Control.Monad.ST.Unsafe.Compat

Unsafe operations

unsafeInterleaveST :: ST s a -> ST s a

unsafeInterleaveST allows an ST computation to be deferred lazily. When passed a value of type ST a, the ST computation will only be performed when the value of the a is demanded.

unsafeIOToST :: IO a -> ST s a

Convert an IO action to an ST action. This relies on IO and ST having the same representation modulo the constraint on the type of the state.

unsafeSTToIO :: ST s a -> IO a

Convert an ST action to an IO action. This relies on IO and ST having the same representation modulo the constraint on the type of the state.

For an example demonstrating why this is unsafe, see https://mail.haskell.org/pipermail/haskell-cafe/2009-April/060719.html