Compact language implementations are increasingly popular for use in resource constrained environments. For embedded applications such as robotics and home automation, it is useful to support a Read-Eval-Print-Loop (REPL) so that a basic level of interactive development is possible directly on the device. Due to its minimalistic design the Scheme language is particularly well suited for such applications and several implementations are available with different tradeoffs. In this paper we explain the design and implementation of a compact Scheme system that supports a REPL, is extensible and has a 4 KB executable code footprint.

https://github.com/udem-dlteam/ribbit

https://arxiv.org/abs/2310.13589

Abstract.

The Ribbit system is a compact Scheme implementation running on the Ribbit Virtual Machine (RVM) that has been ported to a dozen host languages. It supports a simple Foreign Function Interface (FFI) allowing extensions to the RVM directly from the program’s source code. We have extended the system to offer conformance to the R4RS standard while staying as compact as possible. This leads to a R4RS compliant REPL that fits in an 7 KB Linux executable. This paper explains the various issues encountered and our solutions to make, arguably, the smallest R4RS conformant Scheme implementation of all time.

Previous:

https://news.ycombinator.com/item?id=31096771

https://news.ycombinator.com/item?id=41524517

Try the online R4RS REPL here :

https://udem-dlteam.github.io/ribbit/repl-r4rs-tc.html