Spec-ID: x07.spec.internal.x07-core@0.1.0 Status: draft Applies-to: toolchain >= v0.0.95 Related schemas: []

X07 Core (Track B): build a compiler, not a VM

X07 is an experiment in discovering programming languages optimized for LLMs to write, not for humans to read.

The feedback loop is circular:

• A language is only “good” if an LLM can reliably write correct programs in it.
• You only learn what the LLM needs by observing successes/failures across many tasks.

This repo makes that loop explicit, deterministic, and measurable.

Language and programs (Track B)

The core artifact is the compiler + its embedded language definition (versioned by lang_id).

In Track B:

• The language is defined by core built-ins plus built-in stdlib modules (no macro/rewrite layer).
• The compiler (x07c) turns the program into C source.
• The runner compiles the C source to a native executable solver artifact.
• The runner executes the solver deterministically with strict fuel + memory limits.

Seed language references:

• Guide snapshot: docs/spec/language-guide.md
• Default benchmark bundle: labs/benchmarks/bundles/regression.json
• Optional suite: labs/benchmarks/solve-pure/phase4-holdout.json

Determinism and safety

To keep fitness stable and evaluation safe:

• Evaluation uses deterministic fuel-based halting for solver runs.
• Capability access is deny-by-default and world-scoped (solve-pure, solve-fs, solve-rr, solve-kv, solve-full).
• Solver artifacts run with a fixed environment (no inherited args/env) and Unix resource limits as kill-switches.

Implementation details: docs/spec/internal/x07-c-backend.md.

Regression suites

Benchmark suites live under labs/benchmarks/ and are executed against committed reference solutions in labs/benchmarks/solutions/.

To run the default regression bundle:

• python3 labs/scripts/bench/run_bench_suite.py --suite labs/benchmarks/bundles/regression.json