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require 'active_support/option_merger'
class Object
# An elegant way to factor duplication out of options passed to a series of
# method calls. Each method called in the block, with the block variable as
# the receiver, will have its options merged with the default +options+ hash
# provided. Each method called on the block variable must take an options
# hash as its final argument.
#
# Without <tt>with_options></tt>, this code contains duplication:
#
# class Account < ActiveRecord::Base
# has_many :customers, dependent: :destroy
# has_many :products, dependent: :destroy
# has_many :invoices, dependent: :destroy
# has_many :expenses, dependent: :destroy
# end
#
# Using <tt>with_options</tt>, we can remove the duplication:
#
# class Account < ActiveRecord::Base
# with_options dependent: :destroy do |assoc|
# assoc.has_many :customers
# assoc.has_many :products
# assoc.has_many :invoices
# assoc.has_many :expenses
# end
# end
#
# It can also be used with an explicit receiver:
#
# I18n.with_options locale: user.locale, scope: 'newsletter' do |i18n|
# subject i18n.t :subject
# body i18n.t :body, user_name: user.name
# end
#
# When you don't pass an explicit receiver, it executes the whole block
# in merging options context:
#
# class Account < ActiveRecord::Base
# with_options dependent: :destroy do
# has_many :customers
# has_many :products
# has_many :invoices
# has_many :expenses
# end
# end
#
# <tt>with_options</tt> can also be nested since the call is forwarded to its receiver.
# Each nesting level will merge inherited defaults in addition to their own.
def with_options(options, &block)
option_merger = ActiveSupport::OptionMerger.new(self, options)
block.arity.zero? ? option_merger.instance_eval(&block) : block.call(option_merger)
end
end
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