Struct App 

pub struct App { /* private fields */ }

Runnable ECS host pairing one World with one compiled Schedule.

Implementations

impl App

pub fn builder() -> AppBuilder

Starts checked construction with a standard schedule template.

pub fn from_parts(world: World, schedule: Schedule) -> Result<Self, BuildError>

Assembles an application from an already-built world and schedule.

Rejects pending commands, active run guards, poisoned mutation state, and lease mismatch.

pub fn world(&self) -> &World

Read-only access to the owned world.

pub fn world_mut(&mut self) -> &mut World

Mutable world access between passes when the app is not faulted.

pub fn schedule(&self) -> &Schedule

Read-only access to the compiled schedule graph.

pub fn is_faulted(&self) -> bool

Whether a terminal fault prevents further execution.

pub fn fault(&self) -> Option<&AppFault>

Returns the first terminal fault retained by this application.

pub fn set_system_enabled( &mut self, id: &SystemId, enabled: bool, ) -> Result<(), ScheduleError>

Enables or disables one compiled system without rebuilding the schedule.

pub fn update(&mut self, delta_seconds: f32) -> Result<(), AppError>

Runs the full Update pass for delta_seconds.

pub fn update_plan( &mut self, delta_seconds: f32, plan: &UpdatePlan, ) -> Result<(), AppError>

Runs a validated subset of Update stages.

Startup still runs once before the first successful planned update. The selected stages retain compiled order, share one world tick, final flush, and Update-frame event cleanup.

pub fn update_with<R>( &mut self, delta_seconds: f32, observe: impl FnOnce(&World) -> R, ) -> Result<R, AppError>

Runs Update and returns a value observed from the world after frame cleanup.

pub fn render(&mut self, delta_seconds: f32) -> Result<(), AppError>

Runs the Render pass for delta_seconds.

pub fn render_with<R>( &mut self, delta_seconds: f32, observe: impl FnOnce(&World) -> R, ) -> Result<R, AppError>

Runs Render and returns a value observed from the world after frame cleanup.