Module: T::Private::Abstract::Data

Defined in:

lib/types/private/abstract/data.rb

Overview

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.

Class Method Summary

• .get(mod, key) ⇒ Object
• .key?(mod, key) ⇒ Boolean
• .set(mod, key, value) ⇒ Object
• .set_default(mod, key, default) ⇒ Object

  Works like ‘setdefault` in Python.

Class Method Details

.get(mod, key) ⇒ Object

# File 'lib/types/private/abstract/data.rb', line 14

def self.get(mod, key)
  mod.instance_variable_get("@opus_abstract__#{key}") if key?(mod, key)
end

.key?(mod, key) ⇒ Boolean

Returns:

• (Boolean)

# File 'lib/types/private/abstract/data.rb', line 22

def self.key?(mod, key)
  mod.instance_variable_defined?("@opus_abstract__#{key}")
end

.set(mod, key, value) ⇒ Object

# File 'lib/types/private/abstract/data.rb', line 18

def self.set(mod, key, value)
  mod.instance_variable_set("@opus_abstract__#{key}", value)
end

.set_default(mod, key, default) ⇒ Object

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