To summarize the design we've converged upon during the discussion period for Ian: We want to add
class Bits b where bitSizeMaybe :: b -> Maybe Int
and deprecate, but not remove bitSize this iteration, and make a separate class FiniteBits for things with a finite, fixed number of bits:
class Bits b => FiniteBits b where finiteBitSize :: b -> Int finiteBitSize = bitSize
The former permits safer access to bitSize while allowing applications that
can deal with infinite structures to run, the latter permits safer access
to bitSize while allowing applications that cannot deal with infinite
structures to know that they aren't dealing with Integer or somebody's
Natural data type.
-Edward
On Wed, Aug 22, 2012 at 5:19 PM, Ian Lynagh
On Mon, Aug 13, 2012 at 06:42:54PM -0400, Edward Kmett wrote:
class Bits b where perhapsBitSize :: b -> Maybe Int ...
I am not wedded to the perhapsBitSize name
I've lost track of where this proposal is, but if we do end up with a Maybe function then I think it should be called maybeBitSize or bitSizeMaybe. The only analogous example in the core libraries that I can think of OTTOMH is Text.Read.readMaybe.
Thanks IAn
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