diff options
Diffstat (limited to 'activesupport/lib')
| -rw-r--r-- | activesupport/lib/active_support/core_ext/module.rb | 1 | ||||
| -rw-r--r-- | activesupport/lib/active_support/core_ext/module/attr_accessor_with_default.rb | 31 |
2 files changed, 32 insertions, 0 deletions
diff --git a/activesupport/lib/active_support/core_ext/module.rb b/activesupport/lib/active_support/core_ext/module.rb index 8d48de53dd..26c9bdf778 100644 --- a/activesupport/lib/active_support/core_ext/module.rb +++ b/activesupport/lib/active_support/core_ext/module.rb @@ -1,6 +1,7 @@ require File.dirname(__FILE__) + '/module/inclusion' require File.dirname(__FILE__) + '/module/attribute_accessors' require File.dirname(__FILE__) + '/module/attr_internal' +require File.dirname(__FILE__) + '/module/attr_accessor_with_default' require File.dirname(__FILE__) + '/module/delegation' require File.dirname(__FILE__) + '/module/introspection' require File.dirname(__FILE__) + '/module/loading' diff --git a/activesupport/lib/active_support/core_ext/module/attr_accessor_with_default.rb b/activesupport/lib/active_support/core_ext/module/attr_accessor_with_default.rb new file mode 100644 index 0000000000..31f14be344 --- /dev/null +++ b/activesupport/lib/active_support/core_ext/module/attr_accessor_with_default.rb @@ -0,0 +1,31 @@ +class Module + # Declare an attribute accessor with an initial default return value. + # + # To give attribute <tt>:age</tt> the initial value <tt>25</tt>: + # + # class Person + # attr_accessor_with_default :age, 25 + # end + # + # some_person.age + # => 25 + # some_person.age = 26 + # some_person.age + # => 26 + # + # To give attribute <tt>:element_name</tt> a dynamic default value, evaluated + # in scope of self: + # + # attr_accessor_with_default(:element_name) { name.underscore } + # + def attr_accessor_with_default(sym, default = nil, &block) + raise 'Default value or block required' unless default || block + define_method(sym, block_given? ? block : Proc.new { default }) + module_eval(<<-EVAL, __FILE__, __LINE__) + def #{sym}=(value) + class << self; attr_reader :#{sym} end + @#{sym} = value + end + EVAL + end +end |