method

attr_accessor_with_default

Ruby on Rails latest stable (v2.2.1) - 0 notes - Class: Module

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What's this?

attr_accessor_with_default(sym, default = nil, &block) public

Declare an attribute accessor with an initial default return value.

To give attribute :age the initial value 25:

  class Person
    attr_accessor_with_default :age, 25
  end

  some_person.age
  => 25
  some_person.age = 26
  some_person.age
  => 26

To give attribute :element_name a dynamic default value, evaluated in scope of self:

  attr_accessor_with_default(:element_name) { name.underscore }

Show source

# File activesupport/lib/active_support/core_ext/module/attr_accessor_with_default.rb, line 21
  def attr_accessor_with_default(sym, default = nil, &block)
    raise 'Default value or block required' unless !default.nil? || block
    define_method(sym, block_given? ? block : Proc.new { default })
    module_eval("def \#{sym}=(value)\nclass << self; attr_reader :\#{sym} end\n@\#{sym} = value\nend\n", __FILE__, __LINE__)
  end

attr_accessor_with_default

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