use bevy_utils::all_tuples;
use crate::{
prelude::{Bundle, Trigger},
system::{System, SystemParam, SystemParamFunction, SystemParamItem},
};
use super::IntoSystem;
pub trait ObserverSystem<E: 'static, B: Bundle, Out = ()>:
System<In = Trigger<'static, E, B>, Out = Out> + Send + 'static
{
}
impl<
E: 'static,
B: Bundle,
Out,
T: System<In = Trigger<'static, E, B>, Out = Out> + Send + 'static,
> ObserverSystem<E, B, Out> for T
{
}
pub trait IntoObserverSystem<E: 'static, B: Bundle, M, Out = ()>: Send + 'static {
type System: ObserverSystem<E, B, Out>;
fn into_system(this: Self) -> Self::System;
}
impl<
S: IntoSystem<Trigger<'static, E, B>, Out, M> + Send + 'static,
M,
Out,
E: 'static,
B: Bundle,
> IntoObserverSystem<E, B, M, Out> for S
where
S::System: ObserverSystem<E, B, Out>,
{
type System = <S as IntoSystem<Trigger<'static, E, B>, Out, M>>::System;
fn into_system(this: Self) -> Self::System {
IntoSystem::into_system(this)
}
}
macro_rules! impl_system_function {
($($param: ident),*) => {
#[allow(non_snake_case)]
impl<E: 'static, B: Bundle, Out, Func: Send + Sync + 'static, $($param: SystemParam),*> SystemParamFunction<fn(Trigger<E, B>, $($param,)*)> for Func
where
for <'a> &'a mut Func:
FnMut(Trigger<E, B>, $($param),*) -> Out +
FnMut(Trigger<E, B>, $(SystemParamItem<$param>),*) -> Out, Out: 'static
{
type In = Trigger<'static, E, B>;
type Out = Out;
type Param = ($($param,)*);
#[inline]
fn run(&mut self, input: Trigger<'static, E, B>, param_value: SystemParamItem< ($($param,)*)>) -> Out {
#[allow(clippy::too_many_arguments)]
fn call_inner<E: 'static, B: Bundle, Out, $($param,)*>(
mut f: impl FnMut(Trigger<'static, E, B>, $($param,)*) -> Out,
input: Trigger<'static, E, B>,
$($param: $param,)*
) -> Out{
f(input, $($param,)*)
}
let ($($param,)*) = param_value;
call_inner(self, input, $($param),*)
}
}
}
}
all_tuples!(impl_system_function, 0, 16, F);
#[cfg(test)]
mod tests {
use crate::{
self as bevy_ecs,
event::Event,
observer::Trigger,
system::{In, IntoSystem},
world::World,
};
#[derive(Event)]
struct TriggerEvent;
#[test]
fn test_piped_observer_systems_no_input() {
fn a(_: Trigger<TriggerEvent>) {}
fn b() {}
let mut world = World::new();
world.observe(a.pipe(b));
}
#[test]
fn test_piped_observer_systems_with_inputs() {
fn a(_: Trigger<TriggerEvent>) -> u32 {
3
}
fn b(_: In<u32>) {}
let mut world = World::new();
world.observe(a.pipe(b));
}
}