In practice, Ruby code isn’t. Once someone starts doing advanced meta programming, get the shovel, because you’re going to kill whoever wrote it and need to bury the body.
Rails largely gets away with this by having opinionated design, good documentation, and a large user base who have already written answers to your questions.
Metaprogramming in application code is one of those trends I'm glad is behind us. Might look cool and work great initially, but a painful refactor is near inevitable once there's been some turnover on the team and the problem space shifts in a way that invalidates the underlying assumptions.
Library code is another matter though.
Yes. And even just _finding_ relevant bits of code is difficult and painful, because you can't simply `grep` for the names of these metaprogrammed methods. They're simply not in the codebase.
This is why Elixir makes me hate life sometimes. They took a language like Erlang where it seemed almost impossible to write an unreadable program even when it was doing very sophisticated things, and Rubied it up.
At the end of the day coding is hard. I’d rather have nice DSLs to learn than verbose spaghetti to read.
Metaprogramming in a pull request at work? Nope. I'm going to smack some knuckles with a ruler. :)