Loading collection data...
Collections are a way for you to organize kata so that you can create your own training routines. Every collection you create is public and automatically sharable with other warriors. After you have added a few kata to a collection you and others can train on the kata contained within the collection.
Get started now by creating a new collection.
ecase raises an error if none of the test cases are satisfied. Writing the function like this just ensures it will fail loudly if it is called with an input other than one of the characters #\R or #\L. It's not very important here but this sort of thing could help detect a bug (your function is being called with an unexpected input) in a large application.
Why is that best practice if in case of no #\R we still check if it is #\L