Re: Ada Generic vs. C++ Templates

["Pat Rogers" <progers@classwide.com>]

"Simon Wright" <simon@pushface.org> wrote in message
news:x7v66gdw82g.fsf@smaug.pushface.org...
> Colin_Paul_Gloster@ACM.org (Colin Paul Gloster) writes:
>
> > Generics are used in The Booch Components (original Ada 83 version and
> > subsequent Ada 95 port). Pre-Ada 95 it was written on page 192 of "The
> > Design and Evolution of C++" [1] by Bjarne Stroustrup:
> > "[..Grady Booch implemented the Ada [83] version of The Booch Components
> > and he and Mike Vilot later implemented the C++ [of the time] version of
> > The Booch Components. The Ada [83] version] is 125,000 [since you
> > probably speak German I point out that 125,000 in English is equal to
one
> > hundred and twentyfive thousand (big); not one hundrend and twentyfive
> > (small)] non-commented source lines compared to the C++ version's 10,000
> > [10000 not 10] lines - inheritance combined with templates can be a very
> > powerful mechanism for organising libraries without loss of performance
> > or clarity", referencing the second edition of "Object-oriented Analysis
> > and Design with Applications" by Grady Booch.
>
> The C++ BCs I was given a copy of when I started maintaining the Ada95
> port have 29_000 non-comment source lines. The Ada95 port has 13_000
> non-comment source lines.

Another point is that the Booch C++ design for the components is very --
repeat very -- different from the Ada design, so comparing sizes is
difficult.  It is not a matter of inheritance.  There is in fact a lot of
replication in the first design that he realized he could avoid, which has
absolutely nothing at all to do with the language chosen.  It is a matter of
the second design benefiting from the first.

Second, there is little inheritance in the C++ version.  It is not the
central design approach, as it would be in say Java or Eiffel.  No one
should conclude that inheritance is the central reason for the difference in
size.

---
Patrick Rogers                       Consulting and Training in:
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