Nullable types

[bearophile]

Lionello Lunesu:
> Although it sounds like D's NaN initializer: if there's even one NaN 
> somewhere in a big calculation, the result of the calculation will likely be 
> NaN as well. And here it helps finding bugs.
> Now, if only ints and object references had a real NaN equivalent.... :-)

Again, see the Maybe of Haskell:
http://en.wikibooks.org/wiki/Haskell/Hierarchical_libraries/Maybe

Bye,
bearophile