ifc-cost — cost semantics as a view over the model.

This crate owns no data

It borrows a &Model and interprets entities that happen to be cost entities. That is the whole design: the model stores structure, this crate supplies meaning, and the two are separable.

The consequences are the point:

• Optional. An application that never touches cost compiles none of this. It is a cargo feature of the ifc facade crate.
• Non-destructive. Because the model holds the same entities with or without this crate, a file with cost data round-trips identically in either build. Verified in ifc/tests/costing_roundtrip.rs, which runs with no domain crate compiled at all.
• Replaceable. A different interpretation of the same entities is another crate, not a fork of the model.

Modules

use ifc_cost::CostView;
use ifc_model::{Entity, EntityId, Model, Value};

let mut model = Model::new();
model.insert(
    EntityId(1),
    Entity::new("IFCCOSTITEM", vec![
        Value::Text("guid".into()), Value::Null, Value::Text("Excavation".into()),
    ]),
);

let view = CostView::new(&model);
assert_eq!(view.items().next().unwrap().name(), Some("Excavation"));