---
title: "answer-span-extraction — Mova code model"
description: "Mova code model of world/src/span.rs: components with their labels, obernants and the model text."
url: "https://groupants.elamur.ai/free/en/mova/world/src/span.rs.groupant/extraction.groupant/"
---
Elamur: [Mova](https://md.mova.elamur.ai/free/en/) · [Dictionary](https://md.dictionary.elamur.ai/free/en/) · [Research](https://md.research.elamur.ai/free/en/) · **Groupants**

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# answer-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

- **kind:** groupant_fragment
- **status:** partial source bound model
- **source:** [`world/src/span.rs`](https://github.com/ElamurAI/mova-free/blob/main/world/src/span.rs)
- **source SHA-256:** `4d215ccd57884f41…`
- **covers:** Source scope beginning pub fn extract(t: &Tree, want: Want, preds: &[String], sub_preds: &[String], fr: &QFrame, qlem: &HashSet<String>) -> Option<(String, String)> {; selected node envelope, partial semantic coverage. (bytes 9139–29268)
- **part of:** [answer-span](https://md.groupants.elamur.ai/free/en/mova/world/src/span.rs.groupant/)
- **repository folder:** [`world/src/span.rs.groupant/extraction.groupant`](https://github.com/ElamurAI/mova-free/tree/main/world/src/span.rs.groupant/extraction.groupant)
- **repository commit:** `855da7bd4a7b`

> **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](#forward) |
| **ast** | partial | `../syntax.json` |
| **composition** | partial source model | [composition](#composition) |
| **cost** | partial source model | [cost](#cost) |
| **descriptant** | partial source model | [epoch-memory](#epoch-memory) |
| **invariant** | partial source model | [invariant](#invariant) |
| **tests** | partial source model | [checks](#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](#behavior-complement) |
| `answer-span-extraction-reverse-reconstruction` | reverse_reconstruction | partial source model | [reverse-reconstruction](#reverse-reconstruction) |
| `answer-span-extraction-child-order` | priority_relation | partial source model | [child-order](#child-order) |
| `answer-span-extraction-global-selection` | constraint_relation | partial source model | [global-selection](#global-selection) |

## Parts

- [answer-span-why](https://md.groupants.elamur.ai/free/en/mova/world/src/span.rs.groupant/extraction.groupant/why.groupant/)
- [answer-span-clauses](https://md.groupants.elamur.ai/free/en/mova/world/src/span.rs.groupant/extraction.groupant/clauses.groupant/)

## 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.