Minimalist Forth: Pushing the Boundaries of Language Size

This article explores how small the core of the Forth language can be. It showcases several minimalist Forth implementations, including PlanckForth (under 1000 bytes), SmithForth (around 1000 bytes), sectorforth (512 bytes), and milliForth (336 bytes). These implementations achieve basic Forth functionality, even including compilers, with extremely small instruction sets. Frank Sergeant's 3-instruction Forth takes this to the extreme, running on a Motorola MC68HC11 chip in a mere 66 bytes. These examples challenge our assumptions about the size of programming languages and demonstrate the elegance of language design.