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From: "Robert I. Eachus" <rieachus@attbi.com>
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Subject: Re: Is the Writing on the Wall for Ada?
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Date: 2003-09-23T08:19:39+00:00
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Hyman Rosen wrote:

> So, does Ada have an equivalent to this? Remember, you do not
> control IFoo, IBar, the container type, or the implementation
> of the type which is trying to be the combination of an IFoo
> and an IBar.


The equivalent in Ada is:

if Object in IBar'Class then...

More to the point:

if Object in IBar'Class and Object in IFoo'Class then...

may be true.

if Object in IBar and Object in IFoo then...

Will never be true unless IBar is a renaming or subset of IFoo or 
vice-versa.   Every object is a member of exactly one specific (base) 
type, but it may be a member of many classwide types.
-- 
                                         Robert I. Eachus

Ryan gunned down the last of his third white wine and told himself it 
would all be over in a few minutes.  One thing he'd learned from 
Operation Beatrix: This field work wasn't for him. --from Red Rabbit by 
Tom Clancy.