MCAP Indexing — Monday Morning Haskell (opens in new tab)

In the first 4 parts of this series (Part 1, Part 2, Part 3, Part 4), we’ve written a program that can parse specific topic information out of MCAP-based ROS2 bags. The Megaparsec library helped us a lot, but our current approach has a weakness; our program scans through the entire file sequentially. Bag files can be very large! So if we’re only interested in a few topics, it can be wasteful to parse through everything.