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From: dwpst@unix.cis.pitt.edu (Douglas W Philips)
Newsgroups: comp.lang.forth
Subject: Re: What makes Forth Forth
Summary: necessary vs. sufficient
Message-ID: <68713@unix.cis.pitt.edu>
Date: 7 Dec 90 22:52:09 GMT
References: <9012051459.AA18739@ucbvax.Berkeley.EDU> <12692@medusa.cs.purdue.edu> <14789@sdcc6.ucsd.edu>
Reply-To: dwpst@unix.cis.pitt.edu (Douglas W Philips)
Organization: Univ. of Pittsburgh, Computing & Information Services
Lines: 59

In article <14789@sdcc6.ucsd.edu> ir230@sdcc6.ucsd.edu (john wavrik) writes:
>The fact is that for quick development and debugging, an interactive 
>environment is desirable. That other languages also offer this does 
>not negate the fact that Forth does too -- and that it is an asset. 
>'C' does not have this feature (nor does Pascal, FORTRAN, Modula2, 
>Ada, etc.) 

I got lost here.  To what does your last "it" refer?  Certainly not
to interactive environments for C/Pascal, etc.  Those exist.

>While on this subject, "factoring" is a programming technique not a 
>Forth feature.
...
>The idea that Forth programmers use (and have used) a technique which 
>is now recognized as "good style" speaks well for Forth and Forth 
>programming techniques --- but is not what makes Forth Forth.

Agreed.  

>2.  To make sure that essential properties of the language are not 
>    lost in the process of "popularizing" it or "making it 
>    marketable". 

Agreed.  Of course, you have to know what those essential properties are
in order to be able to protect them.

>                               I *DO* see an objection -- and I 
>regard a strength of Forth as the ability to add new objects with 
>first class status. This ability comes from the fact that the Forth 
>programmer has access to the language at the level at which primary 
>objects are introduced...

Well, what do you say to the C++/Ada/Smalltalk people then.  They can
certainly do that too.

>P.S.  The main challenge to the Forth community is to show that 
>      putting more control over the language in the hands of the 
>      programmer can result in more power without drastically 
>      increasing error or increasing the incidence of incompre-
>      hensible programs. 

I have seen nothing so far that would enable me to distinguish PostScript
from Forth.  In fact, the power and popularity of PostScript would seem
to have proved the point already.

			Forth @ 1+ PostScript !

As we have already seen, it is easy to sketch in where Forth is
different from the profane edit-compile-debug languages.  I think that
trying to find the line between Forth and PostScript and Fifth and ...
will necessitate a deeper inquiry into and understanding of the issues
involved.  (I could be wrong, the last time I brought up this question
the answer eventually was:  They're different because they are.)  Even
CM's own characterization of the essentials of Forth would apply to
PostScript and Fifth.  (I seem to recall them from a transcript of
talk/speech CM gave that was reprinted in Volume one of FD, if I can
find it I'll extract more details).

-Doug