Build Your Own Forth Interpreter

Retro die-hards vs weekend builders: the comments are wild

TLDR: A challenge invites coders to build a tiny Forth interpreter, learn stacks, and do simple programs. Comments erupt into purists demanding bare-metal builds versus practical folks celebrating accessibility, with retro flexes, tutorial links, and an NES dev hoping Forth beats assembly—proving old-tech still sparks big feelings.

Feeling brave? A new coding challenge dares you to build a Forth-like interpreter—think a tiny language that uses a stack and “Reverse Polish Notation” (numbers first, math after). It’s friendly: pick web, desktop, or command line; type “bye” to exit; chase Fibonacci and FizzBuzz. But the comments? Pure fireworks.

The vibe split fast. One purist tossed a koan into the crowd: “if you know one forth, you know one forth”—translation: every Forth is its own weird little beast, and that’s the charm. Another voice expected bare-metal wizardry: “I was expecting to see FORTH in bare metal C or ASM,” scoffing at anything less than soldered-to-the-metal authenticity. Meanwhile, the myth that Forth is “write-only” got roasted as gatekeeping, with folks insisting it’s easy once you get the stack mindset.

Then the flexes dropped. Retro cred arrived with a “been there, shipped that”: “I’ve already done that—ANS Forth for the 6809” complete with a GitHub link. Deep divers shared a GDB walk-through of JONESFORTH via video. And the wholesome twist: one NES homebrewer admitted assembly is no fun and hopes Forth saves his game dev sanity.

Memes flew about the “ok>” prompt as a retro therapist and “bye” as the rage-quit word. Bottom line: it’s old-school minimalism vs DIY weekend joy, and everyone brought receipts

Key Points

  • The article challenges readers to build a Forth-like interpreter that can run programs like Fibonacci and FizzBuzz.
  • Forth was created by Charles H. “Chuck” Moore, first used by other programmers in 1970, and standardized in 1994.
  • The name FORTH arose due to the IBM 1130’s five-character identifier limit, shortening intended FOURTH.
  • Step Zero covers choosing implementation approach (web, desktop/mobile GUI, CLI), language selection, and learning resources.
  • Step 1 and 2 guide building a REPL with “bye” to exit and adding integer handling plus basic arithmetic (+, -, *, /, mod) on a data stack.

Hottest takes

"if you know one forth, you know one forth" — ithkuil
"I was expecting to see FORTH in bare metal C or ASM" — iberator
"I find assembly considerably un-fun so I wanted to use a higher-level language" — tombert
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