On Tue, Nov 16, 2010 at 11:04:05PM +0200, Yitzchak Gale wrote:
Ian Lynagh wrote:
Proposal: Improve Read Integer http://hackage.haskell.org/trac/ghc/ticket/4500 Currently, according to H98, H2010, GHC and hugs, reads "1.2" :: [(Integer, String)] is [] whereas I would expect it to be [(1,".2")] http://hackage.haskell.org/trac/ghc/attachment/ticket/4500/read-integer.dpat...
This is a good change. But for GHC the patch is not complete. It needs to provide the old behavior in H98 and H2010 mode.
To do this we'd have to have a separate Integer type in haskell98/haskell2010, and therefore separate definitions of all classes and functions whose types contain Integer, and different default type defaulting. I doubt anyone relies on the current behaviour, and I think it's just an oversight (i.e. bug) in the language definition anyway. So I suggest we shouldn't be strictly backwards compatible in this case. Thanks Ian