Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!crdgw1!sunbelt!eaker
From: eaker@sunbelt.crd.ge.com (Charles E Eaker)
Newsgroups: comp.lang.forth
Subject: Re: Conditionals !
Message-ID: <17743@crdgw1.crd.ge.com>
Date: 20 Mar 91 20:27:33 GMT
References: <2507.UUL1.3#5129@willett.pgh.pa.us>
Sender: news@crdgw1.crd.ge.com
Organization: General Electric Corporate R&D Center
Lines: 45

> >       [ condition [IF] ]
>
>Someone correct me if I'm wrong, but my understanding is that you'd have to
>use
>        [ condition ] [IF]
>
>and that the construct posted by Charles Eaker would actually have dangerous
>side effects, since if the condition is true, ']' is skipped and the system
>remains in interpret state.

Oops! Blush! Duh! I just put a huge dent into my forehead.

However, thinking quickly, I miraculously turn this into an argument
for my

     IF(   )ELSE(   )THEN

naming proposal in which the parentheses clearly indicate the scope of
what is, and what is not, skipped in the input stream. Consequently,
the construction

     [ condition IF( ] T-stuff )ELSE( F-stuff )THEN
     
clearly *looks* wrong because the over-lapping scopes are quite
evident especially when compared to the correct

     [ condition ] IF( T-stuff )ELSE( F-stuff )THEN

If I had recast the example in terms of these names, I would have
seen, literally, the error immediately.

In the original example,

     [ condition [IF] ]

the brackets appear to be "properly" nested in some way. This is
another reason, I think, against the [IF] set of names, and must be
what I *really* had in mind when I said the brackets are mis-leading.
The [IF] word only opens a scope. It does not represent, as the
brackets strongly imply, a fully self-contained, interpreted scope in
the same way that ['] does.

--
Chuck Eaker / P.O. Box 8, K-1 3C12 / Schenectady, NY 12301 USA
eaker@crd.ge.com        eaker@crdgw1.UUCP       (518) 387-5964