Show HN: A tool to auto-generate vocabulary for a book

Takes a book in English, finds the words that are "rare" (by the measure IDF >= 15 or -ln(frequency) > 14) and lists the definition in a dictionary and the places it occurs in the original text. The final output is a static HTML file. You can view a live demo for a subset of words from a book here: https://deedy.github.io/vocabuliwala/

Some examples output demonstrating some of the key features of Vocabuliwala: - Dictionary lookup - Secondary dictionary lookup: looking up dictionary meanings which themselves need explanation - Difficulty rating - Show appearances in the input book

Who is this for? - A casual reader of a book - A teacher trying to teach a book - Students trying to learn vocabulary for a standardized test

Curious to get the community's feedback and see how I can improve this!