Wow this is good. My only complaint is annoyingly verbose yaml. What if I would like to use Kaitai instead of protobuffs, my .proto file is already a thousand lines, splitting each od these lines into 3-4 yaml indented lines is hurting readability
KS isn't for general data mangling, it's for "I have this format and I need a de novo parser for it that works under explicit rules" and you're willing to do the work of fully implementing it from the bytes up.