Module model 

The declarative rule data model.

A rule is the atomic unit the engine consumes: an identity (id, language, severity, message), a rule block describing what to match (the atomic tier: pattern snippet, kind, or regex), and an optional fix describing how to rewrite it. Relational/composite matching (#2833) and where/transform (#2834) extend this model; this module is the atomic-tier surface they build on.

Structs

Comparison

A numeric/string comparison for a Constraint.

Constraint

A where predicate on a captured metavar. Exactly one of regex / comparison / pattern / resolves_to / type is set.

ReplaceOp

Regex find/replace transform op.

ResolvedBindingConstraint

A Harn resolved-binding predicate for Constraint::resolves_to.

Rule

A single declarative rule.

RuleNode

The atomic-tier matcher. Exactly one of pattern / kind / regex must be set on a node that carries one; RuleNode::atomic resolves it.

SubstringOp

Character-slice transform op. Indices are 0-based char offsets; a negative or omitted bound clamps to the string end.

Transform

A metavar transform: read source, apply exactly one operation, bind the result under a new metavar name (the map key).

Enums

Applicability

Whether a fix may be auto-applied (clippy/ESLint machine-applicable) or is opt-in only (suggestion).

AtomicMatcher

The resolved, exactly-one atomic matcher.

ConvertOp

Case-conversion transform op.

RuleKind

What flavor of work a rule performs, derived from its shape rather than declared: a rule with a fix is a codemod; one with a message but no fix is a lint; a bare matcher is a search.

Safety

How risky a rule’s fix is, mapped onto Burin’s edit-safety taxonomy. Ordered least → most dangerous; the codemod runner auto-applies only the two safest tiers (see Safety::applicability).

Severity

Diagnostic severity. Mirrors the harn-lint vocabulary so findings can flow into the same reporting surface.

StopBy

How far a relational op (inside / has / follows / precedes) walks the tree looking for a match.

StopKeyword

The keyword forms of StopBy.