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use std::any::{Any, TypeId};
use std::fmt::Debug;
use std::ops::{Deref, DerefMut};
use seq_macro::seq;
pub trait Component: Any
{
#[doc(hidden)]
fn as_any_mut(&mut self) -> &mut dyn Any;
#[doc(hidden)]
fn as_any(&self) -> &dyn Any;
}
impl<Value: Any> Component for Value
{
fn as_any_mut(&mut self) -> &mut dyn Any
{
self
}
fn as_any(&self) -> &dyn Any
{
self
}
}
impl dyn Component
{
pub fn downcast_mut<Real: 'static>(&mut self) -> Option<&mut Real>
{
self.as_any_mut().downcast_mut()
}
pub fn is<Other: 'static>(&self) -> bool
{
self.as_any().is::<Other>()
}
}
impl Debug for dyn Component
{
fn fmt(&self, formatter: &mut std::fmt::Formatter<'_>) -> std::fmt::Result
{
formatter.debug_struct("Component").finish_non_exhaustive()
}
}
/// A sequence of components.
pub trait Sequence
{
type MutRefs<'component>
where
Self: 'component;
fn into_vec(self) -> Vec<Box<dyn Component>>;
fn type_ids() -> Vec<TypeId>;
fn from_components<'components>(
components: &'components mut [Box<dyn Component>],
) -> Self::MutRefs<'components>;
}
macro_rules! inner {
($c: tt) => {
seq!(I in 0..=$c {
impl<#(Comp~I: Component,)*> Sequence for (#(Comp~I,)*) {
type MutRefs<'component> = (#(&'component mut Comp~I,)*)
where Self: 'component;
fn into_vec(self) -> Vec<Box<dyn Component>> {
Vec::from_iter([#(Box::new(self.I) as Box<dyn Component>,)*])
}
fn type_ids() -> Vec<TypeId> {
vec![
#(
TypeId::of::<Comp~I>(),
)*
]
}
fn from_components<'components>(
components: &'components mut [Box<dyn Component>],
) -> Self::MutRefs<'components>
{
#(
let mut comp_~I = None;
)*
for comp in components.iter_mut() {
#(
if comp.is::<Comp~I>() {
comp_~I = Some(comp);
continue;
}
)*
}
(#(
comp_~I.unwrap().downcast_mut::<Comp~I>().unwrap(),
)*)
}
}
});
};
}
seq!(C in 0..=64 {
inner!(C);
});
/// Holds a component which is local to a single system.
#[derive(Debug)]
pub struct Local<'world, Value>
{
value: &'world mut Value,
}
impl<'world, Value> Local<'world, Value>
{
pub(crate) fn new(value: &'world mut Value) -> Self
{
Self { value }
}
}
impl<'world, Value> Deref for Local<'world, Value>
{
type Target = Value;
fn deref(&self) -> &Self::Target
{
self.value
}
}
impl<'world, Value> DerefMut for Local<'world, Value>
{
fn deref_mut(&mut self) -> &mut Self::Target
{
&mut self.value
}
}
|