Re: SWOOP vs. SwiftX

Yes, there is some overhead for delayed binding (virtual functions). There
is a lookup time for an address, and there is the need for a place to put
the address. "A fair amount" is a relative term. Encapsulation and
inheritance overhead is mostly compile-time, and don't have a large impact
on the target code (at least, not in C++, and I would not expect a runtime
penalty in Forth). Some of what I'm after could be accomplished by use of
vocabularies, but it appears that vocabularies have changed a bit since my
PolyForth days, and it isn't clear to me (yet) how they work wrt SwiftX (I
hope to get over that soon...).

The application with which I am currently working is larger than the typical
embedded system, and because of the lack of something like SWOOP, a
predecessor (a frustrated C++ programmer who is no longer with the company)
implemented a heavyweight and much less elegant partial OOP solution with
which I am now stuck. I would be happy with just some namespace control
(object-based in lieu of object-oriented, i.e., leaving out the
polymorphism); the number of words in the system is so large that I am using
hypenated group prefixes to keep them straight; a very un-Forth-like
approach.

Howard Lee Harkness, Contractor

-----Original Message-----
From: swiftx-bounce_at_forth.com [mailto:swiftx-bounce_at_forth.com] On Behalf Of
Elizabeth D Rather
Sent: Monday, July 11, 2005 12:34 PM
To: swiftx_at_forth.com
Subject: [swiftx] Re: SWOOP vs. SwiftX

We have not implemented SWOOP in SwiftX at all at this time, mainly due to
lack of demand. The CLASS word you're seeing is the one in SwiftForth, and
will not support anything in a SwiftX target.

There's a fair amount of overhead involved in any OOP scheme, and most
embedded applications need to find more efficient ways of doing what they
need to do.

Cheers,
Elizabeth

============================================
Elizabeth D. Rather
FORTH Inc. +1 310-491-3356
5155 W. Rosecrans Ave. Fax: +1 310-978-9454
Suite 1018 (US & Canada) 800-55-FORTH
Hawthorne, CA 90250
http://www.forth.com

"Forth-based products and Services for real-time applications since 1973."
============================================

> -----Original Message-----
> From: swiftx-bounce_at_forth.com [mailto:swiftx-bounce_at_forth.com]On
> Behalf Of Harkness, Howard
> Sent: Monday, July 11, 2005 7:50 AM
> To: 'swiftx_at_forth.com'
> Subject: [swiftx] SWOOP vs. SwiftX
>
>
> I am relatively new to SwiftX, and I am a bit puzzled wrt SWOOP. I
> have a pretty thorough understanding of OO (I have taught OOA&D
> courses), so I was looking at SWOOP with the idea of using objects and
> polymorphism in an embedded application. However, I note that the
> CLASS word is available only in HOST. Does that mean that SWOOP is
> only intended for host defining words, and not for use on the target?
> If there is any documentation or example available for the use of
> SWOOP on a SwiftX embedded target system, I would like to see it.
>
> Howard Lee Harkness, Contractor

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Received on Tue Jul 12 2005 - 07:36:45 PDT