Proposal: Add hasBitSize to Data.Bits.Bits

[Ben Millwood]

Hold on, we /do/ get a different combinator, because we're introducing
this new typeclass anyway, and bitSize is being deprecated. So why not
stop excluding it from looking at its argument? Now's a better time
than later to do so :)

(Sorry this is late; I was originally going to comment to Henning that
we hadn't necessarily agreed on Fixed because of my argument, but then
realised someone had objected to my argument, but then realised that
that objection was possibly invalid).

On Tue, Aug 28, 2012 at 6:18 PM, Edward Kmett <ekmett at gmail.com> wrote:
> The problem is that right now bitSize is deliberately excluded from looking
> at its argument to determine the number of bits in it. You _really_ want a
> different combinator. Almost every user of bitSize is passing it undefined,
> not a real value.
>
>
> On Tue, Aug 28, 2012 at 12:07 PM, Ben Millwood <haskell at benmachine.co.uk>
> wrote:
>>
>> Wouldn't it be possible to have an instance Bits ByteString, or Vector
>> Bool or something, where the bitsize would depend on the bytestring
>> length, and hence wouldn't be fixed?
>>
>> (although if we're catering for that sort of use, the docs will need
>> to be changed)
>>
>> On Sun, Aug 26, 2012 at 9:53 PM, Henning Thielemann
>> <lemming at henning-thielemann.de> wrote:
>> >
>> > On Sun, 26 Aug 2012, Ian Lynagh wrote:
>> >
>> >> On Wed, Aug 22, 2012 at 07:49:49PM -0400, Edward Kmett wrote:
>> >>>
>> >>>
>> >>> 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
>> >
>> >
>> >
>> > Bit size is always finite in strict data types, isn't it? I suggest a
>> > name
>> > containing "Fixed".
>> >
>> >
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