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You're right, but ST is also implemented using unsafePerformIO. The larger point is that you don't need to dress up a type signature with ST or IO just to use
by pauldirac137 10y ago
You're right, but ST is also implemented using unsafePerformIO. The larger point is that you don't need to dress up a type signature with ST or IO just to use imperative code internally which can't leak out to the user level. Whether this is good or bad is a matter for debate, but used judiciously I think it's good.