[Vala] Array parameter calling conventions

[Walter Mundt <emage spamcop net>]

I've noticed that in VAPI files, there seems to only be two calling
conventions for array-type parameters: with and without the length and
size params passed.

To make it cleaner to bind to C libraries, it would be nice to have a
more flexible way to specify this.  How hard/desirable would it be to
add a CCode spec that operates vaguely like this:

Base function, and call in Vala:
  public static void foo(int[] bar);
  int[] mybar;
  foo(mybar);

Variant A:
  public static void foo([CCode(array_params="length,ptr")]int[] bar);
generates:
  foo(mybar_length, mybar);

Variant B:
  public static void foo([CCode(array_params="ptr,size")]int[] bar);
generates:
  foo(mybar, mybar_size); // some C API's want a byte count
                          // rather than an element count


This would allow you to write a VAPI file that seamlessly passes
whatever array length/size information is desired in whatever order the
pre-existing C declaration wants it, as long as the size parameter is in
some way adjacent to the actual array pointer.

--
Walter Mundt
emage spamcop net