On Fri, Apr 30, 2010 at 09:37:39PM +0100, Simon Marlow wrote: > On 30/04/10 13:19, Malcolm Wallace wrote: >>> 4. Provide a haskell2010 package and a base2010 package that >>> re-exports all of base except the modules that overlap with >>> haskell2010. You can either use haskell2010, >>> haskell2010+base2010, or base. This is a bit like (1), but >>> avoids the need for shadowing by using package re-exports, >>> on the other hand confusion could well arise due to the >>> strange base2010 package, and some people would surely try >>> to use haskell2010 + base and run into difficulties. >> >> In many ways this corresponds to my preferred solution, although I would >> rephrase it thus: >> >> * Deprecate use of the "base" package, (I do not mean to remove "base", >> just to freeze it, and discourage its general use.) >> * Create a new "haskell2010" package (for ghc this will be built on topcommon >> of "base", but other compilers might make a different choice). >> * Create a new "portablebase" package which contains (or re-exports) >> all of the remaining useful and portable parts of the current "base" >> _and_ "haskell2010". >> * Create a new "ghcextras" package which re-exports (or defines afresh) >> all of the useful but non-portable parts of the current "base". > > So it seems this is closer to option (2) in my message, because > portablebase and haskell2010 overlap, and are therefore mutually > exclusive, whereas in (4) haskell2010 and base2010 are non-overlapping - > that's the crucial difference.
If they are non-overlapping, how would a new Data.List function be added? Or an existing Data.List function be altered? No matter what solution is chosen, changes to datatypes or classes seem likely to be troublesome. I think the library change plans are underdeveloped, the libraries should be unchanged in H2010, and we should resolve this issue before changing them in a future language revision. That would keep other options open, such as the report standardising Haskell2011.Data.List rather than Data.List, etc. > I described this as a non-option because I thought trying to use the > packages together might be a common problem that leads to obscure error > messages about ambiguous modules, but perhaps it's not that bad, or at > least not worse than the other solutions. Direct imports of base* and haskell* could be (dis)allowed by the implementation depending on whether it is in "Haskell 2010 mode" or not. > We hope in the future that the set of libraries standardised in the > report grows beyond what we have in base currently Oh, I thought the plan was for library standardisation in the report to be reduced, with perhaps the Haskell Platform becoming the new library standardisation effort. Thanks Ian _______________________________________________ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime
