Abstract. We describe DMSL, a domain specific language for defining schema mappings. Schema mappings are assertions in carefully crafted logics that express constraints between data represented in different formats, including XML and relational schema. DMSL is suitable for representing programs over mappings, which, for instance, occur in dataflow graphs of mappings. DMSL programs of mapping type are statically guaranteed by a qualified type system to denote satisfiable constraints; the principal polymorphic schemas of source and target solution data instances are automatically inferred. DMSL implements a variety of operations over mappings (e.g., composition) by interfacing with IBM’s Clio Mapping Engine. 1

Aspect-Oriented Programming (AOP) aims at modularising crosscutting concerns that show up in software. The success of AOP has been almost viral and nearly all areas in Software Engineering and Programming Languages have become “infected ” by the AOP bug in one way or another. Interestingly the functional programming community (and, in particular, the pure functional programming community) seems to be resistant to the pandemic. The goal of this paper is to debate the possible causes of the functional programming community’s resistance and to raise awareness and interest by showcasing the benefits that could be gained from having a functional AOP language. At the same time, we identify the main challenges and explore the possible design-space. Categories and Subject Descriptors D.3.2 [Programming Languages]: Language Classifications—Applicative (functional) languages,