In general, it's an implementation matter where to put these functions, rather than a major design choice. If one module is getting big and clumsy, then maybe splitting it into two would help. However, as you say we need to think about integer-simple too, so we should perhaps think about adding the same new functions to the 'integer-gmp' and 'integer-simple' packages. Then you would not need #ifdefs in GHC.Float, would you? s | -----Original Message----- | From: daniel.is.fischer@web.de [mailto:daniel.is.fischer@web.de] | Sent: 04 October 2010 15:01 | To: Simon Peyton-Jones; libraries@haskell.org | Subject: Re: Proposal: Better power for Rational | | On Monday 04 October 2010 11:57:06, Simon Peyton-Jones wrote: | > Henning | > | > | I'll try to create a patch, however I may need some assistance | > | compiling base libraries. | > | > Thank you. Creating a patch, attaching to a ticket with some rationale, | > and submitting it to the libraries list, is the best way to push your | > work over the hill and into the actual code base. I'm sure others will | > help. If you get stuck, yell! | > | > Daniel Fischer is working in this patch too. | > | > Simon | | Since I'm working on GHC.Float anyway, I'll include Henning's rounding etc. | code too. | | Speaking of GHC.Float, there are a few points where I would like some | guidance on where to put things. | | I could of course put everything in GHC.Float, but it's big already and I'd | prefer not to clutter it up further. | | For toRational, to avoid wasting time in gcd, I need an array for the | number of trailing 0-bits in a byte. Also, since bit-fiddling of Integers | is considerably slower than for fixed width types, I'd need to import | GHC.IntWord64 since a Double mantissa won't fit in an Int on 32-bit | systems. This could go into GHC.Float or into a GHC.Float.Utils module. | | For fromRational, I need a fast integerLog2. For that, I need access to the | internal representation of Integers when using integer-gmp and an | alternative implementation for integer-simple (which would be much slower, | but if you use integer-simple, performance probably isn't your foremost | concern). I might need a few more odds and ends if special-casing for the | results of toRational (whose denominator is a power of 2) proves to be a | gain. | | Putting all the auxiliary stuff in GHC.Float wrapped in #ifdefs is IMO an | appalling idea. | | integerLog2 and more generally integerLogBase are useful enough to be added | to GHC.Integer (Int/Word is not yet available, so it'd be the '#' versions, | where would the wrappers returning an Int or Word go?). | If I need the stuff for special casing, my preferred solution would be to | put it in GHC.Integer.Variant.Internals or add a small dedicated module for | them to the package. | | So what's the best place to put stuff?