Thanks for all the help. I think things are much clearer now. And this bit:
main = do putStrLn "Hello, what is your name?"
name <- getLine
putStrLn ("Hello, " ++ name ++ "!")
Looks quite straight forward.
I just wrote my very first IO program with Haskell:
--//--
main = do
x <- getLine
putStrLn( show(length x) )
--//--
That's not so scary. The next thing I need to figure out is how to act
on the input data itself (not just its length). For example, if I wanted
a program to output the nth element of the fibonacci sequence:
--//--
$ ./fib 12
144
--//--
My first inclination would be to write it as:
--//--
main = do
x <- getLine
putStrLn( show(fib x) )
--//--
Of course that won't work because x is an IO String and 'fib' wants an
Int. To it looks like I need to do a conversion "IO a -> b" but from
what Cale said, that's not possible because it would defeat the
referential transparency of Haskell.
Hmm... there must be a way to solve this problem though...
In any event, thanks for the help. I'm learning :)
Cheers,
Daniel.
--
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