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