Re: [Vala] Arrays in generics

[Luca Bruno <lethalman88 gmail com>]

On 05/03/2014 20:36, James Dean Palmer wrote:
> Hi, I'm new to Vala and have run into an issue with generics and arrays.
>   Consider this example:
>
> public class Vector<T> {
>      internal T[] items;
>      ....
>      public Vector.from(T[] source) {
>      ....
>      }
> }
>
> This allows me to conveniently initialize the vector like this:
>
> new Vector<string>.from({"Fred", "Daphne", "Velma"})
>
> But the problem arises that if I do the same thing with integers:
>
> new Vector<int>.from({1, 2, 3})
>
> Vala doesn't complain but the c compiler does because the generic is
> representing the array as a gpointer* where outside the generic the array
> is gint*.  Since the size of the types is different I can't correctly
> access an integer array from within a generic nor can I correctly pass a
> gpointer* back to a gint*.  So while it compiles, the results are wrong
> because when I use the array it is moving across the array at the wrong
> stride.  To illustrate my point, this works correctly because the size is
> compatible on my system:
>
> new Vector<long>.from({1l, 2l, 3l})
>
> Is there anything I can do to check the type or size of T in the generic to
> provide custom type/size specific initialization?  Or is there some other
> technique I might employ other than creating non-generic containers
> (IntVector, BoolVector, etc..)?
You can check the type like typeof(T) == typeof(int)