module T::Private::Abstract::Data
We need to associate data with abstract modules. We could add instance methods to them that access ivars, but those methods will unnecessarily pollute the module namespace, and they'd have access to other private state and methods that they don't actually need. We also need to associate data with arbitrary classes/modules that implement abstract mixins, where we don't control the interface at all. So, we access data via these `get` and `set` methods.
Using instance_variable_get/set here is gross, but the alternative is to use a hash keyed on `mod`, and we can't trust that arbitrary modules can be added to those, because there are lurky modules that override the `hash` method with something completely broken.
Public Class Methods
# File lib/types/private/abstract/data.rb, line 14 def self.get(mod, key) mod.instance_variable_get("@opus_abstract__#{key}") end
# File lib/types/private/abstract/data.rb, line 22 def self.key?(mod, key) mod.instance_variable_defined?("@opus_abstract__#{key}") end
# File lib/types/private/abstract/data.rb, line 18 def self.set(mod, key, value) mod.instance_variable_set("@opus_abstract__#{key}", value) end
Works like `setdefault` in Python. If key has already been set, return its value. If not, insert `key` with a value of `default` and return `default`.
# File lib/types/private/abstract/data.rb, line 28 def self.set_default(mod, key, default) if self.key?(mod, key) self.get(mod, key) else self.set(mod, key, default) default end end