Parser missing something

50069

When the cursor is between the parenthesis,
I get a MNU RBParseErrorNode>>addParenthesis:
when typing anything

drawOn: aCanvas
        |lines|
        super drawOn: aCanvas.
        lines := segments size - 1.
        1 to: lines do: [:index | |x|
                x :=self extent x + ( )
                aCanvas line: self extent x+ (index*  to:  color: self defaultBorderColor