Grant Rettke has an interesting take on abo-abo’s Hydra package. His
idea is that you can use hydras for a sort of lightweight literate
programming. Most Irreal readers are already aware of hydras’ utility
as a way of gathering related functionality into a menu-driven set of
keystrokes with a common prefix. Hydra functions can be configured to
easily repeat with a single keystroke rather than the longer complete
sequence needed on the first call.
Rettke uses hydras for all that, of course, but he also uses them when
learning a new package or set of related functions. Check out his post
to see how he uses a hydra as a sort of notebook to record what
functionality is available and what keystroke to use to call it. It
is, he says, executable documentation.