(Code)+main.hs for entrypoint of program

1 files changed, 66 insertions, 0 deletions

diff --git a/Main.hs b/Main.hs
new file mode 100644
index 0000000..9c6ab3f
--- /dev/null
+++ b/Main.hs
@@ -0,0 +1,66 @@
+import Math
+import System.Environment
+import Data.List
+import Text.Printf
+
+errorMessage :: String -> String
+
+errorMessage "" = "nd v1\nUsage: nd [-int, -prime, -factor, -hcf]"
+errorMessage reason = "nd v1\nFAILURE: " ++ reason ++ "\nUsage: nd [-int, -prime, -factor, -hcf]"
+
+flagHandlerF :: [String] -> Int -> String -> ([String] -> String) -> String
+
+flagHandlerF args (-1) error fmessage =
+  if (length args) == 0
+  then error
+  else
+    (fmessage args)
+
+flagHandlerF args nargs error fmessage =
+  if (length args) /= nargs
+  then error
+  else
+    (fmessage args)
+
+flagHandler :: String -> [String] -> String
+
+flagHandler "-prime" args =
+  flagHandlerF args (-1)
+    (errorMessage "-prime requires at least one integer argument")
+    (\args ->
+        foldl (++) "" [show y ++ ": isPrime=" ++ (show $ isPrime y)
+                    ++ "\n" | x <- args, let y = (read x) :: Int])
+
+flagHandler "-factor" args =
+  flagHandlerF args (-1)
+    (errorMessage "-factor requires at least one integer argument")
+    (\args ->
+        foldl (++) "" [show y ++ ": factors=" ++ show (factors $ y)
+                        | x <- args, let y = (read x) :: Int])
+
+flagHandler "-int" args =
+  flagHandlerF args (-1)
+    (errorMessage "-int requires at least one integer argument")
+    (\args ->
+        foldl (++) "" [show y ++ ": (isPrime=" ++ (show $ isPrime y)
+                        ++ ", factors=" ++ (show $ factors y)
+                        ++ ")\n" | x <- args, let y = (read x) :: Int])
+
+flagHandler "-hcf" args =
+  flagHandlerF args (2)
+    (errorMessage "-hcf requires two integer arguments")
+    (\args ->
+        let n       = (read $ head args) :: Int
+            m       = (read $ head $ tail args) :: Int
+            hcf     = head $ reverse $ intersect (factors n) (factors m) in
+        "hcf(" ++ show n ++ ", " ++ show m ++ "): hcf=" ++ show hcf)
+
+
+flagHandler _ _ = errorMessage "Didn't recognise flag"
+
+main = do
+  args <- getArgs
+  if (length args) == 0
+    then putStrLn $ errorMessage ""
+    else
+    putStrLn $ flagHandler (head args) (tail args)