On Fri, 2007-11-02 at 11:56 -0400, Brandon S. Allbery KF8NH wrote: > On Nov 2, 2007, at 11:51 , Jonathan Cast wrote: > > >> I will grant that hiding *World / RealWorld# inside IO is cleaner > >> from a practical standpoint, though. Just not from a semantic one. > > > > On the contrary. GHC's IO newtype isn't an implementation of IO in > > Haskell at all. It's an implementation in a language that has a > > Haskell-compatible subset, but that also has semantically bad > > constructs > > Differing viewpoints, I guess; from my angle, Clean's "uniqueness > constraint" looks like a hack hidden in the compiler.
Yeah. After all, the "uniqueness constraint" has a theory with an excellent pedigree (IIUC linear logic, whose proof theory Clean uses here, goes back at least to the 60s, and Wadler proposed linear types for IO before anybody had heard of monads). It's not some random hack somebody happened to notice would work, any more than existential types are. jcc _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
