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

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# mlab-lexer

The groupant beside mlab/src/lexer.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/lexer.rs`](https://github.com/ElamurAI/mova-free/blob/main/mlab/src/lexer.rs)
- **source SHA-256:** `ac652c6bc998f3fe…`
- **repository folder:** [`mlab/src/lexer.rs.groupant`](https://github.com/ElamurAI/mova-free/tree/main/mlab/src/lexer.rs.groupant)
- **repository commit:** `48f2e6f74146`

> **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) |
| `representation_transport` | representation_transport | partial source derived model | [representation_transport](#representation-transport) |
| `failure_precedence` | failure_precedence | partial source derived model | [failure_precedence](#failure-precedence) |
| `resource_domain` | resource_domain | partial source derived model | [resource_domain](#resource-domain) |
| `interaction_relation` | interaction_relation | partial source derived model | [interaction_relation](#interaction-relation) |

## Parts

- [mlab-lexer-quote-context](https://md.groupants.elamur.ai/free/en/mova/mlab/src/lexer.rs.groupant/quote-context.groupant/)

## Model text


### descriptant

#### Context-sensitive tokenization

lex scans Unicode chars, maintains one-based line/char-column, whitespace-before flag and delimiter stack. Numbers normalize D exponent for parsing and imaginary suffix j/J/I to i spelling. Apostrophe after a value is Quote except whitespace in matrix/cell context, where it starts Str. Newline is emitted; ... consumes remainder and newline. EOF token always appended.

##### Modeling epoch 2026-10-31

Prospective source reading precedes test additions. Retained observations: parser consumes Newline, space_before and token tags, so dropping spacing changes [1 -2] and [1 - 2]. AST Num/Imag carry original/normalized spelling; coordinate changes alter diagnostics.

This is partial source-derived modeling, not proof, full semantic coverage, or a performance result. Public malformed representations, unbounded allocations and exhaustive numerical edge cases remain outside the checked fixtures.

### approximant

#### Context-sensitive tokenization forward relation

lex scans Unicode chars, maintains one-based line/char-column, whitespace-before flag and delimiter stack. Numbers normalize D exponent for parsing and imaginary suffix j/J/I to i spelling. Apostrophe after a value is Quote except whitespace in matrix/cell context, where it starts Str. Newline is emitted; ... consumes remainder and newline. EOF token always appended.

Domain: UTF-8 strings, finite memory; no external effects. Mixed delimiter stack pops are permissive. Block marker recognition requires trimmed whole line at line start.

No executable Rust surrogate is supplied: categorical decisions require exact observations; numerical kernels have no measured approximation metric here. Future supported caps are 1%, 2%, 5%, 10% only.

### invariant

#### Invariant and cost

Coordinates count chars, not UTF-8 bytes. EOF exists even for empty input. Newlines inside parentheses remain tokens despite the file header's stale whitespace description. Numeric overflow may produce nonfinite f64; no finite-value guarantee.

Cost: O(C+token text) ordinary scan and O(C+T+depth) memory; line_rest allocates trimmed lines for block comments. No source-size cap.

Failure ordering: Whitespace/comment/continuation processing precedes token detection; numeric detection precedes identifier detection; contextual apostrophe precedes generic operators. First encountered literal/invalid-character error returns its opening/current position.

### composition

#### Parent composition

parser consumes Newline, space_before and token tags, so dropping spacing changes [1 -2] and [1 - 2]. AST Num/Imag carry original/normalized spelling; coordinate changes alter diagnostics.

Scoped fragments are projections over exact byte intervals in this source; they share one parent syntax projection. Uncovered declarations and embedded checks remain parent modeled. Whitespace/comment/continuation processing precedes token detection; numeric detection precedes identifier detection; contextual apostrophe precedes generic operators. First encountered literal/invalid-character error returns its opening/current position.

The relation is source-derived and finite checks cannot establish complete correctness or a composition-wide numerical error bound.

### models

### behavior_complement

Accepted token sequences exclude treating [a 'x']'s spaced quote as transpose, or a' as a string opener. Unterminated strings exclude Ok; invalid characters exclude tokens past the error. Scanner does not reject unmatched delimiters or unterminated block-comment EOF; these are not lexer validation guarantees.

### reverse_reconstruction

For tokens T, preimage is all Unicode strings whose contextual scan yields T including retained locations/space flags. Comments, quote escapes and normalized imaginary suffixes can collapse. Removing coordinate observations enlarges fibers further; token text is not an exact inverse source serializer.

### representation_transport

Coordinates count chars, not UTF-8 bytes. EOF exists even for empty input. Newlines inside parentheses remain tokens despite the file header's stale whitespace description. Numeric overflow may produce nonfinite f64; no finite-value guarantee.

### failure_precedence

Whitespace/comment/continuation processing precedes token detection; numeric detection precedes identifier detection; contextual apostrophe precedes generic operators. First encountered literal/invalid-character error returns its opening/current position.

### resource_domain

UTF-8 strings, finite memory; no external effects. Mixed delimiter stack pops are permissive. Block marker recognition requires trimmed whole line at line start.

### interaction_relation

parser consumes Newline, space_before and token tags, so dropping spacing changes [1 -2] and [1 - 2]. AST Num/Imag carry original/normalized spelling; coordinate changes alter diagnostics.


### tests

#### Source-specific bounded evidence

`lexer::wave30::context`: matrix quote versus transpose, normalized imaginary suffix, continuation coordinates, emitted parenthesized newline, unterminated string, EOF.

Seven named tests each passed twice debug and twice release on 2026-10-31, with actual named log lines sorted and identical across all four runs (28 selected successful executions). Each source has a compiled changed-assertion negative control; six runtime sources additionally have compiled production-body mutants that fail those unchanged tests. AST has representation evidence only. Every mutant is byte-restored and its positive test rerun. See `evidence.json` for this source's exact hash, mutation and exit statuses. External receipts retain full logs, command metadata, control records and prospective notes.

Unexecuted here: No exhaustive Unicode, block-comment or numeric scan coverage. No corpus, GPU, live filesystem, timer or callback run. No broad Clippy claim; dependency/style checks were not repeated. Only appended test blocks were rustfmt-formatted; original production bytes are unchanged.