
Issue #21160 has been updated by nobu (Nobuyoshi Nakada). Why not rescue `LocalJumpError`? ```ruby def self.fulfill_promise(promise_name, data) puts "Fulfilling promise: #{promise_name}" callback = @@promise_callbacks[promise_name] begin complete = callback.call(data) rescue LocalJumpError => e complete = e.exit_value end if complete puts 'Complete!' else puts 'Failed!' end end ``` This works with both of `return` and `break` in already released versions of Ruby, and even your DSL does not need to change. If we were add a new keyword, you would have to wait for the end of this year at least. ---------------------------------------- Feature #21160: Local return from proc https://bugs.ruby-lang.org/issues/21160#change-112123 * Author: JustJosh (Joshua Stowers) * Status: Open ---------------------------------------- When writing DSL-style helper methods, I often store block arguments as procs to use as callbacks. Using `return` in a proc will return from the context it was created in, which is unsuitable in the following example. Since procs cannot be converted to lambdas, I end up using `next` to return a value from them early. Example: ``` ruby fulfills_promise :generate_large_image do |image_data| next false if image_data.nil? puts 'Saving image..' # etc. end ``` This works but confuses most readers. I propose introducing an alias for it that is more appropriate for this use case. Perhaps `pass` or `continue`? It's worth noting that `return` would work with `fulfills_promise :foo, -> (bar) do`, though it detracts a bit from a DSL's expressiveness. -- https://bugs.ruby-lang.org/