I’ve been rebuilding the tool I use to manage the Burning Wheel Index (a project I really want to complete), which has reminded me of the user interface sweetspot that tools like readline can offer. I like to couple readline with a simple hand written recursive descent parser.

This sort of program occupy the area between a full GUI application, and simple command line tool. Compared to a full GUI application, the program is just much simpler to write. There are two wins over a simple command line program:

• Commandline argument parsing gets clumsy quickly. You have to route around what the shell wants to do. With readline you can drop into a real parser specifically designed for the task at hand.
• For long running tasks you don’t need to keep reiterating the command name.