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

# mlab-builtins-mod

The groupant beside mlab/src/builtins/mod.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
- **status:** partial source bound model
- **source:** [`mlab/src/builtins/mod.rs`](https://github.com/ElamurAI/mova-free/blob/main/mlab/src/builtins/mod.rs)
- **source SHA-256:** `5e593db042fb0f9c…`
- **repository folder:** [`mlab/src/builtins/mod.rs.groupant`](https://github.com/ElamurAI/mova-free/tree/main/mlab/src/builtins/mod.rs.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 | [approximant](#approximant) |
| **ast** | partial | `syntax.json` |
| **composition** | partial | [composition](#composition) |
| **cost** | symbolic source derived | [invariant](#invariant) |
| **descriptant** | present | [descriptant](#descriptant) |
| **invariant** | partial | [invariant](#invariant) |
| **tests** | executed bounded checks | [tests](#tests) |

## 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 |
|---|---|---|---|
| `behavior_complement` | behavior_complement | partial source derived model | [behavior_complement](#behavior-complement) |
| `reverse_reconstruction` | reverse_reconstruction | partial source derived model | [reverse_reconstruction](#reverse-reconstruction) |
| `state_invariant` | state_invariant | partial source derived model | [state_invariant](#state-invariant) |
| `failure_precedence` | failure_precedence | partial source derived model | [failure_precedence](#failure-precedence) |
| `representation_transport` | representation_transport | partial source derived model | [representation_transport](#representation-transport) |
| `resource_cost` | resource_cost | partial source derived model | [resource_cost](#resource-cost) |

## Parts

- [mlab-builtins-mod-dimensions](https://md.groupants.elamur.ai/free/en/mova/mlab/src/builtins/mod.rs.groupant/dimensions.groupant/)

## Model text


### descriptant

#### mlab-builtins-mod

Builtin registry and shared value/shape extraction adapters used by numerical and I/O modules.

##### Modeling epoch — 2026-10-31

Prospective source read preceded edits. Bounded synthetic checks and selected existing safe tests exercise actual code; paired debug/release results and compiled negative-control assertions are retained externally. Frozen scenario, corpus, external measurement, full-school and training effects are unexecuted. Partial lexical syntax supplies no macro-expanded or semantic proof.

### approximant

#### Forward relation

register overwrites a name's function; names sorts keys; with_defaults registers eleven modules in fixed order. scalar_arg returns first real element if nonempty. dims_args ignores char values, floors positive sizes, clamps nonpositive to zero and requires trailing dimensions equal one.

##### Domain

Valid Rust value/storage invariants and available bounded resources; exact branch and effect observations only.

##### Executable approximant gap

No useful percentage-error surrogate is established for these categorical, textual or effectful observations. Supported future caps are 1%, 2%, 5%, 10%; no executable approximation or production substitution is claimed.

### invariant

#### Invariants and costs

get copies a function pointer and does not mutate registry. Invalid missing argument fails before type extraction; no matrix product allocation occurs in dims_args itself.

##### Failure ordering

NaN checked before float-to-usize conversion; +Inf saturates usize. Single-array trailing dimensions compare raw floats to one, multiargument trailing dimensions compare converted usize values.

##### Cost

Expected O(1) map lookup/insert, sorted names O(K log K); dims extraction O(arguments + trailing dimensions). Casting and downstream shape multiplication are not overflow certificates.

### composition

#### Composition

register overwrites a name's function; names sorts keys; with_defaults registers eleven modules in fixed order. scalar_arg returns first real element if nonempty. dims_args ignores char values, floors positive sizes, clamps nonpositive to zero and requires trailing dimensions equal one.

A single scalar dimension means square, no numeric arguments means 1x1, empty dimension vector means 0x0. default_dim chooses rows unless rows==1; dim_arg absent/empty/char yields None.

##### dimensions

Filter char values, dispatch by numeric argument count, map dimensions with NaN rejection then clamp/floor/saturating cast; constrain higher dimensions to one.

Boundary: The helper returns a pair only and does not allocate the requested matrix.

##### Interaction limit

Local fragment relations compose only with valid Value storage, caller error propagation and delegated providers. They do not establish whole-interpreter or host-filesystem guarantees.

### models

## Typed models — mlab-builtins-mod

Source-derived partial relations; finite checks do not prove universality.

### behavior_complement

names excludes hash iteration nondeterminism in its returned order. scalar_arg excludes rejecting a nonempty nonscalar solely for its size. NaN dimension excludes a successful dims_args result.

### reverse_reconstruction

Registry snapshot admits arbitrary overwritten registrations and insertion permutations with same final bindings. Dimensions admit fractional/negative antecedents after floor/clamp and arbitrary skipped char arguments.

### state_invariant

get copies a function pointer and does not mutate registry. Invalid missing argument fails before type extraction; no matrix product allocation occurs in dims_args itself.

### failure_precedence

NaN checked before float-to-usize conversion; +Inf saturates usize. Single-array trailing dimensions compare raw floats to one, multiargument trailing dimensions compare converted usize values.

### representation_transport

A single scalar dimension means square, no numeric arguments means 1x1, empty dimension vector means 0x0. default_dim chooses rows unless rows==1; dim_arg absent/empty/char yields None.

### resource_cost

Expected O(1) map lookup/insert, sorted names O(K log K); dims extraction O(arguments + trailing dimensions). Casting and downstream shape multiplication are not overflow certificates.

### tests

#### Evidence and limitations

Selected named outcomes: builtins::wave30_tests::registry_and_dimensions. Each ran twice debug and twice release with sorted identical nonempty outcomes and numeric exit 0. Source-specific compiled control exercised "builtins::wave30_tests::registry_and_dimensions": compile exit 0, assertion-red exit 101, exact-restored rerun exit 0. External receipts: octopus-wave30-io-2026-10-31 (native-commands.json, positive-receipts.json, controls.json).

Scope: get copies a function pointer and does not mutate registry. Invalid missing argument fails before type extraction; no matrix product allocation occurs in dims_args itself.


AST projection generated twice to fresh files and compared byte-for-byte. Runtime evidence is finite and does not establish every branch, allocation failure, backend implementation or effect path. No optimization or speed claim.