Add remaining haskell book exercises

1 files changed, 59 insertions, 0 deletions

diff --git a/Haskell-book/14/morse/src/Main.hs b/Haskell-book/14/morse/src/Main.hs
new file mode 100644
index 0000000..1f73b90
--- /dev/null
+++ b/Haskell-book/14/morse/src/Main.hs
@@ -0,0 +1,59 @@
+module Main where
+
+import Control.Monad (forever, when)
+import Data.List (intercalate)
+import Data.Traversable (traverse)
+import Morse (stringToMorse, morseToChar)
+import System.Environment (getArgs)
+import System.Exit (exitFailure, exitSuccess)
+import System.IO (hGetLine, hIsEOF, stdin)
+
+convertToMorse :: IO ()
+convertToMorse = forever $ do
+    weAreDone <- hIsEOF stdin
+    when weAreDone exitSuccess
+
+    line <- hGetLine stdin
+    convertLine line
+
+    where convertLine line = do
+            let morse = stringToMorse line
+            case morse of
+                (Just str) -> putStrLn (intercalate " " str)
+                Nothing -> do
+                    putStrLn $ "ERROR: " ++ line
+                    exitFailure
+
+convertFromMorse :: IO ()
+convertFromMorse = forever $ do
+    weAreDone <- hIsEOF stdin
+    when weAreDone exitSuccess
+
+    line <- hGetLine stdin
+    convertLine line
+
+    where
+        convertLine line = do
+            let decoded :: Maybe String
+                decoded = traverse morseToChar (words line)
+
+            case decoded of
+                (Just s) -> putStrLn s
+                Nothing -> do
+                    putStrLn $ "ERROR: " ++ line
+                    exitFailure
+
+main :: IO ()
+main = do
+    mode <- getArgs
+    case mode of
+        [arg] ->
+            case arg of
+                "from" -> convertFromMorse
+                "to" -> convertToMorse
+                _ -> argError
+        _ -> argError
+
+    where argError = do
+            putStrLn "Please specify the first argument as being 'from' or 'to' morse, such as: morse to"
+            exitFailure
\ No newline at end of file