System Sets

[WinstonHartnett]

Goal:

run . build $ do
  parallel [sysA, sysB, sysC] -- checked for dependency conflicts automatically
  sysD                        -- run after line above
  (label @"my label" sysF) `after` sysE -- systems can be labelled
  sysG `before` (getLabel @"sysF")     -- using labelled system
  sysH `whenCriteria` myRunConditionSystem -- run criteria
  sysI `withCleanup` cleanUpSystem         -- on exit

[WinstonHartnett]

Foreign Systems

Foreign systems only declare dependencies at runtime and can run outside the normal ECS graph. While running, other unscheduled systems are run opportunistically. For me, they'd be used to bridge Godot and the ECS backend, i.e. a user clicks a button which adds a foreign system to the ECS scheduler at runtime.