Repository navigation
HermitCrab: complete cross-engine correctness controls for final-template pruning #507
Description
Final-template pruning must skip only analysis paths that cannot lead to a valid parse. This issue tracks the controls needed to demonstrate that guarantee across Machine and PanGloss.
Who is affected: users with final/non-final templates, partial words or rules, and maintainers reviewing #491 or porting its optimization.
This is a coverage gap, not a newly established Machine regression. The ten-word final-template-partial-discriminators fixture is now on Machine's conformance branch, but its passing results do not demonstrate that analysis pruning executes.
Done when: exact positive/negative identities and multiplicities survive optimized/unoptimized runs; discriminators reach the pruning branch; and claimed fixes fail when removed. Cover actual invocation role for rules shared between a stratum and a template, partial roots, lower-stratum continuations, and memoization on/off. Keep safe defaults separate from forced experimental overrides.
Published controls and remaining evidence
Commit a20bce12, through #480, adds conformance/edge-cases/final-template-partial-discriminators. Its rationale is in conformance/docs/final-template-partial-discriminators.md.
The recorded check passes all ten rows with memoization on/off. Mutating the partial-rule flag, partial-word producer, and non-final-template flag produces the predicted 2/10, 1/10, and 2/10 disagreements.
These establish synthesis/grammar sensitivity, not prune hits or fix-removed engine evidence. A zero prune count is not optimization coverage. Finite agreement does not prove universal soundness or completeness.
Related: #491 and #456. No parser code changed in this fixture update. Sparse forests and memory containment are outside scope.
Activity
johnml1135 commentedon Sep 15, 2026
Coverage update: commit a20bce1 on integrate-conformance-framework (PR #480) adds final-template-partial-discriminators. All ten rows pass with memoization on/off. Independent mutations of the partial-rule flag, partial-word producer, and non-final-template flag yield the predicted 2/10, 1/10, and 2/10 disagreements. Derivations and limitations are in conformance/docs/final-template-partial-discriminators.md. This verifies synthesis controls, not that the analysis-pruning optimization executes. Actual dual-role rules, partial roots, lower-stratum continuation and prune-hit/fix-removed evidence remain open. No parser code changed.