Writing code in QLingo for XMPie uStore in InDesign is challenging since it can be difficult to read due to the font and lack of colours to highlight key areas. I prefer to write code outside of InDesign so that I can save it in an easy to reference format.
My programming editor of choice and editor for general usage is Notepad++. It supports multiple programming languages and gives the option of adding your own custom language. I created a QLingo language addon that you can download from the following link: QLingo for Notepad++.
Comments in your code are deleted when you import into your InDesign document, but its useful to keep in your saved source code for when your debugging it 3 months from now.