Solutions for Advent of Code, a series of programming puzzles released in December every year.

• Solution DSL: provides a way to write down solutions, verify them against test cases, and derive the answer from the real input, all without explicit boilerplate code
• Downloading: automatically downloads puzzle inputs from the website to /input/[YYYY]/day[DD].txt, provided /.session_token exists
• Submission: automatically submits the answer for the last successful solve to the website, provided /.session_token exists
• Login: Retrieves or refreshes /.session_token with OAuth as necessary