3 files changed, 21 insertions, 15 deletions
diff --git a/src/parser/Core.hs b/src/parser/Core.hs
index 5928fe4..64e0b84 100644
--- a/src/parser/Core.hs
+++ b/src/parser/Core.hs
@@ -100,13 +100,16 @@ choice :: [Parser a] -> Parser a
 choice []     = empty
 choice (p:ps) = p <|> choice ps
 
--- verify :: (a -> Bool) -> Parser a -> Parser a
--- verify predicate p = do a <- p
---                         if predicate a then p else Parser (\_ -> Left "Bonjour")
+verify :: (a -> Bool) -> a -> Parser a
+verify predicate x = if predicate x then pure x else empty
 
--- Parse a string of alpha character, converted to lower case
-labelP :: Parser String
-labelP = (map toLower) <$> some (satisfyChar isAlpha)
+-- Parse a string of alpha character
+-- Convert to lower case and check that the label isn't `i`
+varLabelP :: Parser String
+varLabelP = (map toLower <$> some (satisfyChar isAlpha)) >>= verify (/= "i")
+
+funLabelP :: Parser String
+funLabelP = map toLower <$> some (satisfyChar isAlpha)
 
 
 floatP :: Parser Float
diff --git a/src/parser/Expr.hs b/src/parser/Expr.hs
index 5334578..b462197 100644
--- a/src/parser/Expr.hs
+++ b/src/parser/Expr.hs
@@ -27,20 +27,23 @@ termP =  operatorChoiceChain factorP
 
 factorP :: Parser Expr
 factorP =  choice [ parenthesizedExprP
-                  , imaginaryP
                   , Rational <$> floatP
                   , matrixP
-                  , Function <$> labelP <*> parenthesizedExprP
-                  , Variable <$> labelP
+                  , Function <$> funLabelP <*> parenthesizedExprP
+                  , imaginaryP
+                  , Variable <$> varLabelP
                   ] `chainl1` (infixOp "^" Exp)
     where
         parenthesizedExprP = parenthesis exprP
 
-        imaginaryP = Imaginary <$> (floatP <|> pure 1.0) <* char 'i'
+        imaginaryP = (Complex 0) <$> (floatP <|> pure 1.0) <* char 'i'
 
         -- Parse a matrix in the following format:
         -- [ [a, b]; [c, d] ]
         matrixP :: Parser Expr
-        matrixP = Matrix <$> brackets (matrixRowP `sepBy` (char ';'))
+        matrixP = Matrix <$> (brackets (matrixRowP `sepBy` (char ';')) >>= verify check)
             where matrixRowP = brackets (exprP `sepBy` (char ','))
                   brackets = between "[" "]"
+                  check rows
+                    | length rows == 0 = False
+                    | otherwise        = all ((length (head rows) ==) . length) $ tail rows
diff --git a/src/parser/Statement.hs b/src/parser/Statement.hs
index 889f24f..cfeabe1 100644
--- a/src/parser/Statement.hs
+++ b/src/parser/Statement.hs
@@ -14,15 +14,15 @@ data Statement
     | FunctionDeclaration String String Expr
 
 statementP :: Parser Statement
-statementP = functionDeclarationP <|> variableDeclarationP <|> polynomEvaluationP <|> evaluationP
+statementP = functionDeclarationP <|> variableDeclarationP <|> evaluationP <|> polynomEvaluationP
     where
         functionDeclarationP = FunctionDeclaration
-                                    <$> labelP
-                                    <*> parenthesis labelP
+                                    <$> funLabelP
+                                    <*> parenthesis varLabelP
                                     <*> (char '=' *> exprP)
 
         variableDeclarationP = VariableDeclaration
-                                    <$> labelP
+                                    <$> varLabelP
                                     <*> (char '=' *> exprP)
 
         polynomEvaluationP   = PolynomEvaluation <$>  exprP <*> (char '=' *> exprP <* char '?')