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From: Jacob Sparre Andersen <sparre@nbi.dk>
Newsgroups: comp.lang.ada
Subject: Re: Dispatching Example
Date: Tue, 04 Sep 2001 12:55:44 +0200
Organization: Centre for Chaos and Turbulence Studies, Niels Bohr Institute
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Ed:

> with Dispatching_Examples;
> use Dispatching_Examples;
> procedure Dispatching_Examples_Driver is
>     A, B : T1;                    -- simple variables
>     Q, R : T2;                    -- simple variables
>     C    : T1'Class := A;     -- class-wide variable
>     D    : T2'Class := R ;    -- class-wide variable
> begin
>     C := Is_Item ;              -- static resolution?

Since both:

      C := T2'Class (Q);
and
      C := T1'Class (B);

are legal, the compiler can not possibly figure out which
of the two "Is_Item" functions you refer to. If you want
the compiler to do a static resolution, you have to
specify which type the class-wide variable should be
treated as having:

      T1 (C) := Is_Item;

> end Dispatching_Examples_Driver;

Jacob
-- 
"Then, after a second or so, nothing continued to happen."