On Sunday, 7 June 2015 at 15:39:17 UTC, Marc Schütz wrote:
On Sunday, 7 June 2015 at 15:17:27 UTC, 1967 wrote:
I've got a template that takes in a type. Sometimes the type
is a class, sometimes a struct, sometimes just an int. It
doesn't much matter what it is, but if it's a reference type I
need to check if it's null so I can make it not null before
using it. I get an error if I try to check if a value type is
null so I'd like to put a "static if" to check if the type
passed to the template is a nullable one so I can avoid
checking the value types passed in. What do I have to do to
check for nullability?
You can directly check whether it allows comparison with null:
static if(is(typeof(value is null) : bool)) {
if(value is null)
...
}
Don't forget [`Nullable`][0] type, which won't pass this check.
[0]: http://dlang.org/phobos/std_typecons.html#.Nullable
