1 files changed, 31 insertions, 0 deletions
diff --git a/Pattern.hs b/Pattern.hs
new file mode 100644
index 0000000..2a6007d
--- /dev/null
+++ b/Pattern.hs
@@ -0,0 +1,31 @@
+module Pattern where
+
+import Data.Char
+import Data.Text.Lazy (Text)
+import qualified Data.Text.Lazy as T
+
+
+data Pattern = Pattern Text [Origin]
+  deriving (Show)
+
+data Origin = OCopy
+            | ONew Text
+  deriving (Show)
+
+parsePattern :: String -> Either String Pattern
+parsePattern str = do
+    (constr, args) <- case words str of
+      [] -> Left "Empty match pattern"
+      constr : args -> return (constr, args)
+    args' <- traverse parseArg args
+    return (Pattern (T.pack constr) args')
+  where
+    parseArg :: String -> Either String Origin
+    parseArg ('*':name) | isValid name = Right (ONew (T.pack name))
+                        | otherwise = Left ("Invalid type param name '" ++ name ++ "'")
+    parseArg name | isValid name = Right OCopy
+                  | otherwise = Left ("Invalid type param name '" ++ name ++ "'")
+
+    isValid :: String -> Bool
+    isValid "" = False
+    isValid (hd:cs) = isLower hd && all (\c -> isAlpha c || c `elem` "'_") cs