Haskell-prime

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March 2010

4 participants
2 discussions

Re: Deprecating haskell98 module aliases
by Simon Marlow 17 Mar '10

17 Mar '10

On 09/03/2010 12:11, Malcolm Wallace wrote: >> And regarding guest's comments, doesn't the Haskell 2010 standard[1] >> count as an "actual language standard"? If not, then what is it and >> why isn't it one? > > Haskell 2010 has been decided, but the Language Report itself has not > yet been published. So yes, it is a standard, but not one you can refer > to (yet). > > IIRC, H'2010 makes no changes to the Libraries section of the Report. > There was a proposal for 2010 to update the names of the libraries, to > their new hierarchical forms. It was not accepted. Thus, the Haskell'98 > names are still part of the official 2010 language standard, if I am not > mistaken. The discussion didn't result in a concrete proposal, but there was general agreement that we should remove Directory System Time Locale CPUTime Random and update the others to use hierarchical names: 1. Ratio keep as Data.Ratio 2. Complex keep as Data.Complex 3. Numeric keep as Numeric (?) 4. Ix keep as Data.Ix 5. Array keep as Data.Array 6. List keep as Data.List 7. Maybe keep as Data.Maybe 8. Char keep as Data.Char 9. Monad keep as Control.Monad 10. IO keep as System.IO and the FFI libraries would be added as CError -> Foreign.C.Error CForeign -> Foreign.C CString -> Foreign.C.C.String CTypes -> Foreign.C.Types ForeignPtr -> Foreign.ForeignPtr Int -> Data.Int MarshalAlloc -> Foreign.Marshal.Alloc MarshalArray -> Foreign.Marshal.Array MarshalError -> Foreign.Marshal.Error MarshalUtils -> Foreign.Marshal.Utils StablePtr -> Foreign.StablePtr Storable -> Foreign.Storable Word -> Data.Word (this proposal wasn't discussed publicly, unfortunately. I think that was an oversight.) I was actually planning to look at doing this during the H2010 report update. However, updating the libraries in the report to use the hierarchical names actually gives us a slight problem, in that we then have to provide those modules with exactly those interfaces for ever, presumably via some well-known package. The module names overlap with base, so we'd have to do some package reorganisation. Things could get painful really fast. I'm tempted to not do this in H2010, but defer it until we've really thought about how to manage the transition and future updates. I would like to remove the old superseded modules though: Directory, Time, System, Random, Locale, CPUTime. That would be an easy change, and we can provide a haskell2010 package exporting just the remaining modules. Cheers, Simon

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showing Ratios
by Doug McIlroy 02 Mar '10

02 Mar '10

Very minor library change to promote readability of output: eliminate spaces in the string representation of Ratios. Currently, a Ratio appears as a pair separated by " % ". The spaces that flank "%" make for confusing output. Example: [1 % 2,1 % 3,1 % 4,1 % 5,1 % 6] The spaces suggest that "," binds more tightly than "%". I claim that [1%2,1%3,1%4,1%5,1%6] is much more readable. It also saves paper and/or screen area. I suspect that the spaces came in to make it easier to find the division point in a lugubrious Ratio like 123456789%987654321 True enough, but such numbers are too incomprehensible to get much scrutiny anyway. I, at least, find that all I do with Ratios much more complicated than 355%113 is squirrel them away in tables that only a computer is likely to read seriously, or edit them into some other form, e.g. for Sloane's Encyclopedia of Integer Sequences. Doug McIlroy

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