Rule Semantics

Evaluation Pipeline

1. Parse Locy program.
2. Build dependency graph.
3. Validate types/schema compatibility.
4. Stratify rules.
5. Evaluate each stratum to fixpoint.
6. Execute command phase (QUERY, DERIVE, EXPLAIN, ABDUCE, ASSUME body).

Overloaded Rules

Multiple CREATE RULE clauses sharing one name define one logical relation. Clauses can be prioritized where supported.

Negation Rules

IS NOT requires stratification-safe dependencies. Cyclic negation is rejected at compile time.

Monotonic Recursion

Recursive aggregation requires monotonic operators where specified. Non-monotonic recursive shapes are rejected.

Determinism

BEST BY can use deterministic tie-breaking through config (deterministic_best_by = true).

Limits and Guardrails

Key guardrails come from LocyConfig:

• max_iterations
• timeout
• max_derived_bytes
• max_explain_depth
• max_slg_depth

See Errors & Limits for operational guidance.