You can edit BASIC code on the fly while testing and then go back to the source and make the changes. Anyone who has developed BASIC programs more than a few dozen lines long will tell you that the only productive way to develop and maintain the code is to use a tool like Basikit that allows you to write programs with labels rather than line numbers. Basikit also has an interactive mode that helps you make in-line changes and logs them to a file so you can keep track of the changes you need to make to your source file.