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From: dwp@willett.pgh.pa.us (Doug Philips)
Newsgroups: comp.lang.forth
Subject: What makes Forth Forth
Message-ID: <2096.UUL1.3#5129@willett.pgh.pa.us>
Date: 12 Dec 90 16:29:42 GMT
Organization: String, Scotch tape, and Paperclips.  (in Pgh, PA)
Lines: 60

In <14813@sdcc6.ucsd.edu>, ir230@sdcc6.ucsd.edu (john wavrik) writes:
> Doug Philips writes:
> # 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. 
> 
> I must be missing something: what point has been proved?
> The popularity of Postscript is not the topic being discussed.

Ok, I was being too obscure.  My point was that I was assuming PostScript
and Forth were similar enough languages that PostScript's success might
be something, fait accompli, that would show (to whomever it is supposed to
be shown) "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 incomprehensible programs."

> I don't want to put words in Moore's mouth -- but I think you will 
> find that Forth was NOT created by developing a theory of what 
> characteristics a language should have, then making the language 
> fit the theory. Moore instead seemed to follow his instincts in 
> making design decisions as the language evolved. The result is 
> that the language assumed an identity of its own that even its 
> creator stands back and studies. Its a bit like the relationship 
> of a parent to a child.  

I never intended to assert that Forth was designed rather than evolved.
On the other hand, your analogy doesn't work.  There is nothing in
Forth that wasn't put there, even if "unconciously."  Because
Forth was evolved you can't analyze it to find out what is "essential
Forth" and what is "accidental Forth"?  There are many languages called
Forth: Forth-79 fig-Forth, Forth-83, etc.  No one seems to dispute that
regardless of differences in the spelling of the words used to make
defining words, differences in dictionary structure (such as PC
"separate segments"), presence or absence of vocabularies of n different
kinds, differences in the inner interpreter (indirect
threaded, direct threaded, native code), there must be something more
fundamental than those things which groups them all as Forth, yet manages
to exclude PostScript.

> trying to identify the factors responsible. There are two serious 
> purposes for wanting this done: 

I assume you aren't limiting the list to just these two items.

> 1.  If a move is made to gain acceptance for the language in an
>     academic arena several things are needed -- among them the 
>     ability to discuss the language in the way that other computer 
>     languages are discussed.

Just think of all that cretinous parsing and lexing theory you can
trash by teaching Forth!  Plus the complicated intermediate compiler
structures.  Even optimizing Forth compilers are easy to do and
extensible (see recent Forth Dimensions).  Compare and contrast with
the direction of Ada/C++ and see whether academia is in love with
complexity (gratuitous or not).  I doubt that the solution to
academically-legimitizing Forth is a simple one.

-Doug
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