Extend the Azure Policy parser to handle complete policyRule and
policyDefinition JSON structures, not just standalone constraints.
Policy rule parser (policy_rule.rs):
- Parse top-level { "if": ..., "then": ... } objects
- Extract effect kind (deny, audit, append, modify, etc.) into typed AST
- Parse "details" structurally when it is an object to pull out
existenceCondition as a first-class Constraint; fall back to opaque
JSON for non-object details (e.g. append array form)
- Detect duplicate/missing keys for "if", "then", "effect", "details"
Policy definition parser (policy_definition.rs):
- Handle both wrapped ARM envelope ({ "properties": { ... } }) and
unwrapped (properties-level keys at top level) forms
- Type-extract displayName, description, mode, metadata, parameters,
and policyRule; everything else goes into extra
- Parse parameter definitions with type, defaultValue, allowedValues,
and metadata; detect duplicate parameter names
- Duplicate key detection throughout
Grammar documentation (docs/azure-policy/azurepolicy.ebnf):
- Add formal EBNF grammar covering policy-rule, then-block,
constraints, conditions, all 19 operators, count expressions,
JSON values, and ARM template expressions
Test harness changes:
- Add parse_level field to YAML test cases: "constraint" (default),
"policy_rule", or "policy_definition"
- Un-skip three parse_errors cases that needed policy_rule-level parsing
- Add policy_rule.yaml with 12 cases covering all 9 effect kinds,
existenceCondition, parameterized effects, complex conditions, and
extra key handling
- Add policy_definition.yaml with wrapped, unwrapped, parameterized,
missing-policyRule, and duplicate-key error cases
