"or any other expression" To be more precise, any other expression with an appropriate type. That's `a` or `IO a`, where `a` is an instance of `Show`. Most t

"or any other expression" To be more precise, any other expression with an appropriate type. That's `a` or `IO a`, where `a` is an instance of `Show`. Most things that can reasonably be Shown already have a `Show` instance, but some things (like functions) can't really. This is relevant when the REPL shows an error like: <interactive>:2:1: No instance for (Show (t0 -> a0)) (maybe you haven't applied enough arguments to a function?) arising from a use of ‘print’ In the first argument of ‘print’, namely ‘it’ In a stmt of an interactive GHCi command: print it