[squeakdev] Re: [ANN] Kernel methods license audit
nicolas cellier
ncellier at ifrance.com
Fri Mar 21 21:43:37 UTC 2008
Ah and of course, all those bit ops have already primitive
implementation with BitBlt, just have to write wrappers...
A tainted squeakish solution for sure...
Nicolas
nicolas cellier a écrit :
> Paolo Bonzini a écrit :
>>
>>> However, looking at the source, apart accessors, some methods will
>>> hardly ever change, like:
>>> Integer>>bitInvert
>>> ^1self
>>>
>>> There is no added value in such method but very obvious algorithm:
>>> two complement: bitinvert the digits, and add 1
>>> => bitInvert: take two complement, and subtract 1
>>
>
> Another much simpler view is that 1 is an infinite sequence of
> ...1111111111111111111
>
> Subtracting any integer is just like performing 1b on each bit b
> because there is not any chance to raise a carry.
>
> 1111111111 
> 1010010111
> 
> 0101101000
>
>> This could become "^self bitXor: 1", at least if bitXor does not use
>> bitInvert. :)
>>
>
> Yes, that's a good solution that would work (though 7x slower in squeak
> for LargeInteger, because not primitive).
>
> But what i meant is that rewriting a single obvious method does not make
> much sense, since it's not really copyrightable by itself.
>
>>> The trick is not here, it is in pretending LargeNegativeInteger are
>>> stored in two complements, what they are not...
>>> So the trick is in all the bitOr:, bitAnd:, bitXor:, bitShift:
>>> implementations, as a whole.
>>
>> If you want a >0% chance to have different code, look at libgst/mpz.c
>> from GNU Smalltalk. It contains the exact same algorithms written in
>> C (so don't be afraid of tainting anything with anything). And XOR
>> does not use NOT so you get a chance to rewrite #bitInvert too. :)
>>
>> Paolo
>>
>>
>
> Yes, it is possible to rewrite the whole thing if REALLY necessary.
> That makes a little more sense than a single method.
>
> However, taking from GPL, to transform SqueakL into MIT... :)
> This adds to the total nonsense of licence and copyrights...
> Sisyphe is still very modern. Unless it's more like Danaids, you fill
> the image with code, but there is a licence leakage that let it flow out.
> Kind of missinterpretation of "dynamic" language i presume... (rewrite
> it every 5 years).
>
> Nicolas
>
>
>
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