---
title: "world-schooltools-parsing-key-fields — Mova code model"
description: "Mova code model of world/src/schooltools.rs: components with their labels, obernants and the model text."
url: "https://groupants.elamur.ai/free/en/mova/world/src/schooltools.rs.groupant/parsing.groupant/key-fields.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**

This page as HTML: <https://groupants.elamur.ai/free/en/mova/world/src/schooltools.rs.groupant/parsing.groupant/key-fields.groupant/>

# world-schooltools-parsing-key-fields

The groupant beside world/src/schooltools.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/schooltools.rs`](https://github.com/ElamurAI/mova-free/blob/main/world/src/schooltools.rs)
- **source SHA-256:** `22ec16d5488a88c1…`
- **covers:** Trim line, reject leading #, split at first colon, trim key, accept exactly exercise/test/exam. Split value at every | and trim each field, retaining empty fields and arbitrary width. (bytes 3281–3559)
- **part of:** [world-schooltools-parsing](https://md.groupants.elamur.ai/free/en/mova/world/src/schooltools.rs.groupant/parsing.groupant/)
- **repository folder:** [`world/src/schooltools.rs.groupant/parsing.groupant/key-fields.groupant`](https://github.com/ElamurAI/mova-free/tree/main/world/src/schooltools.rs.groupant/parsing.groupant/key-fields.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 |
|---|---|---|---|
| `world-schooltools-parsing-key-fields-behavior-complement` | behavior_complement | partial source model | [behavior-complement](#behavior-complement) |
| `world-schooltools-parsing-key-fields-reverse-reconstruction` | reverse_reconstruction | partial source model | [reverse-reconstruction](#reverse-reconstruction) |
| `world-schooltools-parsing-key-fields-first_colon` | delimiter_relation | partial source model | [first_colon](#first-colon) |
| `world-schooltools-parsing-key-fields-empty_field_retention` | shape_relation | partial source model | [empty_field_retention](#empty-field-retention) |
| `world-schooltools-parsing-key-fields-key_case` | domain_boundary | partial source model | [key_case](#key-case) |
| `world-schooltools-parsing-key-fields-borrowed_projection` | information_loss | partial source model | [borrowed_projection](#borrowed-projection) |

## Model text


Wave34, 2026-10-31. Source-bound helper model; no universal proof or approximation-error certificate. Historical parent epoch remains intact.

### forward

Trim line, reject leading #, split at first colon, trim key, accept exactly exercise/test/exam. Split value at every | and trim each field, retaining empty fields and arbitrary width.

### invariant

Recognized malformed option lines remain Some; this parser does not enforce five fields or one answer marker. Returned slices borrow original text.

### cost

O(B+F) scanning/vector storage for B bytes and F fields; no copied field strings.

### composition

Parsing precedes canon in tally/lint/edit. Lint separately emits tabs on all lines before recognizing option lines; parse refusal does not suppress that nonoption diagnostic.

### behavior-complement

Exclude recognition of comments, uppercase Test and fact keys; exclude splitting key/value at a later colon; exclude dropping empty fields between adjacent bars. Recognition is not content validity.

### reverse-reconstruction

For observed (key,fields), compatible lines include any surrounding/field whitespace with the same trimmed slices, plus colons within values. None includes no colon, comments and every unrecognized key. Whitespace and its byte positions are lost.

### first_colon

Only first colon separates the kind; subsequent colons are ordinary value characters until bar splitting.

### empty_field_retention

A recognized value with m bars returns m+1 fields, including leading/trailing/adjacent empty values; even no bar returns one field.

### key_case

Three literal lowercase keys after trimming are admitted; case folding is absent. Comment recognition precedes colon lookup.

### borrowed_projection

Field strings are trim-normalized borrowed slices; parser output cannot recover indentation or spacing around bars without retaining the original input.

### checks

Exact world library selections: schooltools::wave9_models::parser_canonical_fibers_and_tally. Current repeated debug/release outcomes and compiled controls are in the root sidecar wave34-evidence.md. Only these supplied-input tests are current evidence; older parent module-wide receipts are historical. Macro bodies remain opaque.

### epoch-memory

Prospective model saved before edits. This epoch deepens one existing node rather than renaming it. Production implementation unchanged; tests add helper-boundary observations where stated. No live lessons, frozen suites, model loading, teacher or network. Read-only symbolic relations are broader than the finite native domain.