io - Haskell: How to use a where statement under a do block

Question

This question already has an answer here: question from:https://stackoverflow.com/questions/65888624/haskell-how-to-use-a-where-statement-under-a-do-block

Answer 1

The bindings in the do block are opaque to the where statement after it, so you can't reference anything defined in the do block inside the where statement. You don't need to either, since you can use let directly inside do:

prog1 = do m <- getLine
           n <- getLine
           p <- getLine
           -- alternatively: [m, n, p] <- replicateM 3 getLine
           -- use a let statement
           let a = read m :: Int
           replicateM_ a (putStrLn n)
           replicateM_ a (putStrLn p)