Dependent Type Systems as Macros.
Stephen Chang, Michael Ballantyne, Milo Turner, William J. Bowman.
47th ACM SIGPLAN Symposium on Principles of Programming Languages (POPL 2020), New Orleans, LA, USA, January 2020 (to appear).

[ pdf  | ACM link  | Turnstile+ code repo  | Cur code repo  | artifact  | slides  ]

We present Turnstile+, a high-level, macros-based metaDSL for building dependently typed languages.

With it, programmers may rapidly prototype and iterate on the design of new dependently typed features and extensions.

Or they may create entirely new DSLs whose dependent type ``power'' is tailored to a specific domain.

Our framework's support of language-oriented programming also makes it suitable for experimenting with systems of interacting components, e.g., a proof assistant and its companion DSLs.

This paper explains the implementation details of Turnstile+, as well as how it may be used to create a wide-variety of dependently typed languages, from a lightweight one with indexed types, to a full spectrum proof assistant, complete with a tactic system and extensions for features like sized types and SMT interaction.