SFX – A language where 0.1 and 0.2 = 0.3 and Context is first-class
I've spent the last few weeks building SFX in Rust. It's a programming language experiment focused on context-oriented programming with some unusual design choices. Reality check first: Solo project, 53 commits 1 GitHub star xD Zero users besides me No production usage Documentation is aspirational Many stdlib modules are minimal stubs What actually works: Basic interpreter (tree-walker) Arbitrary precision decimals (0.1 + 0.2 = 0.3) 1-based indexing (controversial, I know) Context/Situation system (the main idea) Some file I/O and basic networking JIT hooks exist but optimization…
In plain words
SFX is an experimental programming language built in Rust that prioritizes context-oriented programming as its core feature. It includes a tree-walker interpreter with arbitrary-precision decimal arithmetic that correctly handles operations like 0.1 + 0.2 = 0.3, uses 1-based indexing, and supports basic file I/O and networking. The language's main innovation is its Situation system, which allows methods to be overridden based on context rather than requiring conditional checks throughout code. Currently a solo project with minimal documentation and standard library, SFX is intended for developers interested in experimenting with context-oriented language design.
written from the facts on this page · September 2026
From the sources
In the maker’s words, at launch
I've spent the last few weeks building SFX in Rust. It's a programming language experiment focused on context-oriented programming with some unusual design choices. Reality check first: Solo project, 53 commits 1 GitHub star xD Zero users besides me No production usage Documentation is aspirational Many stdlib modules are minimal stubs What actually works: Basic interpreter (tree-walker) Arbitrary precision decimals (0.1 + 0.2 = 0.3) 1-based indexing (controversial, I know) Context/Situation system (the main idea) Some file I/O and basic networking JIT hooks exist but optimization is minimal The Context idea (asking for feedback on this): Instead of checking if (user.isAdmin) everywhere, you define Situation: AdminMode that overrides methods: Concept: User To GetPermissions: Return "read" Situation: AdminMode Adjust User: To GetPermissions: Return "admin,write,delete" Story: Create User Called Bob Switch on AdminMode Print Bob.GetPermissions # Now returns "admin,write,delete" Objects change behavior based on active situations without mutating state. Is this useful or just overengineered? What's NOT ready: Performance is terrible (haven't optimized anything) Standard lib is mostly TODOs AI features are vaporware REPL doesn't exist No tooling (LSP, debugger, etc.) Tests exist but coverage is poor My questions: Is context-oriented programming solving a real problem or creating busywork? Should I focus on making it fast OR making the stdlib useful? Is 1-based indexing a dealbreaker for you? Would arbitrary precision by default bother you for a general-purpose language? I'm not trying to replace anything. This is a learning project that got out of hand. Repo: https://github.com/roriau0422/sfex-lang Pages: https://roriau0422.github.io/sfex-lang/ Honest feedback wanted - including "this is pointless, stop wasting time."
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