This particular error was caused by method call syntax - because you can omit parenthesis around `functionCall arguments`, `RIn -1` got parsed as `RIn(-1)` and not `RIn - 1`.
As for the list of "pitfalls" \- the only thing that comes to mind is passing tuples to function calls `funcall(1, 2)` is a call for function with two parameters, while `funcall (1, 2)` is a call for function with single parameter that accepts tuple of two elements. Also for array access `arrayVar[12]` is not the same as `funcall [12]`
