Boundary

Boundary is a Zig compiler for portable, defunctionalized algebraic effects. It compiles a typed source program into one program-specific Boundary Machine:

typed source -> Control IR -> RNF -> direct reducer -> Machine ABI v2

The Machine is the sole executable meaning of a Boundary program. Its canonical ABL_RNF2 state contains a bounded stack of program-specific continuation constructors and their exact future-live environments. It contains no generic instruction cursor, local-slot table, condition history, runtime module, or native callback.

Public surface

• boundary.effect declares typed residual effect sites.
• boundary.schema exposes canonical portable-value codecs.
• boundary.ir exposes advanced typed source/control authoring.
• boundary.program declares a source program.
• boundary.Driver drives the compiled Machine locally.
• boundary.Agent is an optional profile over the same compiler.
• boundary.Bytes, boundary.Text, and boundary.Vector are bounded portable values.

The primary construction is:

const Program = boundary.program("research-agent", Body);

const Machine = Program.compile(.{
    .state_encoding = .rnf_v1,
    .maximum_frames = 64,
    .maximum_state_bytes = 1 << 20,
    .maximum_machine_fuel = 1_000_000,
    .debug_metadata = false,
});

Machine exposes ABI version 2, typed arguments/results/effects, deterministic fuel semantics, transactional step and resume operations, and canonical state encoding. Local execution and World execution both drive this same Machine.

Portable language

Boundary admits explicit fixed-width integers, booleans, products, exhaustive enums, tagged unions, optionals, fixed arrays, and bounded Bytes(MaxBytes), Text(MaxBytes), and Vector(T, MaxItems) values. Pointer identity, target-width integers, floats, host handles, arbitrary callbacks, and unbounded collections are outside the portable language.

Residual effects are statically known and typed. Boundary compiles known control, helper, loop, and local after semantics into RNF; only genuine external authority crosses the Machine boundary.

Documentation

• Program authoring
• Compiler pipeline
• Resumption Normal Form
• Machine ABI
• Machine state
• Portable values
• Effects
• World integration
• Migration from Boundary 0.7

Proof

Run the aggregate proof:

zig build check --summary all

Focused gates include check-boundary-machine, check-boundary-rnf, check-boundary-rnf-values, check-boundary-rnf-control, check-boundary-rnf-recursion, check-boundary-rnf-after, check-boundary-machine-state, check-boundary-machine-malformed, check-boundary-machine-native-wasm, check-boundary-machine-no-interpreter, and check-boundary-machine-deletion. The aggregate also runs the real v0.7 performance comparison and emits the Boundary-owned completion fields through check-boundary-machine-receipt.

The aggregate is a release-owner gate and its historical performance lane requires a tagged Boundary checkout with local .git metadata and the reviewed v0.7.0 tag. Extracted package consumers can run the focused current-version gates, but a package without repository history cannot authenticate or claim the immutable v0.7 comparison.

Boundary 1.0 is source- and state-incompatible with Boundary 0.7. The immutable 0.7 release remains the compatibility implementation; Boundary 1.0 contains no legacy runtime or automatic continuation migration.