roundtrip-main

The groupant beside tools/roundtrip/src/main.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	`model.md`
ast	partial	`syntax.json`
composition	partial	Composition
cost	partial	invariant-and-cost
descriptant	present	descriptant
invariant	partial	invariant-and-cost
tests	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
`spec_precedence`	spec_precedence	partial source derived model	spec_precedence
`worker_order`	worker_order	partial source derived model	worker_order
`option_default`	option_default	partial source derived model	option_default
`write_prefix`	write_prefix	partial source derived model	write_prefix

Parts

Model text

descriptant

roundtrip-main

2026-10-31 prospective epoch retained externally before edits.

Parses command and options; mixed/blocks/site-learn delegate early. volumes splits kind colon, final @ stride and then dispatches readers. run creates out directory before model load, processes sets and sequentially writes report/examples/residual/normal. run_set schedules atomic indices and merges stored results in input order.

No annotator/model loading, live corpus, full suite, teacher, GPU or persistent-learning evidence. No executable percentage surrogate: categorical codecs/effects need a useful metric before future caps 1/2/5/10%.

Exact recovery with residual is a diagnostic codec observation. It is not evidence of normal generative equivalence, semantic understanding or persistent learning. Production source is preserved; only isolated tests are appended where needed.

approximant

Forward relation

Domain: bounded synthetic values, valid source-specific coordinates, nonoverflowing counts, available allocation; fixed environment controls. Relations are source-derived partial models with finite checks, not universal proofs.

Composition

Source children delimit real function scopes, sharing syntax. Real pipeline joins R4 frame reconstruction to Realizer then R3 tree script and R2 token decode; report consumes aggregated tally. Independent path/CLI branches are not fictitious codec callers.

catalog

behavior_complement

Subject: roundtrip-main, source hash 00f4bbcd3c873394f1a661e52a0dc3360dc8f4f368d9f33113d3f6c6ac2e4109; transition observation.

An invalid stride prevents unknown-kind dispatch and all volume readers. Successful model load does not imply later writes all succeed; no rollback protects already written reports. No actual CLI load/run is executed here.

Evidence: external wave32 rt_core receipt includes native-commands.json, exact named outcomes twice debug/twice release, raw status/log files, compiled production controls with byte restoration and paired syntax. Only named synthetic helpers execute; model_path/export and live CLI paths have representation/source evidence.