roundtrip-block-reporting-numeric-projections

The groupant beside tools/roundtrip/src/blocks/run.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-and-cost
descriptant	present	descriptant
invariant	partial	invariant-and-cost
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
`layer_filter`	layer_filter	partial source derived model	layer_filter
`meta_complement`	meta_complement	partial source derived model	meta_complement
`missing_cell`	missing_cell	partial source derived model	missing_cell
`finite_sum`	finite_sum	partial source derived model	finite_sum

Model text

descriptant

Description and epoch memory

per handles zero; lbits sums requested layer excluding Meta; cbits returns zero if absent; total_bits sums LAYERS; rbits selects exact Meta predicate and optional layer.

Epoch 2026-10-31

Prospective model retained externally before edits. Existing production bytes preserved; only bounded inline tests appended to six owned files. Models distinguish byte reconstruction with residual from semantic understanding and persistent learning. Finite tests and compiled mutants support selected boundaries only. Source inspection identified noninjective projections and explicit admissibility restrictions; no bug repair or performance claim.

Combiner input is this source snapshot, syntax projection, models, costs and retained receipts. Proposed next epoch: target the stated unexecuted branches with bounded witnesses before expanding any claim. AST remains partial, macros opaque; no name resolution or proof.

approximant

Forward relation

per handles zero; lbits sums requested layer excluding Meta; cbits returns zero if absent; total_bits sums LAYERS; rbits selects exact Meta predicate and optional layer.

Domain: Finite residual f64 and representable integer counts; volume exact_ok<=volumes for report subtraction. Private helper tests supply synthetic data; model, corpus and report-write CLI paths not executed.

No executable percentage surrogate is supplied: these categorical codec/effect observations have no justified lossy metric. Future caps are 1/2/5/10% only after defining metric, zero behavior and differential reference.

catalog

Source-bound typed models

Each section is a partial source-derived relation on the bound snapshot and declared domain; finite checks are falsification evidence, not a universal proof. Observation horizon is one call unless history is explicitly named.

behavior_complement

No Meta contribution to lbits/total_bits; no division at n=0; absent cbits is zero.

Domain and held state: Finite residual f64 and representable integer counts; volume exact_ok<=volumes for report subtraction. Private helper tests supply synthetic data; model, corpus and report-write CLI paths not executed.