2011/9/2 Conor McBride
<conor@strictlypositive.org>
Also, if I understand you correctly, you say the current situation is
exceptional, and suggest option 2 as a temporary solution to it. You
seem convinced that these kind of situations will not appear in the
future, but I'm not as optimistic about that.
Even when superclass defaults are implemented, people will
occasionally implement classes without realizing that there is a
suitable intrinsic superclass (or add the superclass but not the
default instance). People will start using the new class and give
separate instances for the superclass, and eventually someone will
point out that the there should be a default instance for the
superclass. Now if option 1 is implemented, the library maintainers
will be reluctant to add the superclass instance because it will break
a lot of client code.
no choice but to do things badly, but things often get done badly the
first time around anyway. Perhaps I'm just grumpy, but I think we
should aim to make bad practice erroneous where practicable. Once
the mistake is no longer forced upon us, it becomes a mistake that
deserves its penalty in labour. Silent pre-emption is bad practice and
So, when the whole point is that an unfortunate design years ago can't be reasonably fixed without rewriting massive amounts of code, the only correct answer is to rewrite massive amounts of code? Especially when the original proposal was put forward *specifically to avoid* rewriting massive amounts of code?
Yes, we'd love a perfect world. We don't have one. That's the *point*.