Marcin 'Qrczak' Kowalczyk writes: : | Since OO languages often use subtypes to emulate constructors of | algebraic types, they need downcasts. In Haskell it's perhaps less | needed but it's a pity that it's impossible to translate an OO | scheme which makes use of downcasts into Haskell in an extensible | way (algebraic types are "closed").
Hi. I'm curious about this impossibility. - Is it well known? If so, would someone please refer me to a paper or posting which explains it? - Does it just affect Haskell 98, or does it have deep implications for any future language extensions? - How does it relate to the alternative record mechanism idea you mentioned a while ago? http://haskell.org/pipermail/haskell/2000-December/000213.html Regards, Tom _______________________________________________ Haskell mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell