reallyUnsafe package:effectful-core

Utility for lifting IO computations of type

IO a -> IO b

to

Eff es a -> Eff es b

This function is really unsafe because:

• It can be used to introduce arbitrary IO actions into pure Eff computations.
• The IO computation must run its argument in a way that's perceived as sequential to the outside observer, e.g. in the same thread or in a worker thread that finishes before the argument is run again.

Warning: if you disregard the second point, you will experience weird bugs, data races or internal consistency check failures. When in doubt, use unsafeLiftMapIO, especially since this version saves only a simple safety check per call of reallyUnsafeLiftMapIO f.

Create an unlifting function. This function is really unsafe because:

• It can be used to introduce arbitrary IO actions into pure Eff computations.
• Unlifted Eff computations must be run in a way that's perceived as sequential to the outside observer, e.g. in the same thread as the caller of reallyUnsafeUnliftIO or in a worker thread that finishes before another unlifted computation is run.

Warning: if you disregard the second point, you will experience weird bugs, data races or internal consistency check failures. When in doubt, use unsafeSeqUnliftIO, especially since this version saves only a simple safety check per call of the unlifting function.