---
title: "prag-schema-codec — Mova code model"
description: "Mova code model of prag/src/schema.rs: components with their labels, obernants and the model text."
url: "https://groupants.elamur.ai/free/en/mova/prag/src/schema.rs.groupant/codec.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/prag/src/schema.rs.groupant/codec.groupant/>

# prag-schema-codec

The groupant beside prag/src/schema.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:** [`prag/src/schema.rs`](https://github.com/ElamurAI/mova-free/blob/main/prag/src/schema.rs)
- **source SHA-256:** `7dade219cf710dd0…`
- **covers:** Label parse and row transport (bytes 4725–6473)
- **part of:** [prag-schema](https://md.groupants.elamur.ai/free/en/mova/prag/src/schema.rs.groupant/)
- **repository folder:** [`prag/src/schema.rs.groupant/codec.groupant`](https://github.com/ElamurAI/mova-free/tree/main/prag/src/schema.rs.groupant/codec.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 |
|---|---|---|---|
| `prag-schema-codec-behavior-complement` | behavior_complement | partial source model | [behavior-complement](#behavior-complement) |
| `prag-schema-codec-reverse-reconstruction` | reverse_reconstruction | partial source model | [reverse-reconstruction](#reverse-reconstruction) |
| `prag-schema-codec-coupling` | constraint_relation | partial source model | [coupling](#coupling) |

## Model text


### forward

Parse requires exactly seven columns then validates trimmed values in fixed order. Bits are exactly 0 or 1 after trim. Means is trimmed, nonempty, <=30 split_whitespace words; internal spacing is preserved. labels_tsv writes all fields joined by TAB and does not escape or validate means.

### behavior-complement

Over columns and Result<Labels,String>, exclude success whenever any validation predicate fails; exclude a later-field error when an earlier field is invalid. TSV outputs with escaped or normalized means are absent: writer copies it verbatim. This model does not assert arbitrary labels are safe TSV rows.

### reverse-reconstruction

All edge-whitespace variants of a valid column tuple share one parsed Labels. An error prefix fixes the first invalid position but leaves later columns unrestricted and earlier ones merely valid. Different over-limit texts can share the same word-count error; actual input cannot be recovered from an error.

### invariant

Transport roundtrip is exact for D from the parent. Counterfactual accepting 30 words with >= instead of > rejects the boundary witness. Fields supplied directly can contain TAB/newlines; row-level callers must maintain D. Serde roundtrip has no 30-word gate.

### coupling

Transport roundtrip is exact for D from the parent. Counterfactual accepting 30 words with >= instead of > rejects the boundary witness. Fields supplied directly can contain TAB/newlines; row-level callers must maintain D. Serde roundtrip has no 30-word gate.

### composition

The closed table, coordinate and codec fragments share exact enums and field order. Classifier indices require the corresponding classes list; schema is not directly used by infer.rs. Agree uses string tables and does not validate this schema. Native tests exercise schema operations; caller inspection is not an executed cross-file join.

### cost

O(total inspected bytes) parsing with short-circuit validation; means allocation proportional to its trimmed bytes; O(output bytes) TSV.

### checks

Six wave13_models tests plus one prior schema test run twice per debug/release profile; evidence.md at the file root binds receipts. Literal independent tables cover 4608 categorical rows, 34 valid coordinate updates, 12 invalid boundaries, 127 first-error masks, five word counts and Unicode whitespace fibers. JSON coverage executes Form variants and default Labels; arbitrary serde error cases are untested.

### epoch-memory

2026-10-30: prospective model recorded before edits. Old Boolean class 2 silently overwrote true with false; invalid_class_panics_before_mutation failed. The narrow guard preserves unit return and valid indices, consistently panicking before mutation. The prospective note estimated 36 valid classes; actual table sum is 34. The word-limit > to >= production mutant compiles and is rejected by rejection_order_and_word_boundary, then exact source is restored. No escaping/API redesign was introduced: noncanonical means remains an explicit transport limit. Syntax generation repeats exactly; macro bodies remain opaque, although methods are exercised natively. No live parser, teacher, corpus, network, GPU, training, filesystem-durability or full-system claim.