A Surprisingly Simple Lua Compiler

Dynamically-typed programming languages are often implemented using interpreters, which offer several advantages in terms of portability and flexibility of the implementation. However, as a language matures and its programs get bigger, programmers may seek compilers, to avoid the interpretation overhead. In this study, we present LuaAOT, a simple ahead-of-time compiler for Lua. The compiler is derived from the Lua interpreter and it exemplifies an old idea of using partial evaluation to produce a compiler based on an existing interpreter. Our contribution is to apply this idea to a well-established programming language. We show that with a quite modest effort it is possible to implement an efficient compiler that covers the entirety of Lua, including coroutines and tail calls. The whole implementation required less than 500 lines of new code. For this effort, we reduced the running time of our benchmarks from 20% to 60%.