Concepts

This guide explains the terms used across the 0x0 documentation.

Source-Owned Compiler

The compiler implementation lives in .0x0 source, primarily

compiler/main.0x0. Host languages may adapt to the operating system, but they

must not own production language semantics.

Invariant: language behavior belongs in 0x0 source or checked policy data, not in

unchecked Python or shell helpers.

Seed

seed/zero.s is the stage -1 recovery seed. It can parse and evaluate enough

source and OISA to reproduce the trusted compiler chain. It is deliberately

small and is not the normal implementation home for language features.

Precondition for seed use: you are auditing or recreating the trusted root.

Normal make does not use the seed path.

OISA

OISA is the compiler output used by the self-hosting chain. The self-host gate

checks that compiling the compiler reaches a fixed point:

compiler/main.0x0 -> stage2.oisa -> stage3.oisa

Postcondition for the self-host gate: stage2.oisa and stage3.oisa are

identical.

Source Forms

0x0 source uses parenthesized symbolic forms:

• (⊙ name): module declaration;
• (↥ "path.0x0"): import;
• (↦ exported-name): export list;
• (ƒ name ...): function declaration;
• (∷ (→ Arg... Result)): type annotation;
• (doc "..."): documentation annotation;
• (cap pure): capability annotation;
• (τ Type ...): algebraic data type declaration.

See Language Guide and Syntax for exact grammar and

current restrictions.

Capabilities And Effects

Capabilities document and check whether source can perform host effects. Current

source capabilities include pure, io, file, network, process, crypto,

and hardware in the relevant checker/runtime surfaces. The beginner rule is:

pure source cannot call host effects.

Host operations are listed in runtime/host-abi.tsv and described in

Runtime Production Capabilities.

Packages

The root package manifest is 0x0.pkg. The generated lockfile is 0x0.lock.

Package imports use:

(↥ "pkg:core-option")

The compiler resolves the package name through the lockfile to a local source

path. See Packages, Package System, and

Package Registry.

Source-Owned Tooling

Production-critical tools are expected to route policy through .0x0 source.

Shell and Python adapters may perform explicit host effects such as filesystem

access, process spawning, and JSON/TSV marshaling.

See Source-Owned Tooling.

Scripting And REPL

0x0 remains a compiled language. The scripting profile adds eval, script file

execution, and REPL workflows for source-owned tooling and local inspection.

Scripting still uses the parser, capability model, stable diagnostics, and host

ABI boundary.

See Scripting And REPL.

Evidence Gates

0x0 uses Make targets and checked TSV/JSON evidence to keep claims tied to

implementation. Examples:

• make docs-check;
• make editor-check;
• make scripting-production-closure-check;
• make source-owned-tooling-closure-check;
• make selfhost-guard.

When a doc makes a production claim, it should name the source file or evidence

gate that proves it.