Configuration model

Ibex keeps reproducible grammar intent in the grammar and keeps environment or review choices at the invocation boundary. This separation prevents a build flag from silently changing a source-owned parser contract.

Grammar-owned settings

Declare settings in an extended grammar when every consumer should observe the same choice:

class ExampleParser
pragma extended
parser
  algorithm ielr
  entries isolated
end

The current grammar-owned parser block supports slr, lalr, ielr, or lr1 construction and shared or isolated entry handling. The declaration is part of normalized Grammar IR and is visible in generated reports.

Invocation-owned settings

Keep these choices at the CLI or API call site because they describe a local operation rather than the grammar's meaning:

output path and embedded-runtime selection (-o, -E);
table representation and diagnostic format;
warnings, verification strictness, resource budgets, and report output;
a temporary analysis algorithm used for comparison or investigation; and
external command execution for explicitly unsafe fuzz or reduction workflows.

An invocation may select an analysis algorithm, but it must report that the selection is noncanonical when it differs from the grammar declaration. A conflicting canonical selection is rejected at the declaration location.

Review checklist

When adding a setting, ask:

Would two independent users of the same grammar need the same value? If so,

it is grammar-owned.

Is the value about this run, host, output, or evidence capture? If so, it is

invocation-owned.

Does changing it alter generated parser behavior, persisted IR, or runtime

ABI? Update the relevant schema, fixture, maturity entry, and migration note.

Is the setting opt-in? Keep the compatible default unchanged and document

the activation boundary next to the option.

See the stability policy, grammar reference, and development guide for contract and verification rules.