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From: rvn@forth.mlb.semi.harris.com (Rick VanNorman)
Newsgroups: comp.lang.forth
Subject: Re: would it still be Forth? (A thought experiment)
Message-ID: <1990Sep26.172902.13630@mlb.semi.harris.com>
Date: 26 Sep 90 17:29:02 GMT
References: <1990Sep26.084456.8790@idacom.uucp>
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Organization: Harris Semiconductor, Melbourne FL
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in <1990Sep26.084456.8790@idacom.uucp>, rob@idacom.uucp (Rob Chapman) writes:

> I've been toying with the idea of doing this with DOS and botForth on the
> PC.  The input stream is interpreted by looking up parsed strings in the
> dictionary.  If it doesn't exist, try to convert it to a number.  Failing
> this, pass the rest of the input stream on to DOS to be processed as a DOS
> command.  The prompt could even be C:>.  As a matter of fact, if you only
> typed in DOS commands, you wouldn't realize that there was a Forth running!
> (When was the last you checked your command line?)

I tried this for about 2 days last winter (in Florida? ya gotta be kidding!)
and decided that it was not going to be ok without redefining some of the
Forth vocabulary -- there were too many overlaps into DOS (such as TYPE and
ERASE) to feel comfortable.

I did this by using an extension in the interpreter that, upon failing
number conversion, would try to execute the remainder of the input line 
as a DOS command.  It worked pretty well, but I decided not to use it.

Also, the terminal environment that I use for my target-resident Forth 
for the RTX 2000 series maps some common DOS commands.  So, while I am 
executing on the RTX (using the PC for a "smart" terminal/host) I can 
type "DIR" or "CD \something" or any of the commands that I defined. 
Imagine this interface with full DOS access for anything it doesn't
recognize!!  You get to run a Forth engine at full speed, ignoring the
stupid DOS environment until you need it for something, and that something
would be automatically routed to DOS.

I don't know -- I think I'll keep the DOS commands seperate but equal, and
let Forth complain when a word isn't defined.

Rick VanNorman
Staff Engineer, Software Development
RTX Marketing
Harris Semiconductor
Melbourne, Florida, USA

All opinions expressed by me, real or otherwise, are my own.