Impl `HandlerParam` for `&World`, `&mut World`

rj00a / evenio

An event-driven Entity Component System

MIT License

132 stars 14 forks source link

Impl `HandlerParam` for `&World`, `&mut World` #60

Open andrewgazelka opened 4 months ago

andrewgazelka commented 4 months ago

Pros

This is possible to do in Bevy.
It might be nice given #57 improvements and until #44 is implemented, which would allow non-static events when we do not have access

Cons

I am not sure how much this would be used. Right now, I have everything that would need a &World or &mut World running outside of a system.

rj00a commented 4 months ago

&World might be doable, but &mut World within a handler would lead to unsoundness. It would be possible to send an event for the currently running handler, causing mutable aliasing. You could also do things like remove handlers which would invalidate the iterator over the current HandlerList.