Keith Wansbrough <[EMAIL PROTECTED]> writes: > > In article <[EMAIL PROTECTED]>, > > [EMAIL PROTECTED] (Carl R. Witty) wrote: > > > > > Here's a hand-waving argument that you need either Typeable (or > > > something else that has a run-time concrete representation of types) > > > or ST/STRef (or something else, probably monadic, that can track > > > unique objects) to do this. > > > > George Russell already showed this, didn't he? You can implement > > Typeable given type-safe MRefs, and you can implement type-safe MRefs > > given Typeable. > > But George Russell's implementation relied on looking up something in > one map with a key obtained from another map. I thought type-safe > MRefs should disallow this.
If you use Simon PJ's type signatures, you can't really disallow using a key from one map with another map. Carl Witty _______________________________________________ Haskell mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell
