> You seem to trust that programmers will play by the rules, even if the compiler doesn't enforce them.
I've been trying to say the exact oppisite. C, C++, Javascript, all those languages provide ways to define abstract datatypes that cannot be circumvented (by "normal" code. Even Haskell has unsafePerformeIO). My latest argument was that people decide not to use those abstractions not because they are unavailable, but because it is more ergonomical or performant not to. The same happens even in ML, not all data is abstracted as an abstract data type.
I've been trying to say the exact oppisite. C, C++, Javascript, all those languages provide ways to define abstract datatypes that cannot be circumvented (by "normal" code. Even Haskell has unsafePerformeIO). My latest argument was that people decide not to use those abstractions not because they are unavailable, but because it is more ergonomical or performant not to. The same happens even in ML, not all data is abstracted as an abstract data type.