December 27, 2025
Tiny Ruby, giant opinions
Mruby: Ruby for Embedded Systems
Tiny Ruby hits gadgets; devs yell 'Lua-ish,' hype Dreamcast, and nickname it Murby
TLDR: Mruby is a lightweight Ruby you can bundle into apps, with tools to compile Ruby code, and even a micro cousin for microcontrollers. Comments erupted over whether it’s for gadgets or for embedding like Lua, with jokes ("Murby"), retro Dreamcast hype, and a cross-platform twist via Cosmopolitan libc.
Ruby just hit fun-size. Mruby is a slimmed-down Ruby you can tuck inside apps or gadgets, with a tiny interpreter, a REPL (an interactive shell), and a compiler that can even spit out C code. Version 3.4 is live, docs build with one command, and it’s MIT-licensed.
But the comments? Spicy. One camp insists mruby isn’t really “for embedded devices” so much as it’s a script engine you embed—more “Lua vibes” than soldering iron. Another crowd fires back with mruby/c, an even smaller cousin for single‑chip boards. The language-love vs implementation-trust debate hits hard: Ruby-ish feel versus Lua’s battle-tested engine.
Chaos level: delightful. Someone rebrands it “Murby.” Retro gamers drop a gem: a talk on making Sega Dreamcast games with mruby by Yuji Yokoo—watch it here. And a sharp-eyed commenter flags a Cosmopolitan libc pull request, fueling dreams of one binary that runs almost anywhere. There’s no mailing list—questions and gripes go straight to GitHub issues, which only stoked the live‑fire feedback loop.
Verdict: the code is light, the opinions are heavy. Whether you’re Team Lua-ish, Team Microcontroller, or Team Dreamcast Nostalgia, mruby’s tiny footprint just kicked off a giant comment-section brawl.
Key Points
- •mruby is a lightweight Ruby implementation compatible with Ruby 3.x syntax (excluding pattern matching) and designed for embedding in applications.
- •Included tools are the mruby interpreter, the mirb interactive shell, and the mrbc compiler, which can output bytecode or C source.
- •Stable version 3.4.0 is available on GitHub; users can also clone the trunk or use ruby-install, ruby-build, or rvm to install and compile.
- •Build and documentation processes use rake; API docs are generated by YARD and C API docs by Doxygen and Graphviz.
- •mruby is MIT-licensed with guidance on copyright display (“mruby developers”), and contributions are accepted via GitHub pull requests under non-exclusive rights.