Re: Why would anyone want opacity?

[William D Clinger <will@ccs.neu.edu>]

Jeff Dalton wrote:

> In any case, I'm not sure how much this has to do with records.
> If the records are opaque, then no one gets to look inside.
> It's not like an ADT implementation gets to look inside while
> client code doesn't.

I have no idea what he meant by this.

No one has proposed write-only records.  The whole point of
having opaque records is to allow the implementation of an
ADT to look inside instances of that ADT while preventing
client code from doing so.

Or at least I thought that was the whole point.  What other
point could there be?

Will