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From: Matthew Heaney <matthew_heaney@acm.org>
Subject: Re: Help - Constructors - ASAP.
Date: 1998/08/01
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Date: 1998-08-01T00:00:00+00:00
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dewar@merv.cs.nyu.edu (Robert Dewar) writes:

> <<But, a naieve reader would look at that and think that they could
> get back an object of *any* type in the class (as I have just proven
> :-) ), when in actuality they always get back the same class of
> object.
> >>
> 
> That's a pretty fundamental misunderstanding of what classwide
> programming is all about. Yes, of course people can have all sorts of
> misconceptions, but this one is pretty basic, and not a misconception
> that could stay arround very long!

I'm with Robert on this one.  You have to recognize something as an
idiom.  When you see a function

   function New_T return T'Class;

you just have to "know" that this is a constructor for T, and for T
only.  Once you recognize the idiom, you know instantly that

   type NT is new T with private;
...
   O : NT := New_T;

is wrong, even though the compiler won't tell you it's wrong.