Re: Structures thought question

["Havoc Pennington" <hp pobox com>]

Hi,

On Sat, Nov 15, 2008 at 9:51 PM, Robert Collins
<robertc robertcollins net> wrote:
> On Sat, 2008-11-15 at 21:28 -0500, Havoc Pennington wrote:
>>
>> > void gdk_region_union (GdkRegion       *source1,
>> >                       const GdkRegion *source2);
>>
>> I would expect "inout source1" as "this" and "in source2"
>>
>> source1.union(source2);
>
> I would have expected a union operation to be a three parameter:
> result = source1.union(source2);
>
> (like +, - and other operators).
>
> Not really on-topic I know - sorry :)

Right, I mean that's more an issue with the C API than with how we bind it ;-)

gdk_rectangle_union() is done as 3 parameters:

void  gdk_rectangle_union(const GdkRectangle *src1,
                                      const GdkRectangle *src2,
                                      GdkRectangle *dest);

I guess this would come out as:

 dest = src1.union(src2);

If it's "in src1, in src2, out dest"

Though in C the intent is that "dest" is often the same as one of the
sources, so this ends up kind of inconvenient; you'd have to do:

 dest = src1.union(src2);
 src1.set(dest);

Alternatively, if we declared 'dest' to be inout, you could do:

 src1.union(src2, src1);

But, having dest be inout seems kind of bogus, since it isn't (its
initial value is irrelevant).

Havoc