Dynamically register handlers

[sambostock]

Motivation

This PR offers a proof-of-concept of dynamically registering handlers by discovering their public methods which conform to the handler name pattern. This is a similar approach to that used by other tools such as Minitest (discovering public test_* methods) or Rails generators (executing public methods in the order they are defined).

This approach was conceived while discussing the RubyLsp/UseRegisterWithHandlerMethod cop, which checks that all methods conforming to the handler name pattern are registered in initialize, and that all registered handlers have a corresponding method definition. This approach would make the cop obsolete.

Implementation

As a proof-of-concept, this prepends a module into Prism::Dispatcher to support dynamically determining the event list to handle. However, the proposal would be to upstream the following directly into Prism:

module Prism
  class Dispatcher
    def register(listener, *events)
      events = listener.public_methods.grep(/^on_.+_(?:enter|leave)$/) if events.empty?

      # ...existing code...
    end

Automated Tests

Manual Tests

[graphite-app]

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