PRE-PROPOSAL: Simple operator overloading.

[rssh at gradsoft.com.ua]

>
> interface Addable<R, T> {
>      R add(T val);
> }
>
> class BigInteger implements
>      Addable<BigInteger, BigInteger>,
>      Addable<BigDecimal, BigDecimal>
> { ... }
>
> class BigDecimal implements
>      Addable<BigDecimal, BigInteger>,
>      Addable<BigDecimal, BigDecimal>
> { ... }
>
> I admit that doesn't look too elegant anymore, but I think it
> addresses the issue. Do you see any other problems there that I've
> overlooked?
>

 Yes, this can work.

> Cheers,
> Vil.
>
> Sent from my iPod
>
> On 26 Mar 2009, at 01:08, Daniel Cheng <j16sdiz at gmail.com> wrote:
>
>> On Wed, Mar 25, 2009 at 8:03 PM, Vilya Harvey
>> <vilya.harvey at gmail.com> wrote:
>>> I would love to see this, but I'd prefer it to be based on special
>>> interfaces rather than annotations. This would adhere to the
>>> principle, mentioned on this list a few times, that annotations
>>> shouldn't modify the results of the compiler.
>>>
>>> For example, if you implement the Addable (say) interface then your
>>> class can be used the '+' operator; or the Subtractable interface for
>>
>> We can't specify the return type if we use an interface.
>>
>> We may want to do something like this:
>>
>>        BigInteger + BigInteger     = BigInteger
>>        BigInteger + BigDecimal   = BigDecimal
>>        BigDecimal + BigInteger   = BigDecimal
>>        BigDecimal + BigDecimal = BigDecimal
>>
>> There is no way to implement this using interface.
>>
>>> the '-' operator. I'd imagine you would also want some grouping
>>> interfaces, to reduce the number of interface declarations required
>>> when overloading multiple operators (e.g. interface Artihmetic
>>> extends
>>> Addable, Subtractable etc.).
>>>
>>> Whatever form it takes though, it would be great to have this
>>> capability in Java!
>>>
>>> Vil.
>>>
>>>
>>> 2009/3/25  <rssh at gradsoft.com.ua>:
>>>> Permanent URL: http://docs.google.com/Doc?id=dhhvggr8_18djp85shk
>>>>
>>>> Probably too big, but anyway.
>>>>
>>>> As I remember, alternative proposal (made [] and []= syntax sugar on
>>>> well-known interfaces, as with for-each loop) still not submitted.
>>>> If
>>>> anybody want submit such proposal, then it is possible to reuse
>>>> JLS-changed for 15.26.1 from there.
>>>>
>>>>
>>>
>>>
>