3 ms·

> There are plenty of tricks you can not write on pure monads This made me curious, could you list some?

• marcosdumay 10y ago
  Anything that needs rewriting a memory address without losing time by allocation and garbage collection. Handling IO exceptions and masking them as different errors. Thread, process, or machine coordination in parallel execution.
  • pka 10y ago
    You don't need unsafePerformIO for any of these. > Anything that needs rewriting a memory address without losing time by allocation and garbage collection. ST gives you mutable references. Or just use IO.
    • marcosdumay 10y ago
      You need it for doing what the OP is talking about.