evaluateHead :: ConditionalHead -> TeXParser Bool
evaluateHead (IfNum left rel right) =
  case rel of
    LessThan -> return $ left < right
    EqualTo -> return $ left == right
    GreaterThan -> return $ left > right
evaluateHead :: ConditionalHead -> TeXParser Bool
evaluateHead (IfNum left rel right) =
  case rel of
    LessThan -> return $ left < right
    EqualTo -> return $ left == right
    GreaterThan -> return $ left > right
evaluateHead (IfNum left rel right) =
  case rel of
    LessThan -> return $ left < right
    EqualTo -> return $ left == right
    GreaterThan -> return $ left > right