Move parser to separate file

app/Main.hs

@@ -1,53 +1,10 @@
 module Main (main) where
 
-import Control.Monad.Combinators.Expr
-import Data.Void (Void)
+import Parser.Equation
 import System.Environment
 import Text.Megaparsec
-import Text.Megaparsec.Char as C
-import Text.Megaparsec.Char.Lexer as L
-
-type Parser = Parsec Void String
-
-data Expr
-  = Int Int
-  | Add Expr Expr
-  | Sub Expr Expr
-  | Mul Expr Expr
-  | Div Expr Expr
-  deriving (Show)
-
-lexemeParser :: Parser a -> Parser a
-lexemeParser = L.lexeme C.space
-
-symbolParser :: String -> Parser String
-symbolParser = L.symbol C.space
-
-intParser :: Parser Int
-intParser = lexemeParser L.decimal
-
-term :: Parser Expr
-term = Int <$> intParser
-
-table :: [[Operator Parser Expr]]
-table =
-  [ [ binaryOp "*" Mul,
-      binaryOp "/" Div
-    ],
-    [ binaryOp "+" Add,
-      binaryOp "-" Sub
-    ]
-  ]
-
-binaryOp name f = InfixL (f <$ symbolParser name)
-
-expr :: Parser Expr
-expr = makeExprParser term table
-
-parseExpr :: String -> Either (ParseErrorBundle String Void) Expr
-parseExpr = parse (C.space *> expr <* eof) ""
 
 -- main :: IO ()
 main = do
   input <- fmap head getArgs
-  parseTest expr input
+  parseTest equationParser input

app/Parser/Equation.hs

@@ -0,0 +1,49 @@
+module Parser.Equation (equationParser) where
+
+import Control.Monad.Combinators.Expr
+import Data.Void (Void)
+import Text.Megaparsec
+import Text.Megaparsec.Char as C
+import Text.Megaparsec.Char.Lexer as L
+
+type Parser = Parsec Void String
+
+data Expr
+  = Int Int
+  | Add Expr Expr
+  | Sub Expr Expr
+  | Mul Expr Expr
+  | Div Expr Expr
+  deriving (Show)
+
+lexemeParser :: Parser a -> Parser a
+lexemeParser = L.lexeme C.space
+
+symbolParser :: String -> Parser String
+symbolParser = L.symbol C.space
+
+intParser :: Parser Int
+intParser = lexemeParser L.decimal
+
+term :: Parser Expr
+term = Int <$> intParser
+
+table :: [[Operator Parser Expr]]
+table =
+  [ [ binaryOp "*" Mul,
+      binaryOp "/" Div
+    ],
+    [ binaryOp "+" Add,
+      binaryOp "-" Sub
+    ]
+  ]
+
+binaryOp name f = InfixL (f <$ symbolParser name)
+
+expr :: Parser Expr
+expr = makeExprParser term table
+
+parseExpr :: String -> Either (ParseErrorBundle String Void) Expr
+parseExpr = parse (C.space *> expr <* eof) ""
+
+equationParser = expr