[squeak-dev] 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 cellier a écrit :
> Paolo Bonzini a écrit :
>>> However, looking at the source, apart accessors, some methods will 
>>> hardly ever change, like:
>>> Integer>>bitInvert
>>>     ^-1-self
>>> 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 1-b 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 copyright-able 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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