Ulrich Schuster questions

• What is the idiomatic Haskell-way to act on predicates in IO?
• Add a missing property in a groovy @Canonical bean constructor call?
• What does it mean to "run" inside a monad?
• How can I compose error types in Haskell?
• Which permission does a docker named volume get upon mounting?
• Is IO a Free Monad?

Ulrich Schuster answers