composed top-level constant

ComposedFunctor const composed

Top-level architectural functor providing surgical inline reactive widget composition.

Bridges Flutter's element tree with Bloom's 2-Phase LPDAG engine via an internal ComponentElement mixing in _ReactiveTerminalElementMixin<RawComputedTerminal<Widget>> and _ViaTerminalElementMixin. Evaluates reactive builder closures with an injected BloomVia tracker, updating only the exact composed element upon upstream state mutations without rebuilding the surrounding widget tree.

Unified 12-Entrypoint Hierarchy (4 Modes × 3 Child Axes)

composed               ((context, via) => ...)
 ├── .child            ((context, via, child) => ..., child: W)
 ├── .children         ((context, via, children) => ..., children: [...])
 │
 ├── .vsync            ((context, via, vsync) => ...)
 │    ├── .child       ((context, via, vsync, child) => ..., child: W)
 │    └── .children    ((context, via, vsync, children) => ..., children: [...])
 │
 ├── .animate          (controller, (context, via, controller) => ...)
 │    ├── .child       (controller, (context, via, controller, child) => ..., child: W)
 │    └── .children    (controller, (context, via, controller, children) => ..., children: [...])
 │
 └── .drive            (onTick, (context, via, value) => ...)
      ├── .child       (onTick, (context, via, value, child) => ..., child: W)
      └── .children    (onTick, (context, via, value, children) => ..., children: [...])

System Architectural Flow

[ Upstream Bloom<T> Mutates ]
             │
             │ (Phase 1: 0-Compute Push-Dirty Invalidation)
             ▼
[ RawComputedTerminal<Widget>.onInvalidated: markNeedsBuild() ]
             │
             │ (Flutter Render Pipeline Scheduling)
             ▼
[ _ComposedElement.build() -> terminal.data ]
             │
             ├─► If Clean: Returns cached Widget in O(1) (0-Compute)
             └─► If Dirty: Evaluates user builder(context, via)

Key Invariants & Architectural Benefits

1. Surgical Rebuild Boundary: Rebuilds only the exact composed element without invalidating surrounding parent or sibling widget subtrees.
2. 0-Compute Memoization: Inherits RawComputedTerminal cached evaluation, returning the prior widget instance in $O(1)$ when dependencies remain clean.
3. 1-Pass Zero-Allocation Epoch Diffing: Discards unused dependency branches dynamically in conditional structures without intermediate heap allocation.
4. Subtree Memoization Isolation: Supports .child and .children caching to preserve expensive static subtrees across reactive rebuilds and 60/120fps animation ticks.

See ComposedFunctor.call for primary invocation contracts, parameters, and anti-pattern guidelines. See ComposedFunctor.child and ComposedFunctor.children for static subtree memoization. See ComposedVsyncFunctor for element-level TickerProvider provisioning. See ComposedAnimateFunctor for durable animation controller binding. See ComposedDriveFunctor for continuous frame-ticker drivers.

Examples

final count = blooming(0);

Widget build(BuildContext context) {
  return Column(
    children: [
      const Text('Static Header'),
      composed((context, via) => Text('Count: ${via(count.bloom)}')),
    ],
  );
}

Implementation

const composed = ComposedFunctor._();