| Re: Arg_Present [message #9731 is a reply to message #9641] |
Mon, 04 August 1997 00:00  |
J.D. Smith
Messages: 214 Registered: August 1996
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Senior Member |
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J.D. Smith wrote:
>
> I'm just full of complaints this week. This particular one is about
> Arg_Present. It is a lovely addition, and one for which I clamored
> before the release of IDL v5, but it has something left out... it does
> not correctly identify *inherited* keyword passed variables as return
> variables. This may seem like a small detail, but consider this
> scenario: A subclass' GetProperty method calls its superclass' method
> with any extra keywords it receives. The superclass' GetProperty method
> checks if keywords are present as return variables before computing a
> property for return. But this doesn't work... _EXTRA keywords will not
> trigger arg_present, and the whole system is broken.
>
> Just another link in a long chain of gripes.
>
> JD
Well, this is one of those difficulties which goes even deeper... What
is really happening is that, since _EXTRA keywords get passed in a
structure, they are no longer call by reference, and cannot get passed
out as return items at all. As a fix, I dynamically create a structure
for return of variables, and return it along the method chain, adding to
it as necessary as I go.
JD
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