Making my text editor save the work

[Kevin J]

I was looking at the docs on how to make my program save the work that
the user is doing. I can get it to say to a file that the program it
self tells it to, so what I have is:
put field"txtWindow" into URL "file:C:\Program Files\Revolution
2.5.1\Viper Editor\test.py"

How do I make it so that when the user clicks save as they can name
the file they want to save it as?

Thanks

Kevin