The #haskell mooc I'm doing is introducing IO but imho not very well.
I'm confused by the following snippet:
-------
ghci> val1 <- putStrLn "hello"
hello
ghci> val1
()
ghci> val2 = putStrLn "bye"
ghci> val2
bye
-----
val2 is easy I think. val2 is putStrLn "bye" and when prompted to represent itself the output is "bye", I guess the IO is "executed".
but val1 I don't get.
what is <- and why does it produce and output on the repl? and what is () ?
Tariq /
npub1xs…ctf6m
2025-04-15 14:31:07
Author Public Key
npub1xsrfffw8z907pyv0ulkfqwrcvkfw8qz0rg8y2l37p8gran76m34s2ctf6mSeen on
wss://relay.mostr.pubPublished at
2025-04-15 14:31:07Event JSON
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