Elamur Groupantsmlab-lexer-quote-context
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
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 |
| ast | partial | ../syntax.json |
| cost | symbolic source derived | invariant |
| descriptant | present | descriptant |
| invariant | partial | invariant |
| tests | executed bounded checks | 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 |
reverse_reconstruction | reverse_reconstruction | partial source derived model | reverse_reconstruction |
representation_transport | representation_transport | partial source derived model | representation_transport |
failure_precedence | failure_precedence | partial source derived model | failure_precedence |
resource_domain | resource_domain | partial source derived model | resource_domain |
interaction_relation | interaction_relation | partial source derived model | interaction_relation |
Model text
descriptant
Quoted literal versus transpose
At apostrophe compute prev_value from last token and in_matrix from top delimiter. Quote iff prev_value && !(space_before && in_matrix); otherwise decode single quote string, doubling apostrophes. Double quote decodes known backslash escapes and doubled quotes.
Modeling epoch 2026-10-31
Prospective source reading precedes test additions. Retained observations: Str becomes AST Str, Quote becomes postfix CTranspose. parser matrix spacing must consume the unchanged space_before flag.
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
Quoted literal versus transpose forward relation
At apostrophe compute prev_value from last token and in_matrix from top delimiter. Quote iff prev_value && !(space_before && in_matrix); otherwise decode single quote string, doubling apostrophes. Double quote decodes known backslash escapes and doubled quotes.
Domain: UTF-8 input and scanner state at string branch; no evaluation or file effects.
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
Literal error points to opening column; single-quote payload marks false, double-quote true. Context stack influences classification but is not delimiter validation.
Cost: O(literal chars), O(decoded chars) allocation.
Failure ordering: Previous-value discrimination precedes string consumption; doubled quote precedes closing-quote branch; recognized backslash escapes consume two chars.
models
behavior_complement
For a previous identifier a, a' excludes Str while [a 'x'] excludes Quote at the spaced opener. Newline/EOF before closing quote excludes successful literal.
reverse_reconstruction
Decoded single quote x has all escaped source spellings producing x in a non-transpose context; output Quote requires preceding value and absence of spaced matrix condition. Original escape spelling cannot be reconstructed uniquely.
representation_transport
Literal error points to opening column; single-quote payload marks false, double-quote true. Context stack influences classification but is not delimiter validation.
failure_precedence
Previous-value discrimination precedes string consumption; doubled quote precedes closing-quote branch; recognized backslash escapes consume two chars.
resource_domain
UTF-8 input and scanner state at string branch; no evaluation or file effects.
interaction_relation
Str becomes AST Str, Quote becomes postfix CTranspose. parser matrix spacing must consume the unchanged space_before flag.
tests
Bounded evidence
Selected actual-code Rust test: lexer::wave30::context with cargo test --offline --locked -p mlab --lib. CPU synthetic fixtures only. Two debug and two release runs, sorted named outcomes, numeric statuses, compiled assertion controls and exact source restoration are retained externally under the wave30 expressions receipt directory. The source-to-test map distinguishes runtime semantics from AST representation checks. This fragment shares the parent test: only the exercised branches are observed; its whole prose is not runtime coverage. No corpus, GPU, live filesystem inspection, callbacks, RNG shuffle or wall-clock execution.
Syntax is generated twice from exact source and compared. Lexical projection has no expansion/type/name resolution. No strict Clippy claim; existing dependency/style findings are not re-run merely for repetition.
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