On Mar 22, 2006, at 2:16 PM, David F. Place wrote:
Hi All,
I really appreciate all the help I received when I asked you to critique my PrefixMap module a few weeks ago. I think I am making good progress in correcting the "lisp" in my Haskell programming. I'll be very grateful to anyone who can take a glance at the attached short program and say if any unidiomatic usages pop out.
sudoku :: Sudoku -> IO () sudoku s = ((mapM_ putStrLn) . (check s) . (take 1) . solveSudoku) s
check puzzle [] = [showSudoku puzzle,"No solutions."] check puzzle [solution] | solution `solves` puzzle = ["Puzzle:",showSudoku puzzle,"Solution:",showSudoku solution] | otherwise = ["Program Error. Incorrect Solution!"]
That '(check s) . (take 1)' bit looks a little odd to me. I would simply have written 'check' to match like: check puzzle [] = <failure case> check puzzle (solution : _ ) = <success case> Also, I like to put off doing IO as long as possible, so I'd probably have 'sodoku' return a String or [String] and move the putStr into main. Its an easy way to make your code more reusable. Also, your parser is pretty hackish (but I suspect you knew that already). FYI, solveSudoku has a bug; if you enter an invalid puzzle it will return non-solutions.
It solves sudoku puzzles. (What pleasure do people get by doing these in their heads?!?)
I have no idea. Rob Dockins Speak softly and drive a Sherman tank. Laugh hard; it's a long way to the bank. -- TMBG