State

state!(init) allocates a hook slot that survives destroy/rebuild cycles. Slots are ordered by call site and namespaced by the current GUI root_name.

fn app() -> impl Into<Widget> {
    let count = factorio_rs_gui::state!(0);
    let label = format!("Count: {}", count.get());
    // ...
}

API

Call	Effect
`state!(init)`	Create / resume a hook with initial `i32`
`state.get()`	Read current value
`state.set(value)`	Write value and rebuild this root
`state.set_silent(value)`	Write value without rebuilding

state! expands to State::use_state. Prefer the macro at the top of app.

Use set_silent for continuous controls (slider drag, live text). A rebuild mid-drag destroys the element under the cursor. Refresh labels / other widgets in the handler (named elements + set_caption / set_value), or call set when a full rebuild is OK.

Rules

Call hooks in a stable order every rebuild (same as React hooks).
Do not put hooks behind conditionals that change between rebuilds.
Captions are not live bindings, use format! and let set rebuild the tree.
Values live in your mod’s storage under keys like frg:{root}:hook_N.

Types today

Hooks are limited to i32 (for now). Store richer data in your own storage keys and keep a counter (or flag) in state! to trigger rebuilds.