Dmitry Astapov wrote (on 02-10-01 15:16 +0300): > > It seems like an appropriate page for aske newbie questions, isnt it? > > I was reading through Haskell tutroial > (http://www.di.uminho.pt/afp98/PAPERS/Tutorial.ps) and trying to do > exercises from there. I'm stuck in the first exercise for "Classes" chapter > (page 11). I need to define SetsAsLists as an instance of Set by supplying > definitions for all Set methods, but definitions I wrote led me to adding > additional constraints on "union" and "memeber" methods. Is it ok or it's > possible to define "union" and "member" without using "==" ?
It sure looks like an error to me. You definitely need equality on a collection A to define a set over A. I think your implementation is fine. -- Frank Atanassow, Information & Computing Sciences, Utrecht University Padualaan 14, PO Box 80.089, 3508 TB Utrecht, Netherlands Tel +31 (030) 253-3261 Fax +31 (030) 251-379 _______________________________________________ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe
