Rustom Mody
I have this from Peyton Jones awkward squad paper
getTwoChars :: IO (Char,Char) getTwoChars = do c1 <- getChar c2 <- getChar return (c1,c2)
Can someone explain what is happening here? *Main> getTwoChars ab ('a','b')
This seems perfectly fine. The getTwoChars action is one that will result in a 2-tuple of Chars, when run. The getChar action is a value of type IO Char, so it's an action that, when run, yields a Char. While defining an IO action like getTwoChars you can use other actions to build it. In the context of IO each action is executed in sequence (the two getChars) you have there, and the "<-" arrow is used to give their results a name, if you care about them. The "return x" action is just the action, which will yield x when run, so "return (c1, c2)" will yield the tuple in conformance to getTwoChar's type.
*Main> getTwoChars a ('\n','a')
This one seems really odd. Assuming that you typed "a" and then pressed the Return key, I don't know why it happens for you. For me it doesn't happen. I get the expected ('a', '\n'). Greets, Ertugrul -- nightmare = unsafePerformIO (getWrongWife >>= sex) http://ertes.de/