Metamorphic Domain-Specific Languages: A Journey Into the Shapes of a Language

TL;DR

This paper explores metamorphic domain-specific languages (DSLs) that can adapt their shape to user needs, demonstrating a four-year journey in developing and maintaining such flexible languages in feature modeling.

Contribution

It introduces the concept of metamorphic DSLs that can change form, showing practical development of external and internal DSLs with adaptable shapes.

Findings

No single best solution; multiple language shapes are valuable.

Maintaining both external and internal DSLs is beneficial.

Metamorphic DSLs can adapt to different tasks and environments.

Abstract

External or internal domain-specific languages (DSLs) or (fluent) APIs? Whoever you are -- a developer or a user of a DSL -- you usually have to choose your side; you should not! What about metamorphic DSLs that change their shape according to your needs? We report on our 4-years journey of providing the "right" support (in the domain of feature modeling), leading us to develop an external DSL, different shapes of an internal API, and maintain all these languages. A key insight is that there is no one-size-fits-all solution or no clear superiority of a solution compared to another. On the contrary, we found that it does make sense to continue the maintenance of an external and internal DSL. The vision that we foresee for the future of software languages is their ability to be self-adaptable to the most appropriate shape (including the corresponding integrated development environment) according to a particular usage or task. We call metamorphic DSL such a language, able to change from one shape to another shape.