Fixed compilation issues

src/Interpreter.hs

@@ -4,6 +4,7 @@ module Interpreter where
 import Data.Maybe (catMaybes)
 
 data Instruction = TapeLeft | TapeRight | Add | Sub | Out | In | LoopStart | LoopEnd
+    deriving (Eq, Show)
 
 parseInstr :: Char -> Maybe Instruction
 parseInstr '<' = Just TapeLeft
@@ -16,7 +17,7 @@ parseInstr '[' = Just LoopStart
 parseInstr ']' = Just LoopEnd
 parseInstr _ = Nothing
 
-newtype Byte = Byte Int
+newtype Byte = Byte Int deriving (Eq, Ord, Read, Show)
 chr :: Byte -> Char
 chr (Byte i) = toEnum i :: Char
 
@@ -30,20 +31,18 @@ decr (Byte i) = Byte (i - 1)
 
 type Tape = [Byte]
 type Program = [Instruction]
-type IP = Int
-type DP = Int
 
 data ProgState = ProgState {
     tape :: Tape,
-    dp :: DP,
+    dp :: Int,
     output :: String,
     program :: Program,
-    ip :: IP }
+    ip :: Int }
 
 toProgram :: String -> [Instruction]
 toProgram s = catMaybes $ fmap parseInstr s
 
-tapeHelp :: Tape -> DP -> (Byte -> Byte) -> Tape
+tapeHelp :: Tape -> Int -> (Byte -> Byte) -> Tape
 tapeHelp (t:tt) 0 alter = alter t : tt
 tapeHelp (t:tt) dp alter = t : (tapeHelp tt dp alter)
 
@@ -53,8 +52,8 @@ errorDesc :: Error -> String
 errorDesc NegTape = "ERROR: '<' not working. Cannot access negative tape positions."
 errorDesc LoopNoMatch = "ERROR: '[' or ']' not working. Matching parenthesis not found."
 
-incrIP :: ProgState -> ProgState
+incrInt :: ProgState -> ProgState
-incrIP p = p { ip = ip p + 1 }
+incrInt p = p { ip = ip p + 1 }
 
 execAdd :: ProgState -> Either Error ProgState
 execAdd p = Right p { tape = newTape }
@@ -78,13 +77,12 @@ execOut p = Right p { output = output p ++ [chr char]}
 
 data WalkingDirection = Forward | Backward
 
-
+findMatching :: Program -> Int -> WalkingDirection -> Maybe Int
-findMatching :: Program -> DP -> WalkingDirection -> Maybe IP
 findMatching prg start wd = case wd of
                  Forward -> fmHelper start 0 LoopEnd LoopStart (+1) (length prg)
-                 Backward -> fmHelper start 0 LoopStart LoopEnd (-1) 0
+                 Backward -> fmHelper start 0 LoopStart LoopEnd (-1+) 0
-        where fmHelper :: IP -> Int -> Instruction -> Instruction -> (IP -> IP)
+        where fmHelper :: Int -> Int -> Instruction -> Instruction -> (Int -> Int)
-                -> Int -> Maybe DP
+                -> Int -> Maybe Int
               fmHelper s acc b ob upd limit
                 | acc == 0 && c == b = Just s
                 | c == b             = fmHelper (upd s) (acc - 1) b ob upd limit
@@ -94,11 +92,11 @@ findMatching prg start wd = case wd of
                 where c = prg !! start
 
 execLoopStart :: ProgState -> Either Error ProgState
-execLoopStart w = case newIP of
+execLoopStart w = case newInt of
             Just n -> Right w { ip = n }
             Nothing -> Left LoopNoMatch
-    where jump = (tape w !! dp w) == 0
+    where jump = (tape w !! dp w) == Byte 0
           posOrF = if jump then findMatching (program w) (ip w) Forward else Just $ ip w
-          newIP = fmap (+1) posOrF
+          newInt = fmap (+1) posOrF