template<typename... Ts>
except struct
tag that disallows a certain component to be present on the given entity.
Sometimes you want to filter on all items, except a subgroup. This tag can aid in this. For example, if you had a debug system that would log an error for all entities that are renderable, but lacked a transform, then you could use the except tag to denote the filter what to do as a hint. Except directives are always executed last, regardless of order in the parameter pack.