The document discusses porting the readline library to Ruby. It proposes either extending readline with Ruby or building a new readline-like library in Ruby called ReadRhine. ReadRhine uses an MVC architecture with separate models, views, and controls. It aims to have a unit test friendly design with spec files for components like the buffer and completion. The document outlines available commands and how to define keys in an internal DSL. It also lists some TODO items like improving completion and handling signals safely.