Domain-Specific Aspect Languages workshop (DSAL09), as part of the eight International Conference on Aspect-Oriented Software Development (AOSD09). The tendency to raise the abstraction level in programming languages towards a particular domain is also a major driving force in the research domain of aspect-oriented programming languages. The DSAL workshop series aims to bring the research communities of domain-specific language engineering and domain-specific aspect design together. In the editions held at GPCE06/OOPSLA06 and AOSD07 we approached domain-specific aspect languages both from a design and a language implementation point of view. At AOSD08 we explic...