1 files changed, 32 insertions, 18 deletions
diff --git a/src/parser/Expr.hs b/src/parser/Expr.hs
index 2d6937a..6a721f8 100644
--- a/src/parser/Expr.hs
+++ b/src/parser/Expr.hs
@@ -12,28 +12,42 @@ imaginaryP = Imaginary <$> (floatP <* char 'i')
 rationalP :: Parser Expr
 rationalP = Rational <$> floatP
 
+-- Parse a matrix in the following format:
+-- [ [a, b]; [c, d] ]
 matrixP :: Parser Expr
-matrixP = Matrix <$> (char '[' *> sepBy (char ';') matrixRowP <* char ']')
-    where matrixRowP = char '[' *> sepBy (char ',') exprP <* char ']'
+matrixP = Matrix <$> brackets (matrixRowP `sepBy` (char ';'))
+    where matrixRowP = brackets (exprP `sepBy` (char ','))
+          brackets = between "[" "]"
 
+
+-- Parse expression separated by one infix operator of the operator list
+operatorChoiceChain :: Parser a -> [Parser (a -> a -> a)] -> Parser a
+operatorChoiceChain x operators = x `chainl1` choice operators
+
+-- Parse an expression (lowest operator priority)
 exprP :: Parser Expr
-exprP = termP `chainl1` termOpP
-    where termOpP = infixOp "+" Add <|> infixOp "-" Sub
+exprP = operatorChoiceChain termP
+            [ infixOp "+" Add
+            , infixOp "-" Sub
+            ]
 
 termP :: Parser Expr
-termP =  factorP `chainl1` factorOpP
-    where factorOpP = infixOp "**" Dot <|> infixOp "*" Mul <|> infixOp "/" Div <|> infixOp "%" Mod
+termP =  operatorChoiceChain factorP
+            [ infixOp "**" Dot
+            , infixOp "*" Mul
+            , infixOp "/" Div
+            , infixOp "%" Mod
+            ]
 
 factorP :: Parser Expr
-factorP =  endpointP `chainl1` expOpP
-    where expOpP = infixOp "^" Exp
-
-          endpointP = parensExprP
-                      <|> imaginaryP
-                      <|> rationalP
-                      <|> matrixP
-                      <|> functionP
-                      <|> variableP
-              where variableP = Variable <$> alphaStringP
-                    functionP = Function <$> alphaStringP <*> parensExprP
-                    parensExprP = parenthesize exprP
+factorP =  choice [ parenthesizedExprP
+                  , imaginaryP
+                  , rationalP
+                  , matrixP
+                  , functionP
+                  , variableP
+                  ] `chainl1` (infixOp "^" Exp)
+
+    where variableP = Variable <$> alphaStringP
+          functionP = Function <$> alphaStringP <*> parenthesizedExprP
+          parenthesizedExprP = parenthesis exprP