Spec#, nullables and more

[bearophile]

Walter:

> I read your first post as arguing that Spec# in general was a language well 
> designed for security - "Spec# looks very well designed and thought out"

>From that tutorial is looks well though-out, in general (but it's not complete yet). I suggest to take a look at how Spec# implements design by contract (ignoring the fact it enforces those contracts statically), because this may give good insights about how to improve D DbC.

Bye,
bearophile