Re: [PATCH 3/4] vbscript: Implemented Sgn(try 2)

[Jacek Caban]

On 06/24/14 15:59, Shuai Meng wrote:
> 2014-06-19 8:30 GMT+08:00 Shuai Meng <[e-mail]
> >:
> 2014-06-17 17:43 GMT+08:00 Jacek Caban <[e-mail]
> <mailto:[e-mail]>>:
>
>     On 06/17/14 07:59, Shuai Meng wrote:
>     > diff --git a/dlls/vbscript/global.c b/dlls/vbscript/global.c
>     > index c2b2edd..d21784d 100644
>     > --- a/dlls/vbscript/global.c
>     > +++ b/dlls/vbscript/global.c
>     > @@ -1320,8 +1320,24 @@ static HRESULT Global_Int(vbdisp_t
>     *This, VARIANT *arg, unsigned args_cnt, VARIA
>     >
>     >  static HRESULT Global_Sgn(vbdisp_t *This, VARIANT *arg,
>     unsigned args_cnt, VARIANT *res)
>     >  {
>     > -    FIXME("\n");
>     > -    return E_NOTIMPL;
>     > +    VARIANT v;
>     > +    HRESULT hres;
>     > +
>     > +    TRACE("(%s)\n", debugstr_variant(arg));
>     > +
>     > +    assert(args_cnt == 1);
>     > +
>     > +    V_VT(&v) = VT_EMPTY;
>     > +    hres = VariantChangeType(&v, arg, VARIANT_LOCALBOOL,
>     VT_R8);
>     > +        if (FAILED(hres))
>     > +            return S_OK;
>
>     Please use to_double() instead. to_double may need some fixes
>     (it may
>     require similar changes as you did for to_string first).
>
> Yes, to_double is better and simpler. 
>
>     Jacek
>
>
>
> I have tried to_double, but I don't think it is as convenient as
> VariantChangeType.

Not if you fix to_double first. Just call VariantChangeType inside
to_double, like you did in to_string:
http://source.winehq.org/git/wine.git/commitdiff/6bef4da592c8be4857dc0fa179a...
> I have to add more types such as VT_CY and VT_EMPTY, and they don't
> work. For example, if 
>  185     switch(V_VT(v)) {
>  186     case VT_EMPTY:
>  187         *ret = VT_EMPTY(v);
>
> but there is no VT_EMPTY(), how can I give ret whose type is double a
> "EMPTY" value?

Well... of course there is no. As the name suggests, the type "empty" is
empty and has no values ;) What will be result of converting empty to
double is a matter of language semantic and vbscript happens to have the
same semantic as VT_EMPTY->VT_R8 conversion in VariantChangeType.
> Why must we pick up to_double and give up VariantChangeType?

I'm not saying about giving up VariantChangeType, I just want to use it
right.

Jacek