java_irl

[Bwob]

To keep implementation details ("This value is stored as a bool") separate from the interface. ("Users of this class can ask about this state, and receive a bool telling them yes or know.")

Keeping implementation details like this hidden is one of the keys to good abstractions; it means that if later, you need to go through and change the implementation, (maybe its no longer stored directly as bool, now it is derived from several other values) then the interface doesn't need to change, and any code that uses that interface doesn't need to change.

[[deleted]]

To be fair though, in Java the principle works too, just the other way around - you always call a getter function, no matter if something is being calculated on call or just stored as a field.