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Date: Wed, 15 May 2013 07:20:23 -0400
From: "Peter C. Chapin" <PChapin@vtc.vsc.edu>
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Subject: Re: Seeking for papers about tagged types vs access to subprograms
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Date: 2013-05-15T07:20:23-04:00
List-Id: <comp.lang.ada>

On Tue, 14 May 2013, Dmitry A. Kazakov wrote:

>   procedure Foo;

This procedure does nothing unless it has side effects. If so, then those 
side effects entail operations on values of a particular type.

> Value is not a programming language term, it belongs to the application
> domain. Value is the meaning attributed to the state of a typed object in
> some context.
>
> E.g.
>
>   Salary : Buckazoid := 1;
>
> Salary is meant to have the value of 1 Buckazoid.

A type is a pair of sets: a set of values and a set of operations defined 
over those values (for example as functions taking items from the first 
set as a parameter). Either set can be empty. In any case "value" is most 
certainly a programming language term. You can't talk about a type without 
talking about the values that inhabit that type (again, could be an empty 
set in certain special cases).

Peter