Spec#, nullables and more

[bearophile]

Gary Whatmore:

> I'm seeing it. The other arguments for non-null types also fall short because non-nulls don't solve basic problems like arrays, basic collections in the library (custom fill policy).

Arrays and collections are a subset of the nonull problem I am discussing about. I have shown how Spec# solves this problem. D may choose other solutions.


> Has any mainstream language adopted non-null types?

Ada has them:
http://en.wikibooks.org/wiki/Ada_Programming/Types/access#Null_exclusions

Most functional languages are based on nonullables.

The GNU version of C has a limited form of them:
http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html#index-g_t_0040code_007bnonnull_007d-function-attribute-2458

The problem is faced by Eiffel too:
http://docs.eiffel.com/book/papers/void-safety-how-eiffel-removes-null-pointer-dereferencing


> No they haven't because the idea is broken.

I don't think so.

Bye,
bearophile