On 5/5/08, Brandon S. Allbery KF8NH <[EMAIL PROTECTED]> wrote: > The functional dependency "MyString m c | m -> c" tells GHC that any > specific "m" determines a specific "c". It doesn't matter what the type is > here, since it's not used in the definition of compareStr; but it must be > possible to know that the same "c" is being used in both arguments. Given > this, it can fix "MyString m c" knowing only "m" and as a result the > function typechecks.
Although this still makes it impossible to call zEquals for the same reason; you need a dependency in both directions for it to make sense. -- ryan _______________________________________________ Haskell-Cafe mailing list [email protected] http://www.haskell.org/mailman/listinfo/haskell-cafe
