Elamur Groupantsworld-treeread-numeric
The groupant beside world/src/treeread.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 source model | forward |
| ast | partial | ../syntax.json |
| composition | partial source model | composition |
| cost | partial source model | cost |
| descriptant | partial source model | epoch-memory |
| invariant | partial source model | invariant |
| tests | partial source model | 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-treeread-numeric-behavior-complement | behavior_complement | partial source model | behavior-complement |
world-treeread-numeric-reverse-reconstruction | reverse_reconstruction | partial source model | reverse-reconstruction |
world-treeread-numeric-boundary | constraint_relation | partial source model | boundary |
Model text
forward
Scope: lemma and num. Lowercase lemma; remove commas and dollar signs from form, parse f64, admit integral values, cast to i64. POS admission occurs in the reading child, not here.
invariant
For small exactly representable finite integers, normalized decimal values are preserved. Fractional values and NaN/infinity fail the fractional-part predicate. This is not a general exact-i64 parser.
cost
O(form bytes) allocation/filter plus floating parser; lowercasing scales with Unicode output bytes. No performance measurement.
behavior-complement
A finite noninteger value cannot become Some through this predicate. Numeric-looking lemma with a nonnumeric form is not enough. Misplaced commas or dollar signs are not rejected structurally.
reverse-reconstruction
1200 admits 1,200, $1200, 12e2 and 1200.0 among many surfaces. Casting also loses precision outside small exact values; no unique surface recovery is possible.
boundary
f64 parsing plus saturating cast differs from checked integer parsing near i64 limits. The oracle domain is deliberately small; malformed currency syntax is not validated.
composition
Reading subsequently filters POS, attaches noun and verb and adds context. A valid numeral alone says nothing about the counted unit or holder.
checks
integral_number_surface_fibers exercises four 1200 forms, negative integer, fraction, NaN, infinity and word rejection. It calls real num without annotation.
epoch-memory
2026-10-30: preserve existing float semantics rather than invent an exact-number claim. Partial syntax projection only; approximation error metric for semantic interpretation absent.
This page in Markdown → https://md.groupants.elamur.ai/free/en/mova/world/src/treeread.rs.groupant/numeric.groupant/