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From: UNBCIC@BRFAPESP.BITNET
Newsgroups: comp.lang.forth
Subject: ANS TC Magnet for Division
Message-ID: <9007292127.AA24336@ucbvax.Berkeley.EDU>
Date: 28 Jul 90 21:47:00 GMT
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From: DCS@CIC.UNB.ANDF.BR
To: FIGI-L@SCFVM.BITNET
Subj: ANS TC Magnet for Division


      I think ANS TC Magnet for Division is an excelent Subject
Description for the messages that came with it.  I remember reading
about someone saying that having both SM/MOD and FM/MOD makes the ANS
Forth Standard weaker than having only one...  I didn't understand
why.

      BUT many others complain about the fact that the Standard
says that when  /  receives negative arguments the result is
unpredictable.  HOWEVER, in my view, this is not true for *any*
Forth ever written.  /  with negative arguments will give  SM/MOD
DROP  or  FM/MOD DROP  , right?  And this is not what is said by
BASIS 12.  BASIS 12 says that  20 -10 /  can give me 7! Or 130, or 0
et cetera.

      Well, when I write a program, I am not usually interested in
whether  /  is symmetric or floored, but I certainly expect that  20
-10 /  will give me -2.  And that  25 -10 /  will give me -2 or -3.
And I think that TC members expect that too.  If I am right, it was
only bad writting of the Standard (although bad writting of a
Standard cannot be considered as "ONLY").  And, if this is the case,
what is needed is just a rewrite of this section (and more care in
the future). *BUT*, if this is not the case, then I really condemn
the way things were done.

      Also, if the people who are complaining about division are not
complaining about this, I would like to hear (read) more specific
arguments.  I just cannot understand why SM/MOD and FM/MOD cannot
exist, and why  /  cannot be implementation defined (if we are sure
that it will be symmetric or floored, but not unpredictable).

      As I said above, I am not usually interested in the kind of
division I have.  But sometimes I need to know what kind of division
it is.  That is why I approve of things like SM/MOD, FM/MOD and
predictable result for  ... 0 /MOD  .  They give me a solid ground.
And I don't need to worry about rewritting code if the Forth I use
becomes unavaible for the Computer Enviroment I *MUST* to use.

      Trying to be clear,
                         (8-DCS)

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DCS@CIC.UNB.ANDF.BR                           Daniel C. Sobral
UNBCIC@BRFAPESP.BITNET                            (8-DCS)

                          "Ah, but there are always rules to break..."
                                         - The Vampire Lestat
                                     in The Queen of the Damned
                                     by Anne Rice
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