Obviously, the following function is impossible, because it is impossible to unwrap an IO value permanently (ignoring unsafePerformIO or similar):
In the GADTs section of the "Language extensions" chapter of the official OCaml docs, refutation cases of the form _ -> . are introduced. However, I thought that pattern-matching was already exhaustive, so I'm not sure when a refutation case is actually necessary.
I have a dataframe(df)I want to find all the strings that contain a certain sequence of characters, regardless of the order. For example if I have the string "CBC" or "CCB" I would like to get
I have a match expression that I would like to potentially return an error from. It seems that the compiler is not able to infer that the last case e is an Err(String) and requires the pattern to be explicit:
Ideally I'd like to write Haskell style pattern matching on the type level in Scala, something like this: