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NNTP-Posting-Date: Sun, 24 Jul 2011 12:54:49 -0500
Date: Sun, 24 Jul 2011 10:54:44 -0700
From: Patricia Shanahan <pats@acm.org>
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Subject: Re: Arithmetic overflow checking
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On 7/24/2011 10:40 AM, markspace wrote:
> On 7/24/2011 9:16 AM, Patricia Shanahan wrote:
>> I think it might be better to create a marker interface
>> java.math.Arithmetic. I do like the idea of a fixed mapping from
>> operators to method names that are normal identifiers.
>
>
> I'd be concerned that a marker interface could be abused.
>
> public abstract class BaseNumber extends Number {
> public abstract BaseNumber add( Number n );
> public abstract BaseNumber subtract( Number n );
> public abstract BaseNumber mul( Number n );
> public abstract BaseNumber[] div( Number n );
> public abstract BaseNumber modulo( Number n );
> }
>
> Then restrict operator overloading to a class like BaseNumber and its
> subclasses. Some classes in the existing Java API like BigDecimal may
> need to also extend BaseNumber.

Whatever is done can, and will, be abused. People will just make their
non-arithmetic classes for which they want "+" extend BaseNumber, and
meanwhile complex would be forced to provide a meaningless conversion to
byte.

Patricia