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From: Matthew Heaney <matthew_heaney@acm.org>
Subject: Re: Ada OO Mechanism
Date: 1999/06/05
Message-ID: <m3909y7bar.fsf@mheaney.ni.net>#1/1
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NNTP-Posting-Date: Sat, 05 Jun 1999 11:21:32 PDT
Newsgroups: comp.lang.ada
Date: 1999-06-05T00:00:00+00:00
List-Id: <comp.lang.ada>

Hyman Rosen <hymie@prolifics.com> writes:

> From a little fooling around with your code above and gnat, and the
> Rationale, it looks like the compiler has to examine the code that
> attempts to initialize a T'Class variable and allocate the maximum
> space for it that that code would require.

No.  The compiler has no way of knowing at compile-time how much space
to allocate on the stack for the return value of the function.  The size
is determined at run-time.

This is how factory methods work:

  procedure Print (Q : in Queue'Class) is 

    Iter : Iterator'Class := Get_Iter (Q);  
    --
    -- Iter goes on the stack (not the heap), and its size is 
    -- determined at run-time.

  begin