Class | Module |
In: |
lib/inactive_support/core_ext/module/aliasing.rb
|
Parent: | Object |
Allows you to make aliases for attributes, which includes getter, setter, and query methods.
Example:
class Content < ActiveRecord::Base # has a title attribute end class Email < Content alias_attribute :subject, :title end e = Email.find(1) e.title # => "Superstars" e.subject # => "Superstars" e.subject? # => true e.subject = "Megastars" e.title # => "Megastars"
# File lib/inactive_support/core_ext/module/aliasing.rb, line 63 def alias_attribute(new_name, old_name) module_eval "def \#{new_name}; self.\#{old_name}; end\ndef \#{new_name}?; self.\#{old_name}?; end\ndef \#{new_name}=(v); self.\#{old_name} = v; end\n", __FILE__, __LINE__+1 end
Encapsulates the common pattern of:
alias_method :foo_without_feature, :foo alias_method :foo, :foo_with_feature
With this, you simply do:
alias_method_chain :foo, :feature
And both aliases are set up for you.
Query and bang methods (foo?, foo!) keep the same punctuation:
alias_method_chain :foo?, :feature
is equivalent to
alias_method :foo_without_feature?, :foo? alias_method :foo?, :foo_with_feature?
so you can safely chain foo, foo?, and foo! with the same feature.
# File lib/inactive_support/core_ext/module/aliasing.rb, line 23 def alias_method_chain(target, feature) # Strip out punctuation on predicates or bang methods since # e.g. target?_without_feature is not a valid method name. aliased_target, punctuation = target.to_s.sub(/([?!=])$/, ''), $1 yield(aliased_target, punctuation) if block_given? with_method, without_method = "#{aliased_target}_with_#{feature}#{punctuation}", "#{aliased_target}_without_#{feature}#{punctuation}" alias_method without_method, target alias_method target, with_method case when public_method_defined?(without_method) public target when protected_method_defined?(without_method) protected target when private_method_defined?(without_method) private target end end