Elamur Groupantsanswer-span-extraction
The groupant beside world/src/span.rs in the Mova repository: what the code computes, what it never does, how to go back from its outputs, its invariants, cost and checks.
Facts
Implementation material. A Mova code model describes this code at one source revision: partial models, finite checks and their stated scope. It is not a reviewed general exposition, and its labels are shown as written, never raised.
Components
| component | label | where |
|---|---|---|
| approximant | partial source model | forward |
| ast | partial | ../syntax.json |
| composition | partial source model | composition |
| cost | partial source model | cost |
| descriptant | partial source model | epoch-memory |
| invariant | partial source model | invariant |
| tests | partial source model | checks |
Obernants
The typed relations around the forward model: the behaviour complement (what the code never does), the reverse reconstruction (every input compatible with an output) and specialised views.
| id | type | label | where |
|---|---|---|---|
answer-span-extraction-behavior-complement | behavior_complement | partial source model | behavior-complement |
answer-span-extraction-reverse-reconstruction | reverse_reconstruction | partial source model | reverse-reconstruction |
answer-span-extraction-child-order | priority_relation | partial source model | child-order |
answer-span-extraction-global-selection | constraint_relation | partial source model | global-selection |
Parts
Model text
Subject: world/src/span.rs, whole-file SHA-256 in manifest, baseline 4279da541. Domain: finite acyclic valid trees with consistent child lists, valid indices and terminating dependencies. Observation: a single call return, not semantic truth or reachability. Hold Tree, ans::lemmas and types::FEELING dependencies fixed; parser/model loading and external caller wiring are gaps. All entries are source-derived partial models. Exact-target definitions are not executable inverses; finite tests cannot establish universal correspondence.
forward
Ordered dispatch, shared clean/text closure, numeric exception; Why and clauses are refined children.
invariant
Borrowed inputs unchanged; no semantic truth claimed.
cost
Repeated helper work; overlapping child scopes are not additive costs.
epoch-memory
2026-10-29: initial source-bound epoch. Preserve Num bypass, global Feel selection, early-return cleanup suppression, and verb_kids comment mismatch: code expands Xcomp only and checks no shared subject. No source changes or task-accuracy claim. Partial syntax has no semantic analysis or macro expansion.
checks
Structural inventory checks hashes, references, types and node bounds only. Proposed oracle: enumerate small annotated acyclic trees and compare literal expected returns, including None and labels; mutate priority or echo inequality to obtain a red control. Any executed bounded evidence is recorded separately in root evidence.md; catalog examples remain proposed until recorded there.
composition
Children share immutable Tree and question state. Routing yields Want, predicate selection yields p, dispatch yields candidate indices, normalization yields text; Num bypasses normalization. Guarded branches compose as a union, sequential stages via existential intermediates. Reverse keeps all compatible intermediates; complement is this node's U minus composed R, not union of child complements. Why/clauses overlap extraction. minus_question is separate API and caller wiring is outside file. Do/Clause delegation falls through after After None but most direct branch returns stop on clean None.
behavior-complement
U=full valid extract calls x optional (text,rule); R=extract. Inner U minus R contains Some on empty input and branch-impossible labels. After immediate return out, later branch outputs are excluded even if returned value is None.
Assumptions/evidence/status: common domain above; source-derived partial relation at bound revision. Approximation and held-fixed inputs are stated in the relation. Oracle: finite literal fixtures exercising both membership and nonmembership against the actual function, preserving ambiguous preimages. No linguistic correctness or universal proof inferred.
reverse-reconstruction
Union compatible Wants, anchors, candidates and cleaning fibers; retain intermediate p and index lists existentially. None combines absent candidates and rejected candidates; shared rule labels do not identify unique branches.
Assumptions/evidence/status: common domain above; source-derived partial relation at bound revision. Approximation and held-fixed inputs are stated in the relation. Oracle: finite literal fixtures exercising both membership and nonmembership against the actual function, preserving ambiguous preimages. No linguistic correctness or universal proof inferred.
child-order
verb_kids concatenates direct children then children of each direct Xcomp, no Conj expansion or shared-subject test despite comment. Obj tries Obj,Ccomp,Xcomp,Iobj; skips pronoun-only matches but stops on non-pronoun cleanup failure.
Assumptions/evidence/status: common domain above; source-derived partial relation at bound revision. Approximation and held-fixed inputs are stated in the relation. Oracle: finite literal fixtures exercising both membership and nonmembership against the actual function, preserving ambiguous preimages. No linguistic correctness or universal proof inferred.
global-selection
Num/Feel scan globally. Where has global fallback; When global scan only without predicate. Say needs p but selects first quote pair globally, not speech attached to p. Anchor association is a heuristic gap.
Assumptions/evidence/status: common domain above; source-derived partial relation at bound revision. Approximation and held-fixed inputs are stated in the relation. Oracle: finite literal fixtures exercising both membership and nonmembership against the actual function, preserving ambiguous preimages. No linguistic correctness or universal proof inferred.
This page in Markdown → https://md.groupants.elamur.ai/free/en/mova/world/src/span.rs.groupant/extraction.groupant/