Originally published on strict-lang.org. By Benjamin Nitschke.
Last year's July 2025 post ended with the plan to get the runtime working, "switch all the code to Strict itself and let it rip". This month that happened: Strict compiles itself. The compiler is no longer C#. It is a set of .strict packages that build into one native executable, strict, which then builds its own sources again, byte for byte identical.
What is finished
- No more .NET. Master is Strict only. The C# implementation that bootstrapped everything moved to the
dotnet branch. A fresh checkout starts from Compiler/Bootstrap.mlir, the compiler as MLIR, and needs nothing but the LLVM tools.
- Everything is written in Strict: the tokenizer, parser and type inference (
Expressions), the rules (Validators), bytecode generation and linking (Bytecode), the Strict VM (Runtime) and the MLIR code generation (Compiler). See Architecture for what each type does.
- One command line tool:
strict file.strict runs a file like python file.py, plus strict build | test | check | version. Put the Strict folder on your PATH and it works in any folder, see Getting Started.
- Native executables for Windows and Linux through MLIR,
mlir-opt, mlir-translate and clang, with a mark-sweep garbage collector. 1 million loop iterations take 45 ms natively, 245 ms on the Strict VM and 420 ms with the old C# Strict.exe. strict builds itself in about 10 seconds.
- All 41 example programs run on the natively compiled Strict VM like they did with C#, and 296 files pass all their inline tests natively.
- Stricter rules: parameters can't be
mutable anymore (return the changed value instead), keywords can't be names, and is Error works for any value in native code.
- VS Code is the main editor now. The extension runs everything through
strict, no language server process needed: SCrunch tests every file when a folder opens and on every save, shows green and red test dots, validator diagnostics and quick fixes, and runs programs with Ctrl+Shift+R.
- This website has a new language guide, a cheat sheet and a page for every base type.
What is next
The improvements list is in priority order: generic types like Dictionary in native code, operators between lists, the same test results on the Strict VM as natively, better test output for VS Code, and removing the older line-based packages. After that comes a language server written in Strict, for autocomplete and go to definition in VS Code.