[armedbear-devel] long

[Alessio Stalla]

On Tue, Mar 16, 2010 at 4:41 PM, Alan Ruttenberg
<alanruttenberg at gmail.com> wrote:
>
> On Mar 16, 2010, at 8:47 AM, dmiles at users.sourceforge.net wrote:
>
>> This is because ABCL:
>> Fixnum => int
>> Bignum => BigInteger
>>
>> ABCL does not have a 'long' type so it is normal workaround to produce
>> a new 'long in your case.
>>
>> So depends who is desiring: There is no real spec other than Allegro
>> http://www.franz.com/support/documentation/8.0/doc/jlinker.htm#data=types-conversions-3
>> But Allegro spec here is lossy..
>> (meaning if you went from a Lisp Bignum->Java->Lisp.. the number would
>> scaled back to Long.MAX_VALUE)  So their spec is even more
>> undesirable.
>
> Agreed.
>
>> It would be possible that when the Bignum is within normal java long
>> range the javaInstance() could return a java.lang.Long instead.
>>
>> Does everyone think this would be better behavior than current ABCL and Allegro?
>
> I'm thinking it would be. However, given that there is a workaround I wouldn't put it as high priority - more as a cleanup.

I think it would be, too. It's also arguably more efficient to
manipulate Longs than BigIntegers. However, doing so requires that we
also implement promotion, I mean, if a calculation result overflows
longs it should be automatically upgraded to big integer. Java does
not do anything like that, so I believe we must do it ourselves.

Alessio

> -Alan
>
>>
>>
>> On Mon, Mar 15, 2010 at 11:47 PM, Alan Ruttenberg
>> <alanruttenberg at gmail.com> wrote:
>>>
>>> Am I right to observe that abcl coerces any number > fixnum size to bigint?
>>> I'm having trouble calling a java method that takes a long. I seem to
>>> have worked around it calling the method with (new 'long
>>> "9223372036854775807") rather than 9223372036854775807 .
>>>
>>> Is this the desired behavior?
>>>
>>> -Alan
>>>
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>
>
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