C# interview

[Michel Fortin]

On 2008-10-06 09:11:41 -0400, "Denis Koroskin" <2korden at gmail.com> said:

> char? <-> Nullable@(char)
> char*? <-> Nullable@(char*)

Ok, I think see your point.

We only got different interpretations. Mine was that only pointers (and 
object reference) could be made null, therfore, only pointers and 
object references could be nullable, but wouldn't be by default.

Your idea is that any type can be made nullable. For pointers and 
object references, this would be represented by null pointers; for 
other types it'd have to be some kind of struct containing that type 
and a boolean null-indicator value. Is this correct?


Although I don't dislike this idea, I think nullable value-types offer 
much less value than nullable pointers and references. For one, making 
value-types nullable isn't a solution for the problem at hand -- null 
pointer errors (access violation, segmentation faults, etc.) -- because 
value-types already don't have this problem. For two, it makes the type 
memory layout bigger instead of simply allowing it to hold the special 
zero value.

That said, I'm not against nullable value-types. My opinion is that 
perhaps the language could be kept simpler by only allowing pointer and 
object references to be nullable, because that's where it matters the 
most.

-- 
Michel Fortin
michel.fortin at michelf.com
http://michelf.com/