[ruby-core:112908] [Ruby master Feature#19520] Support for `Module.new(name)` and `Class.new(superclass, name)`.

15 Mar 2023

      Issue #19520 has been updated by fxn (Xavier Noria).

To be clear, Zeitwerk works only with constants. When you load `foo.rb`, the constant `:Foo` has to exist in `Object`, Zeitwerk does not care if the classes or modules went through an initial anonymous period. It also does not care if the file had a `Foo` constant reference or you did a `const_set` in the expected receiver. After loading, `Foo` has to exist. Otherwise, you get an exception.

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Feature #19520: Support for `Module.new(name)` and `Class.new(superclass, name)`.
https://bugs.ruby-lang.org/issues/19520#change-102425

* Author: ioquatix (Samuel Williams)
* Status: Open
* Priority: Normal
----------------------------------------
See <https://bugs.ruby-lang.org/issues/19450> for previous discussion and motivation.

[This proposal](https://github.com/ruby/ruby/pull/7376) introduces the `name` parameter to `Class.new` and `Module.new`:

```ruby
Class.new(superclass, name)
Module.new(name)
```

As a slight change, we could use keyword arguments instead.

## Example usage

The current Ruby test suite has code which shows the usefulness of this new method:

```ruby
  def labeled_module(name, &block)
    Module.new do
      singleton_class.class_eval {
        define_method(:to_s) {name}
        alias inspect to_s
        alias name to_s
      }
      class_eval(&block) if block
    end
  end
  module_function :labeled_module

  def labeled_class(name, superclass = Object, &block)
    Class.new(superclass) do
      singleton_class.class_eval {
        define_method(:to_s) {name}
        alias inspect to_s
        alias name to_s
      }
      class_eval(&block) if block
    end
  end
  module_function :labeled_class
```

The updated code would look like this:

```ruby
  def labeled_module(name, &block)
    Module.new(name, &block)
  end

  def labeled_class(name, superclass = Object, &block)
    Class.new(superclass, name, &block)
  end
  module_function :labeled_class
```

-- 
https://bugs.ruby-lang.org/