Looks like the delegate / data source pattern [1] which is prevalent in Cocoa programming.

[1] https://developer.apple.com/library/archive/documentation/Ge...

Congratulations to Martin Fowler on inventing reader monads with context objects!

Lets hope next time it doesn't take him 2 decades of ignoring Haskell inventions to actually find out if it is a good invention!

/s in case it's not obvious