Luke Imhoff

Using Java, Kotlin, and GrammarKit to reimplement to Erlang, Yecc grammars, and Elixir for static analysis for Elixir source and BEAM bytecode. How decompiling and disassembly tools can quickly answer optimization arguments.

IntelliJ Elixir is the Elixir plugin for JetBrains IDEs like IntelliJ and Rubymine. It uses JetBrains OpenAP, JFlexI and GrammarKit to reimplement the Elixir grammar, which is natively implemented as bespoke Erlang lexer and YECC LALR parser. This meant translating a recursive Erlang lexer into a strict regular expression state machine used by JFlex with some interesting needed extension. Porting the grammar from LALR Yecc to the LL Pratt Parser generated by Grammar Kit involved understanding the non-universality of BNF. Reimplementing and extensive testing of the plugin led to finding bugs in native Elixir, showing that alternative implementations of languages in editors and tools can find bugs in the original implementations. The BEAM bytecode decompiler and disassembler has led to better understanding of how the VM optimizes different Elixir code.

Lumen is an alternative compiler, interpreter and runtime to the BEAM designed for WebAssembly. Lumen allows Erlang and Elixir to run in the browser.

The Lumen project is a reimplementation of the BEAM in Rust. Using Rust, Lumen is able to leverage the cutting edge tools of the Rust WASM ecosystem. Compiling Elixir and Erlang from source to LLVM IR, the Lumen compiler is able to do whole program optimizations allowing for dead-code elimination of parts of the user application, OTP, and the runtime itself. Eliminating the dead code makes shipping OTP size-competitive with JavaScript frameworks, while retaining the benefits of thousands of concurrent processes and supervision trees.