Path: utzoo!attcan!uunet!jarthur!usc!wuarchive!psuvax1!psuvm!dn5
From: DN5@psuvm.psu.edu
Newsgroups: comp.lang.forth
Subject: Re: ... and zen there were objects.
Message-ID: <90227.092721DN5@psuvm.psu.edu>
Date: 15 Aug 90 13:27:21 GMT
References: <1990Aug7.081509.2315@idacom.uucp>
 <1498.UUL1.3#5129@willett.pgh.pa.us>
Organization: Penn State University
Lines: 42

In article <1498.UUL1.3#5129@willett.pgh.pa.us>, dwp@willett.pgh.pa.us (Doug
>What I think is wrong with Object Oriented Extensions to Forth:

  [Deleted text]

>That looks ok, but it does not do anything.  In order to do something you
>would have to add a special word.  I would pick SEND, as in:
>        10 20 MoveTo MyRectangle SEND
>
>the nice thing about having an explicit send is that you can replace
>MoveTo and/or MyRectangle with arbitrary Forth code and still have it
>work.

My comments:

I don't like this syntax, because it means that I would have to
do something special if I had a function which returned an object
(i.e., I had an anonymous object on the top of the stack).  The
syntax which I came up with when I was experimenting with objects
in forth is similar:

    10 20 MyRectangle ~ MoveTo

Using the Mac keyboard, I had access to all sorts of funky symbols,
but I liked the tilda best, because it is obvious, unused, and also
on most other keyboards of other systems.

Basically ~ was an immediate word which took the next word as a
string, and hashed it to a method reference, and compiled a call
to the object dereferencer with that as a parameter.  In the future
I would replace all calls which could be figured out at compile
time to a direct call to word involved.

Unfortunately, I never got any further than creating the syntax,
because somebody offered me actual cash to work on something else.
Hopefully in the fall I can go back to work on this, so I can have
a better development environment than Pascal or C. :-)  :-)

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D. Jay Newman                !  All syllogisms have three parts,
dn5@psuvm.psu.edu            !  therefore this is not a syllogism.
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