Re: [Vala] Static array initialization

["Cayle Graumann" <cayle graumann gmail com>]

Speaking of array initialization - I came across an oddity the other
day in version 0.0.6 in that the following syntax would not compile.
I have not tried it with 0.0.7 yet as I am still trying to change over
my code to the new constructor syntax to test other things yet.

function x (int buffersize) {

     int[] i;
     if(buffersize>10) {
            i = new int[100];
     } else {
            i = new int[10];
     }

}

The vala compiler complained about the "int[] i" not being valid.

I eventually was able to work around it by doing this which is of
questionable efficiency:

function x(int buffersize) {
       var i = new int[1];
       if(buffersize>10) {
             i.resize(100);
       } else {
             i.resize(10);
       }
}

I would assume that my first try should evaluate to something like this

  int *i;
  if(buffersize>10) {
           i = ourmalloc(100*sizeof(int));
  } else {
           i = ourmalloc(10*sizeof(int));
  }

where ourmalloc is whatever function we are using to allocate memory.

Is there another way of doing this that I am just missing, or is this a bug?

I like the fact that we can now resize arrays, but wonder at how
efficient an implementation it is.  I have some code I'm porting that
extensively uses a linked list (C# ArrayList) of integer arrays to
allow efficient array growth, and if the new resizable arrays are good
enough then I might not worry about reworking that code.

Cayle, Missouri.

On 3/8/07, Dominique Würtz <housirer gmx de> wrote:
> First of all, thank you for your help, your code works for me and
> declaring the array as const is certainly more appropriate here.
>
> However, I'd like to point out that C allows initialization of arrays of
> any type, f.e.
>
> int main (int argc, char ** argv)
> {
>   struct {
>     int a;
>     char *b;
>   } x[] = {
>     { 1, "111" },
>     { 2, "222" }
>   };
>
>   return 0;
> }
>
> runs perfectly, and you can declare x[] as static, const or whatever.
> Thinking about it, what reason is there to not allow initialization of
> non-const arrays?
>
> Cheers,
> Dominique
>
> Raffaele Sandrini schrieb:
> > Ok this one is tricky ;). The point is that the programm above is
> > incorrect. You are not allowed to create non const arrays of structs.
> > This is also not allowed in C. Nevertheless valac does not complain
> > about that (as of many other things) ;).
> >
> > The correct array initialisation would be:
> >         const Gtk.ActionEntry[] entries = {
> >                 { "FileMenu", null, "_File", null, null, null },
> >                 { "EditMenu", null, "_Edit", null, null, null },
> >               null
> >         };
> >
> > have fun
> > Raffaele
> >
>
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