Simon Willison’s Weblog

jordanhubbard/nanolang (via) Plenty of people have mused about what a new programming language specifically designed to be used by LLMs might look like. Jordan Hubbard (co-founder of FreeBSD, with serious stints at Apple and NVIDIA) just released exactly that.

A minimal, LLM-friendly programming language with mandatory testing and unambiguous syntax.

NanoLang transpiles to C for native performance while providing a clean, modern syntax optimized for both human readability and AI code generation.

The syntax strikes me as an interesting mix between C, Lisp and Rust.

I decided to see if an LLM could produce working code in it directly, given the necessary context. I started with this MEMORY.md file, which begins:

Purpose: This file is designed specifically for Large Language Model consumption. It contains the essential knowledge needed to generate, debug, and understand NanoLang code. Pair this with spec.json for complete language coverage.

I ran that using LLM and llm-anthropic like this:

llm -m claude-opus-4.5 \
  -s https://raw.githubusercontent.com/jordanhubbard/nanolang/refs/heads/main/MEMORY.md \
  'Build me a mandelbrot fractal CLI tool in this language' 
  > /tmp/fractal.nano

The resulting code... did not compile.

I may have been too optimistic expecting a one-shot working program for a new language like this. So I ran a clone of the actual project, copied in my program and had Claude Code take a look at the failing compiler output.

... and it worked! Claude happily grepped its way through the various examples/ and built me a working program.

Here's the Claude Code transcript - you can see it reading relevant examples here - and here's the finished code plus its output.

I've suspected for a while that LLMs and coding agents might significantly reduce the friction involved in launching a new language. This result reinforces my opinion.