Re: How to test object hierarchy

["Robert I. Eachus" <rieachus@comcast.net>]

Robert A Duff wrote:

> Yes, it can be instance.  It can also be a renaming.
...
> I didn't follow the entire discussion, but yes, I think that could work.

Before somebody gets bent all out of shape trying to implement the idea, 
there is a subtle gotcha here that has to be avoided.  It is often 
difficult (but not impossible) to define the generic you want before the 
freezing point.

There are two workarounds, which often occur naturally.  The first is to 
make the signature of the subprogram dispatching.  Then in the body, 
implement the subprogram as a generic instance.  Or you can make the 
generic an operation of a parent type, so that the generic instantiation 
can appear before the freezing point of the child type, but after the 
freezing point of the parent.

As I said, you may naturally not run into a problem.  Depends on how you 
define the generic and other things.  But if you do have a problem, move 
the instantiation to the body of the package that defines the type.

-- 
                                           Robert I. Eachus

"The war on terror is a different kind of war, waged capture by capture, 
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