29 Dec
2011
29 Dec
'11
8:42 p.m.
On Thursday 29 December 2011, 21:25:31, Peter Hall wrote:
If I have something like this
main = do args <- getArgs let file = args !! 0 -- etc...
And I run it without any arguments, I get an error message like this: "Prelude.(!!): index too large".
What's the best way to handle an error like this to give a better message back to the user?
main = do args <- getArgs case args of [] -> complain _ -> happiness or args <- getArgs if null args then complain else happiness