Towards a Language for Defining Reusable Programming Language Components

Developing programming languages is a difficult task that requires a lot of time, effort, and expertise. Reusable programming language components make this task easier, by allowing language designers to grab off-the-shelf components for common language features. Modern functional programming languages, however, lack support for reuse of definitions, and thus language components defined using algebraic data types and pattern matching functions cannot be reused without modifying or copying existing code. To improve the situation, we introduce CS, a functional meta-language for developing reusable programming language components, that features built-in support for extensible data types and functions, as well as effects and handlers. In CS, we can define language components using algebraic data types and pattern matching functions, such that we can compose language components into larger languages and define new interpretations for existing components without modifying existing definitions.