deemp · May 25, 2022 07:32 · May 25, 2022 · May 25, 2022 · May 25, 2022
diff --git a/Lib.hs b/Lib.hs
@@ -30,3 +30,16 @@ main = do
 
     customInt :: Parser Int
     customInt = read <$> many digitChar
+
+{-
+ghci> main
+(11111,333)
+
+
+1:5:
+  |
+1 | 1111
+  |     ^
+unexpected end of input
+expecting Limited input: 5 characters
+-}
diff --git a/Lib.hs b/Lib.hs
@@ -30,5 +30,3 @@ main = do
 
     customInt :: Parser Int
     customInt = read <$> many digitChar
-    -- customInt :: Parser Int -- NOTE: can't change this fn
-    -- customInt = many digitChar
diff --git a/Lib.hs b/Lib.hs
@@ -0,0 +1,34 @@
+{-# LANGUAGE LambdaCase #-}
+module Lib
+where
+
+import Text.Megaparsec 
+import Data.Void (Void)
+import Text.Megaparsec.Char (digitChar)
+import Data.Function ((&))
+
+type Parser = Parsec Void String
+
+main :: IO ()
+main = do
+  let input = "11111333"
+  parse p "p" input & \case
+    Left e -> error $ show e
+    Right r -> print r -- should print (11111, 333)
+  return ()
+  where
+    p :: Parser (Int, Int)
+    p =
+      do
+        l <- takeP (Just "Limited input: 5 characters") 5
+        l' <- takeRest
+        setInput l
+        a <- customInt-- TODO limit input to 5 characters just for this `customInt`
+        setInput l'
+        b <- customInt -- take the remaining 3 (already limited)
+        return (a, b)
+
+    customInt :: Parser Int
+    customInt = read <$> many digitChar
+    -- customInt :: Parser Int -- NOTE: can't change this fn
+    -- customInt = many digitChar
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