Invariants for methods

[bearophile]

Jens Mueller:

>This copying behind the scenes seems surprising to me. Maybe I do not fully understand the
approach.<

The compiler statically knows what things are needed in their older state (only ones accessed with "old." in the postcondition), so useless copying is avoided.


>that right now there are more important problems.<

There are always more important problems. The most important one is probably that DMD development process doesn't taste Open Source enough yet (but the situation is improving: Phobos is slowly becoming more and more like an Open Source project, despite being not there yet).


>I mean I do not know when people started complaining about Java missing proper DbC but I'll guess it was a lot later.<

This is probably right.


>If it starts itching then scratch it.<

I see, you like "just in time design", D is usually designed like that :-)
I guess your problem was one of the best itches you will see on this.


>I hope there is no inherent design problem.<

This time I think there is no inherent design problem, it's just a missing feature that may be added later.


>I think this problem does not prevent D's success. I might be wrong here but nobody is not switching to D because this does not work.<

Who knows, maybe a Eiffel programmer will refuse to use D because this feature is missing :-)


>It's more the bugs/API changes/tools that keep people away. At least that's my impression. It does not seem mature enough for some people.<

But I'd like a good language to build on. In the end Walter, Andrei and Don know way better than me.

Bye,
bearophile