Control.Monad.ST.Unsafe

Copyright	(c) The University of Glasgow 2001
License	BSD-style (see the file libraries/base/LICENSE)
Maintainer	[email protected]
Stability	experimental
Portability	non-portable (requires universal quantification for runST)
Safe Haskell	Unsafe
Language	Haskell2010

Unsafe operations

unsafeInterleaveST :: ST s a -> ST s a Source

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.

unsafeDupableInterleaveST :: ST s a -> ST s a Source

unsafeDupableInterleaveST 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.

The computation may be performed multiple times by different threads, possibly at the same time. To prevent this, use unsafeInterleaveST instead.

Since: base-4.11

unsafeIOToST :: IO a -> ST s a Source

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

unsafeSTToIO :: ST s a -> IO a Source

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

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