Elamur Groupantsworld-build
The groupant beside world/build.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 | partial | Invariant and cost |
| Descriptant | present | Descriptant |
| Invariant | partial | Invariant and cost |
| Tests | bounded or representation | 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.
| relation | type | label | where |
|---|---|---|---|
| Behavior complement | behavior complement | partial source derived model | Behavior complement |
| Reverse reconstruction | reverse reconstruction | partial source derived model | Reverse reconstruction |
Model text
Descriptant
The build script of the world crate. It decides whether the legacy central manuals (state::CENTRAL_MANUALS,
feature worlds, also enabled by peta) are compiled in: only when the feature is on and the folder
peta/world/legacy/worlds exists beside the crate. It exists so that a public checkout, which has no peta/,
compiles with --all-features (2026-11-05).
Approximant
Forward relation: F(feature_worlds, dir_exists) emits rustc-check-cfg=cfg(mova_legacy_worlds) and
rerun-if-changed=build.rs always; then
- feature off: nothing more;
- feature on, folder present:
rerun-if-changed=<folder>andrustc-cfg=mova_legacy_worlds; - feature on, folder absent: one
cargo:warningnaming the absent folder, no cfg.
Composition: cfg(mova_legacy_worlds) selects the include_str! table of state.rs (otherwise the empty table)
and the test nerves::time_words_reach_the_world_of_time. The freesync export treats this cfg as false
(PRIVATE_BUILD_CFGS), since the export has no peta/.
Behavior complement
It never reads the manuals, never checks that the 33 named files exist (a partial folder fails later at
include_str!), never sets the cfg without the feature, and never fails the build. Watching a directory notices
added or removed entries, not edits inside files (cargo's directory rule).
Reverse reconstruction
From the emitted cfg one recovers (feature on ∧ folder present); from its absence only (feature off ∨ folder absent), which the warning disambiguates: a warning means feature on and folder absent. The folder's contents are not recoverable.
Invariant and cost
Invariant: mova_legacy_worlds ⇒ feature worlds ∧ the folder existed when the script ran. Cost: one environment
lookup and one stat; O(1).
Tests
Compiled with and without the folder: cargo check -p world --features peta in the private checkout (manuals in),
and cargo check --all-features on the public export (warning, empty table), 2026-11-05. No unit test: the script's
inputs are cargo's environment and the file system.
Provenance
This page in Markdown → https://md.groupants.elamur.ai/free/en/mova/world/build.rs.groupant/