Hi > I'm wondering how usually you parse command line arguments > list safely. If the given argument is wrong, the program > can still print out some error information instead of giving > something like
Either use reads instead, and deal with the case where there is no parse. Or use the safe library, on hackage, and something like: import Safe readNote "please enter a number" x Where if x is "test", you'll get: Program error: Prelude.read: no parse, please enter a number, on "test" Or use readDef: readDef (error "Please enter a number") x Which will just give you: Program error: Please enter a number Or, readMay, which will return a Nothing if you fail, which you can deal with as you wish. Thanks Neil _______________________________________________ Haskell-Cafe mailing list [email protected] http://www.haskell.org/mailman/listinfo/haskell-cafe
