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From: olehjalmar kristensen - Sun Microsystems - Trondheim Norway
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Newsgroups: comp.lang.ada
Subject: Re: Is the Writing on the Wall for Ada?
Date: 08 Sep 2003 16:55:42 +0200
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Date: 2003-09-08T14:55:42+00:00
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>>>>> "EF" == Ed Falis <falis@verizon.net> writes:

    EF> On Sun, 07 Sep 2003 19:01:48 GMT
    EF> "Robert I. Eachus" <rieachus@attbi.com> wrote:

    >> There is a proposal for Ada 200X to add interfaces to Ada.  It has
    >> been extensively worked, and will almost surely be added.
    >> 
    >> Why?  Because intefaces are different from Ada generics and solve
    >> other problems.  In particular adding interfaces to Ada allows derived
    >> types where the type inherits one parent type and adds one or more
    >> interfaces. 
    >> The user must then provide explicitly declared subprograms to match 
    >> any subprograms in the interfaces that are not provided by the parent 
    >> type.  (In the proposal you can inherit from only interfaces as well. 
    >> But directly inheriting from only one interface is not that
    >> interesting a case.)

    EF> To get a feel for the real power of interfaces, check out "Working with
    EF> Objects" by Trygve Reenskaug.  This is a book from the Smalltalk
    EF> community, but the concepts in it are broadly applicable.  In
    EF> Reenskaug's approach, interfaces are similar to the "roles" he
    EF> describes.

    EF> - Ed

The book is now available for download from the authors as a PDF file.