Sun, 21 May 2000 17:26:13 +1000, Fergus Henderson <[EMAIL PROTECTED]> pisze:
> But being able to import and/or re-export such symbols is necessary
> if you want to be able to implement an alternative prelude.
No: they can be simply always available, just as \ and let.
Standard Prelude has to be present anyway. You cannot construct
a reasonable implementation of Char from the thin air, and also
fromInteger must use a known to the compiler Integer type.
If they cannot be redefined, I see no reason to be able to export
and import them. And I think that they should not be redefined; lack
of some syntactic sugar is not a big loss if one makes a completely
new Prelude that does not have (>>=) as a method of Monad; lack of
cooperation with other libraries is a bigger loss: you cannot insert a
type without Ord instance to FiniteMap, even if it has some equivalent
of Ord from alternative Prelude.
Some prelude things are deeply wired-in. Show class (that it magical:
you can derive it) uses lists. It will not use an alternative list
type. You cannot replace a lower part of Prelude while keeping the
higher parts the same.
--
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