Class: Module
- Inherits:
-
Object
- Object
- Module
- Defined in:
- lib/aliasing.rb,
lib/attribute_accessors.rb
Overview
:nodoc:
Instance Method Summary collapse
-
#alias_attribute(new_name, old_name) ⇒ Object
Allows you to make aliases for attributes, which includes getter, setter, and query methods.
-
#alias_method_chain(target, feature) {|aliased_target, punctuation| ... } ⇒ Object
Encapsulates the common pattern of:.
- #mattr_accessor(*syms) ⇒ Object
- #mattr_reader(*syms) ⇒ Object
- #mattr_writer(*syms) ⇒ Object
Instance Method Details
#alias_attribute(new_name, old_name) ⇒ 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 < ActiveRecord::Base
alias_attribute :subject, :title
end
e = Email.find(1)
e.title # => "Superstars"
e.subject # => "Superstars"
e.subject? # => true
e.subject = "Megastars"
e.title # => "Megastars"
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# File 'lib/aliasing.rb', line 81 def alias_attribute(new_name, old_name) module_eval <<-STR, __FILE__, __LINE__+1 def #{new_name}; #{old_name}; end def #{new_name}?; #{old_name}?; end def #{new_name}=(v); self.#{old_name} = v; end STR end |
#alias_method_chain(target, feature) {|aliased_target, punctuation| ... } ⇒ Object
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.
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# File 'lib/aliasing.rb', line 53 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? alias_method "#{aliased_target}_without_#{feature}#{punctuation}", target alias_method target, "#{aliased_target}_with_#{feature}#{punctuation}" end |
#mattr_accessor(*syms) ⇒ Object
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# File 'lib/attribute_accessors.rb', line 75 def mattr_accessor(*syms) mattr_reader(*syms) mattr_writer(*syms) end |
#mattr_reader(*syms) ⇒ Object
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# File 'lib/attribute_accessors.rb', line 35 def mattr_reader(*syms) syms.each do |sym| next if sym.is_a?(Hash) class_eval(<<-EOS, __FILE__, __LINE__) unless defined? @@#{sym} @@#{sym} = nil end def self.#{sym} @@#{sym} end def #{sym} @@#{sym} end EOS end end |
#mattr_writer(*syms) ⇒ Object
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# File 'lib/attribute_accessors.rb', line 54 def mattr_writer(*syms) = syms.last.is_a?(Hash) ? syms.pop : {} syms.each do |sym| class_eval(<<-EOS, __FILE__, __LINE__) unless defined? @@#{sym} @@#{sym} = nil end def self.#{sym}=(obj) @@#{sym} = obj end #{" def #{sym}=(obj) @@#{sym} = obj end " unless [:instance_writer] == false } EOS end end |