From: nathanielsullivan00@... Date: 2017-11-07T03:20:33+00:00 Subject: [ruby-core:83692] [Ruby trunk Feature#14079] Validate argument list without calling method Issue #14079 has been updated by nate00 (Nate Sullivan). Description updated I've removed the `String#prepend` example from the description. Thanks for catching that, Benoit and Hans. I agree with Benoit that an instance method on `Method`/`UnboundMethod` would be better than my `respond_to_arguments?` method. His proposal would work for instance methods, even if we haven't yet made an instance. ---------------------------------------- Feature #14079: Validate argument list without calling method https://bugs.ruby-lang.org/issues/14079#change-67716 * Author: nate00 (Nate Sullivan) * Status: Open * Priority: Normal * Assignee: * Target version: ---------------------------------------- I would find it useful to check whether a list of arguments matches a method signature, but without calling the method. I'd like to check the arguments list using a method called, for example, `respond_to_arguments?`. Here's an example: ~~~ruby class Foobar def self.baz(str) end end # Foobar.baz accepts 1 argument, not 0 or 2: Foobar.respond_to_arguments?(:baz, "one", "two") # => false Foobar.respond_to_arguments?(:baz, "one") # => true Foobar.respond_to_arguments?(:baz) # => false # Indeed, we get an ArgumentError if we pass 0 or 2 arguments: Foobar.baz("one", "two") # raises ArgumentError Foobar.baz("one") # success! Foobar.baz # raises ArgumentError ~~~ My use case is a background job processing system. It works like this: I call `MyWorker.perform_async` with some arguments; the arguments are serialized and put into a queue; and then a background worker takes those arguments from the queue, deserializes them and passes them to `MyWorker.perform`. If I passed invalid arguments, I don't know they were invalid until the background worker tries to call `perform`. But I'd like to know immediately when I call `perform_async`. Perhaps a `respond_to_arguments_missing?` method would be required also. Maybe `respond_to_arguments?` is a bad name. You could reasonably assume that it takes the same optional second parameter as `respond_to?` (i.e., `include_all`), but my proposal doesn't support an optional second parameter. Thank you for your consideration! -- https://bugs.ruby-lang.org/ Unsubscribe: