Groups > comp.lang.java.programmer > #6530

Re: Arithmetic overflow checking

Newsgroups	comp.lang.java.programmer
From	Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at>
Subject	Re: Arithmetic overflow checking
References	(15 earlier) <IMBWp.68441$5v5.52239@newsfe11.iad> <slrnj2mdoi.6gl.avl@gamma.logic.tuwien.ac.at> <j0g1i4$nus$1@speranza.aioe.org> <ueidnUcxuMPT2LHTnZ2dnUVZ_uKdnZ2d@earthlink.com> <j0j5ie$v55$1@speranza.aioe.org>
Message-ID	<slrnj2qjgv.6gl.avl@gamma.logic.tuwien.ac.at> (permalink)
Date	2011-07-25 11:06 +0000

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Henderson <h1@g1.f1> wrote:
>> I think it might be better to create a marker interface
>> java.math.Arithmetic.
>
> That sneaks in arbitrary operator overloading through the back door, as 
> people slap "implements java.math.Arithmetic" on 
> "JFoobarSQLQueryEnumerator" and implement ".plus" for it. ;)

It's quite likely that the reviewer who inevitably will shoot the
programmer for this, will have the jury's sympathy and not be 
punished...  ;)

A more fundamental problem with operator overloading for "Arithmetic"
types is, when Arithmetic types can or cannot be mixed for a particular
operation.

Simple example:  what would be the sum of
BigInteger("123456789012345678901234567890123456789012") and some
Complex( 0.0 , Math.PI )?  Ok, preferences likely go towards
Complex as the result for this particular example, but there must
be some formalism as to how this addition would be actually
calculated: either there would have to be an over*load* of
.plus(...) for each and every other type, or there must be some
bottleneck like "double" through which unknown Arithmetic-
implementations for the right operand are going to be queezed to
perform the actual calculation.

Such cross-type-behaviour can be deliberately defined for a fixed
handful of new types, but not generally among any two implementors
(or subclasses) of some interface (or baseclass). (I anticipate 
that someone will now throw up .equals(), but that's of course
a much simpler matter ("just return false") with respect to
unrelated argument types.)

PS:
I have a faible for philosophical discussions of what new features
would or would not improve Java, and what dangers linger behind them.
I do not think, that any of this discussion or outcomes will have an
influence on what may or may not go into a new version of Java.

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Re: Arithmetic overflow checking Arne Vajhøj <arne@vajhoej.dk> - 2011-07-19 20:54 -0400
  Re: Arithmetic overflow checking markspace <-@.> - 2011-07-19 18:07 -0700
    Re: Arithmetic overflow checking Arne Vajhøj <arne@vajhoej.dk> - 2011-07-19 21:31 -0400
      Re: Arithmetic overflow checking Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-07-20 07:36 -0300
        Re: Arithmetic overflow checking RedGrittyBrick <RedGrittyBrick@spamweary.invalid> - 2011-07-20 11:58 +0100
          Re: Arithmetic overflow checking lewbloch <lewbloch@gmail.com> - 2011-07-20 09:51 -0700
            Re: Arithmetic overflow checking RedGrittyBrick <RedGrittyBrick@spamweary.invalid> - 2011-07-21 12:11 +0100
              Re: Arithmetic overflow checking Martin Gregorie <martin@address-in-sig.invalid> - 2011-07-21 12:43 +0000
                Re: Arithmetic overflow checking Tom McGlynn <taqmcglynn@googlemail.com> - 2011-07-21 07:15 -0700
              Re: Arithmetic overflow checking lewbloch <lewbloch@gmail.com> - 2011-07-21 07:35 -0700
                Re: Arithmetic overflow checking Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-07-21 15:38 +0000
                Re: Arithmetic overflow checking lewbloch <lewbloch@gmail.com> - 2011-07-21 09:03 -0700
                Re: Arithmetic overflow checking Joshua Cranmer <Pidgeot18@verizon.invalid> - 2011-07-21 12:00 -0700
                Re: Arithmetic overflow checking Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-07-22 17:16 +0000
                Re: Arithmetic overflow checking David Lamb <dalamb@cs.queensu.ca> - 2011-07-23 11:28 -0400
                Re: Arithmetic overflow checking Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-07-23 21:03 +0000
                Re: Arithmetic overflow checking Henderson <h1@g1.f1> - 2011-07-23 22:55 -0400
                Re: Arithmetic overflow checking Patricia Shanahan <pats@acm.org> - 2011-07-24 09:16 -0700
                Re: Arithmetic overflow checking markspace <-@.> - 2011-07-24 10:40 -0700
                Re: Arithmetic overflow checking Patricia Shanahan <pats@acm.org> - 2011-07-24 10:54 -0700
                Re: Arithmetic overflow checking markspace <-@.> - 2011-07-24 11:09 -0700
                Re: Arithmetic overflow checking Patricia Shanahan <pats@acm.org> - 2011-07-24 12:53 -0700
                Re: Arithmetic overflow checking markspace <-@.> - 2011-07-24 15:15 -0700
                Re: Arithmetic overflow checking Patricia Shanahan <pats@acm.org> - 2011-07-24 15:41 -0700
                Re: Arithmetic overflow checking Henderson <h1@g1.f1> - 2011-07-25 03:21 -0400
                Re: Arithmetic overflow checking Patricia Shanahan <pats@acm.org> - 2011-07-25 00:56 -0700
                Re: Arithmetic overflow checking Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-07-25 07:03 -0300
                Re: Arithmetic overflow checking Thomas Richter <thor@math.tu-berlin.de> - 2011-07-26 09:43 +0200
                Re: Arithmetic overflow checking Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-07-25 11:06 +0000
                Re: Arithmetic overflow checking Henderson <h1@g1.f1> - 2011-07-25 11:12 -0400
                Re: Arithmetic overflow checking Patricia Shanahan <pats@acm.org> - 2011-07-25 09:09 -0700
                Re: Arithmetic overflow checking Patricia Shanahan <pats@acm.org> - 2011-07-25 09:30 -0700
                Re: Arithmetic overflow checking David Lamb <dalamb@cs.queensu.ca> - 2011-07-25 13:33 -0400
                Re: Arithmetic overflow checking "John B. Matthews" <nospam@nospam.invalid> - 2011-07-26 03:04 -0400
                Re: Arithmetic overflow checking Joshua Cranmer <Pidgeot18@verizon.invalid> - 2011-07-26 03:28 -0400
                Re: Arithmetic overflow checking Henderson <h1@g1.f1> - 2011-07-26 04:53 -0400
                Re: Arithmetic overflow checking Joshua Cranmer <Pidgeot18@verizon.invalid> - 2011-07-26 11:35 -0400
                Re: Arithmetic overflow checking Patricia Shanahan <pats@acm.org> - 2011-07-26 10:48 -0700
                Re: Arithmetic overflow checking Arne Vajhøj <arne@vajhoej.dk> - 2011-07-21 17:00 -0400
        Re: Arithmetic overflow checking Arne Vajhøj <arne@vajhoej.dk> - 2011-07-20 19:50 -0400
          Re: Arithmetic overflow checking Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-07-20 23:21 -0300
            Re: Arithmetic overflow checking Martin Gregorie <martin@address-in-sig.invalid> - 2011-07-21 12:52 +0000
              Re: Arithmetic overflow checking Henderson <h1@g1.f1> - 2011-07-21 15:58 -0400
            Re: Arithmetic overflow checking Arne Vajhøj <arne@vajhoej.dk> - 2011-07-21 17:06 -0400
      Re: Arithmetic overflow checking Gene Wirchenko <genew@ocis.net> - 2011-07-20 14:35 -0700
        Re: Arithmetic overflow checking Arne Vajhøj <arne@vajhoej.dk> - 2011-07-20 18:22 -0400
          Re: Arithmetic overflow checking Gene Wirchenko <genew@ocis.net> - 2011-07-21 14:54 -0700

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