it was just an example where you can "bind" as "late" as possible a combination of symbols with its value... I like late binding :-) in this example allows you to get rigth results... and of course cosPiHalved is not the same as "a/b cos" where a is bound to pi and b to 2... it is not only for literals.
On Wed, Jul 8, 2009 at 3:59 PM, Igor Stasenko <[email protected]> wrote: > 2009/7/8 Hernan Wilkinson <[email protected]>: > > > >> > >> > >> > [...] and if you write 1.3, the object that represents that number > >> > is not going to be an instance of float but of scaledecimal or > >> > fraction or whatever, but not float... > >> > >> That only solves the issue of representing literals because: > >> > >> > >> > and all operations are made with exact representation. > >> > >> > >> > >> cannot be done for all operations: obvious ones like square root, log, > >> sin, etc and less obvious ones like #squared where you run out of > >> enough bits to maintain precision (in fixed-width implementations). > > > > not really... root, log, sin, etc could be messages that only inexact > > numbers know how to answer , so you want "2 sqrt", do "2 asFloat sqrt", > but > > for +, *, /, etc. they work as expected. > > We can also have better representations for number like pi. Why pi is > > instance of Float and not Pi? If pi is instance of Pi, then cos(pi/2) = 0 > > could be true... just a quick hack: > > Pi>>/ aNumber > > > > ^ Fraction numerator: self denominator: aNumber "Or maybe an object > > representing that Pi has been divided/multiplied, etc > > > > Fraction>>cos > > > > ^ numerator cosDividedWith: denominator > > > > Pi>>cosDividedWith: denominator > > > > ^denominator = 2 ifTrue: [ 0 ] ifFalse: [ ... ] > > > > and so on > > > > > don't forget to add > Pi>>mantisOfLength: numBits > > to compute the Pi up to given precision. :) > > > But your examples is not about computing a result, but rather predicting > it. > So why bother writing so much stuff , while you can just implement : > > Number>>cosPiHalved > ^ 0 > > :) > > >> > >> > >> > >> R > >> - > >> > >> > >> _______________________________________________ > >> Pharo-project mailing list > >> [email protected] > >> http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-project > > > > > > _______________________________________________ > > Pharo-project mailing list > > [email protected] > > http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-project > > > > > > -- > Best regards, > Igor Stasenko AKA sig. > > _______________________________________________ > Pharo-project mailing list > [email protected] > http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-project >
_______________________________________________ Pharo-project mailing list [email protected] http://lists.gforge.inria.fr/cgi-bin/mailman/listinfo/pharo-project
