PEGO
G090: Variable Read Components
Running a reachable-rule search for every rule repeatedly collects the same transitive variable reads. Dependency components compute that metadata once per recursive group.
Mechanism and Invariants
Direct reads are collected lazily; a grammar with none returns before building a graph. Callee-first strongly connected components union direct peer reads and finalized external-callee keys once, sort them and share an immutable key slice among peers. Definitions alone are not reads; recovery and Operators Rule expressions retain their conservative dependency traversal.
Scope and State
Default shared compiler metadata for all compilation/generation targets. Runtime memo keys consume the result, but matching does not run the component analysis.
Reference Control
No maintained same-source per-rule DFS comparator exists.
Evidence and Implementation
Historical record 073 measures full compilation of a 512-rule no-read chain from 10.114 to 1.003 ms and 13.414 to 1.711 MB. Read-bearing/cyclic cases have separately scoped results; other analyses and distinct transitive sets still consume work. Matching memo keys are unchanged, so compilation gains are not parser-throughput estimates.
Evidence records: 073.
Source owners: RuleVariables and dependency components.
The comparison policy distinguishes same-source controls, historical changes and full checkpoints.