I recently wrote about using first-class functions to help make a BF interpreter. This is a follow-up post to describe a nifty solution to a tricky problem that made my program go 2–5× faster and put it about on-par with an interpreter written in pure C. A basic interpreter works by walking down the AST and evaluating nodes recursively: when the interpreter encounters an expression, it dispatches on the type of expression to decide how to perform the evaluation. Here’s the key insight to...
