J++
Experimental language where questions and methods are composable values, with a Rust runtime that speaks /v1/systemone and replays runs.
Overview
J++ is an experimental programming language exploring semantic judgment as a programmable operation. Questions are values, methods are values, and composed methods can become building blocks in other methods. Standalone .jpp source runs on a native Rust implementation that parses, checks language rules and executes methods through one shared kernel; an earlier embedded Python 3.12 implementation remains as a behaviour reference. Both speak the /v1/systemone format.
Examples cover three ways in: a batch of items from one sentence of purpose, a process that keeps changing in a small world, and modules you fill in yourself, plus filling missing information and replaying a run from its ledger. All five examples run offline on recorded answers at no cost, and CI installs the binary on clean Ubuntu and macOS machines and checks every documented code block's output. A demos page replays real runs and states what is unsettled. Documentation is in English and Chinese. The roadmap lists reusable source libraries and consistent composition rules as next steps.
What the decision model decides
| Type | Question | Answers |
|---|---|---|
| Other | User-composed questions and methods evaluated by a System One model | — |
How it works
- Write a .jpp program composing questions and methods
- Run it with the jpp command
- Kernel sends questions to a System One endpoint or replays recorded answers
- Results and a ledger are produced for replay
Strengths
- Offline examples via recorded answers
- CI verifies documentation output
- Native binary needs no Python at runtime
Caveats
- Experimental language with unsettled design
- Rust 1.85+ needed to build
- Limited library of methods so far
Getting started
git clone https://github.com/towow-ai/jpp.git && cd jpp/rust && cargo install --locked --path crates/jpp && jpp run examples/composition.jppAt a glance
- Type
- Service
- Status
- research
- Language
- Rust
- Runtime
- native CLI interpreter (Python reference implementation)
- Has code
- yes
- Has tests
- yes
Use cases and integrations
How curated lists describe it
Experimental language in which a question is a value and methods compose them, with a Python foundation and a Rust runtime, both speaking `/v1/systemone`. Every demo replays a recorded run and says what is unsettled. Chinese and English.
MrJev/awesome-jev
Frequently asked questions
What is a question value?
A typed judgment that can be passed around and composed into methods like any other value.
Can I try it without a key?
Yes, the examples replay recorded answers offline.
Which implementation should I use?
The native Rust implementation; the Python one is kept as a behaviour reference.
Related projects
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MCP serverbetaPython