On 03-08-2012 22:40, bearophile wrote:
Alex Rønne Petersen:
So what if, for whatever reason, the invariant needs to track and
maintain some state in order to catch some kind of ugly bug?
This is legitimate practical need. I know two or more ways to solve that
problem, one of them is to implement the prestate (old). That's probably
the largest hole in the D implementation of contract programming, and I
have felt its need several times.
Another solution (that doesn't replace the need for the prestate!) is
ghost fields, that are class instance/struct fields usable only inside
contracts and that vanish in release mode:
http://d.puremagic.com/issues/show_bug.cgi?id=5027
Bye,
bearophile
I've used prestate in Spec#/Sing# and can definitely vouch for its
usefulness.
--
Alex Rønne Petersen
[email protected]
http://lycus.org
