Am 16.02.2014 11:14, schrieb Herbert Valerio Riedel:
Hello *,
Right now, there seems to be no "defined" way to create a zero 'Bits'-value (w/o requiring also a 'Num' instance), that has all bits cleared without involving at least two operations from the 'Bits' class (e.g. `clearBit (bit 0) 0` or `let x = bit 0 in xor x x`).
OTOH, introducing a new method 'class Bits a where bitZero :: a' seems overkill to me.
However, "bit (-1)"
It would be better to forbid "bit (-1)" by the type system, if this would be possible. If only indices would be allowed that actually exist, then we would have a nice law like "popCount (bit n) == 1". I would not like that the exceptional "bit (-1)" becomes the blessed way to create zeros. An additional "zero" method with a default implementation would be the clean way.