Feature #19521
Updated by ioquatix (Samuel Williams) about 1 year ago
See https://bugs.ruby-lang.org/issues/19450 for previous discussion and motivation.
This proposal introduces `Module#name=` (and thus also `Class#name`) to set the temporary class name. The name assignment has no effect if the module/class already has a permanent name.
```ruby
c = Class.new do
self.name = "fake name"
end
c = Class.new
c.name = "fake name"
```
Alternatively, we could use `set_name`:
```ruby
Class.new do
set_name "fake_name"
end
```
I believe once the name is set, it is impossible to change, but I'll check the implementation.
## 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 do
self.name = name
class_eval(&block) if block
end
end
def labeled_class(name, superclass = Object, &block)
Class.new(superclass) do
self.name = name
class_eval(&block) if block
end
end
module_function :labeled_class
```
Because the name cannot be set as part of `.new`, we have to have a separate block to set the name, before calling `class_eval`. I think the ergonomics and performance of this are slightly worse than the [counter proposal](https://bugs.ruby-lang.org/issues/19520).