Cromo: a compiled language with a compiler, library and GUI toolkit
A developer designed Cromo, a C-like language compiled through LLVM, and had Claude Code write most of the compiler, standard library, GUI toolkit and a 300-page guide.
Credits
- Reddit poster ApprehensiveAerie655 Source ↗
Earliest dated source:
The full story
Cromo is a general-purpose programming language with C and C++ syntax that compiles to native code through LLVM. It has no pointers, no garbage collector and no null: every value has one owner, and the compiler checks ownership with rules simpler than Rust's because references only exist as function parameters.
Its author made every design decision; Claude Code wrote most of the compiler, the standard library (HTTP, TLS, JSON, threads and a GUI toolkit whose apps also build for Android) and a 300-page guide.
The process is strict: each choice is discussed, decided by the author and written to a dated decision log before any code, and Claude may propose options but not pick one. The log held 527 decisions at the time of posting.
How it was done
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Sources
From a short post by the maker, so the details are as they tell them.
- Reddit: I built a programming language with Claude Code: compiler, standard library, GUI toolkit and a 300-pReddit poster: ApprehensiveAerie655Posted
The author's post in r/BuildWithClaude describing the language and the way it was built.