planckforth: Bootstrapping a Forth interpreter from hand-written tiny ELF binary

Published: 3 days ago (February 16, 2026 at 06:44 AM EST)

2 min read

Source: Hacker News

PlanckForth: Bootstrapping an Interpreter from Handwritten 1KB Binary

Only xxd is needed to build PlanckForth.

git clone https://github.com/nineties/planckforth.git
cd planckforth
make
# The makefile runs:
# xxd -r -c 8 planck.xxd > planck
chmod +x planck

Implementations in other languages are in the others directory.

Running the tiny binary directly:

./planck
kHtketkltkltkotk tkWtkotkrtkltkdtk!tk:k0-tk0k0-Q

After bootstrapping with bootstrap.fs:

./planck  b)

Word	Meaning	Stack effect	Description
=	equal	( a b — c )	`c = (a == b)`
(	shl	( a b — c )	`c = a > b` (logical)
%	sar	( a b — c )	`c = a >> b` (arithmetic)
v	argv	( — a‑addr u )	Argument vector and count
V	version	( — c‑addr )	Runtime information string

binary layout

Implementation	Build command	Test status
Handwritten ELF binary for i386‑linux	`make`
C	`make c`
Python 3.x	`make python`