feature Bernard Lambeau, a Belgium-based software developer and founder of several technology companies, created a programming language called Elo with the help of Anthropic’s Claude Code.
Starting on December 25, 2025, he published a series of posts about the project. The first post names Claude as a co-author.
"In roughly 24 hours of collaboration, we built a complete expression language with a parser, type system, three compilers, a standard library, a CLI tool, and a documentation website. Not bad for a day’s work,” Lambeau and Claude wrote.
"Elo isn’t just a demonstration that AI can write code. It’s a demonstration that humans and AI can build together – each contributing what they do best,” they added.
As an expression language that compiles to JavaScript, Ruby, and SQL, Elo is intended as a portable way to handle form validation, e-commerce order processing, and subscription logic.
Lambeau, founder and CTO of Klaro Cards and CEO of app consultancy Enspirit, is not the first to develop a programming language with the help of AI.
Steve Klabnik performed a similar feat last year with the Rue programming language. In September 2025, Geoffrey Huntley enlisted Claude to write a programming language called Cursed. And before that, Avital Tamir published a Claude-authored repo for the Server programming language, with the caveat that the code is not intended for actual use.
Claude Code isn’t the only AI-assisted programming method having a moment. AI biz Cursor created a rudimentary browser using OpenAI’s GPT-5.2. And developer Ola Prøis used Cursor, powered by Claude, to create a Rust-based text editor called Ferrite.
Claude users generally acknowledge that their pair partner makes mistakes. But those committed to AI assistance find it worthwhile to clean up after their helper.
"Claude Code knows almost every tech stack (and can search the web), knows the Linux commands that matter (search code, search & replace, compile, test, etc.), and does that 10x faster than I can do myself," Lambeau told The Register in an email interview.
Claude, he said, allows him to use technology he hasn’t mastered.
"I was already a full-stack developer (on languages, frameworks & reusable libraries I knew); I’m now a full-stack++ dev because I can also use languages, frameworks, and reusable libraries I barely know, if at all," he explained.