From: lanmaint@nssdca.gsfc.nasa.gov (Dave Yoest)
Subject: Re: FORTH-83 for Atari 8-bit; anyone interested?
News-Software: VAX/VMS VNEWS 1.41    
Organization: NASA - Goddard Space Flight Center
Date: Thu, 31 Dec 1992 12:58:00 GMT

In article <1992Dec30.035608.22678@mtu.edu>, jjmcwill@mtu.edu (Jeff McWilliams) writes...
>Pardon my ignorance toward Forth folks, but what was the language designed
>for, and what are the PROS and CONS for choosing FORTH over some other
>programming language?
> 
>Jeff McWilliams
> 


I haven't used Forth for many years, and this is an "off the top of my 
head" answer, so I may be wrong. 

As I recall, Forth was developed in the 70's by an astronomer. The 
name Brodie keeps coming to mind, but that could be a book author.(I'll 
look up the name if anyone really wants to know) From what I 
understand, it was a SW tool he wrote to control the positioning of 
large telescopes, and later got some use in the robotics disciplines.
It was very "bare bones", and you were supposed to write your own 
routines for almost everything. In fact, every routine (called a 
word in forth) became an extension of the language.

It was the main language I used on my 400/800's, I got the 800 back in 
1982, and since I was never real fond of basic I got the VALforth
development kit. I heard rumors that VALForth was used internally by 
atari as a game development language. Later A PD Forth calle FIG-Forth
was released and its core was as good as the Valpar Forth, but didn't
have all the neat pre-packaged routines for things like PM 
graphics, strings ,trig,  and the like, so you had to write 
your own. I kind of liked it because  Forth is an interpreted language
rather than compiled, so I could try out ideas without the 
edit-assemble-debug-edit-assemble-debug cycles that were time 
consuming with MAC65. (Remember, this is the early 80's before 
Action!)

Then I switched to C , and did no SW development on my atari for the
last 5 years. Recently I started writing some small programs again (for
my kids), but I'm using LOGO instead of Forth. I just can't deal with 
adjusting to Reverse Polish notation again. 

Atari Logo is a very good implementation of LOGO, and I have free 
versions of Xwindows Logo on my unix machine and there's a really 
amazing free logo for MSwindows. Code portability from atari to 
X-LOGO or MSWinLogo is very good. If you want to write simple programs
or teach your kids about computers, I highly recommend Logo.

Forth Pros:

  Its portable to other machines. Of course, you have to write good 
  code in the first place if you want it to port easily. I ported most 
  my stuff to the PC without a lot of work when I started using it as my 
  work machine and made the ataris strictly fun machines.

  It's interpreted rather than compiled, so you get instant results.

Forth Cons:

  The biggest con was the reverse polish notation. I got used to it, 
  but it wasn't natural. In my opinion, the expression 2 2 + . is not 
  clear as " add 2 and 2 and print the result. Doing anything in basic
  then became a problem, because the command "20 LIST" in forth will 
  list screen 20, and you get used to it working that way. Then you do 
  something in basic, and want to see line 20, so you type "20 LIST" by 
  habit. Then you get to remember what line 20 was supposed to be, 
  and retype it. 

  It's not as fast as Assembeler, and not that much easier to use than  
  a good macro assembeler (once you get a few usefull macros in your 
  library) For serious Atari 8-bit development, I think Action is 
  probably a better choice, unless you plan to port to other machines
  that support Forth.




Dave Yoest
LAN Ops & Engineering Section Supervisor
NASA/Goddard Space Flight Center
Greenbelt, Md. USA  20646

(301) 286-7033

DYOEST@ZAPHOD.GSFC.NASA.GOV 



Newsgroups: comp.sys.atari.8bit