My original hope was actually to instance_eval the gemfile, which is what bundler does, but with my own handler to capture the information for the sort. But I decided that would be harder, especially for managing comments.

By far the goofiest code in the existing gem is the code that pulls a `group` or `source` from an inline gem so it can normalize it with blocks — that would probably have been easier with instance_eval, because Ruby would have parsed it.