2 # Returns +value+ after yielding +value+ to the block. This simplifies the
3 # process of constructing an object, performing work on the object, and then
4 # returning the object from a method. It is a Ruby-ized realization of the K
5 # combinator, courtesy of Mikael Brockman.
17 # foo # => ['bar', 'baz']
19 # # returning with a local variable
21 # returning values = [] do
27 # foo # => ['bar', 'baz']
29 # # returning with a block argument
31 # returning [] do |values|
37 # foo # => ['bar', 'baz']
43 # Yields <code>x</code> to the block, and then returns <code>x</code>.
44 # The primary purpose of this method is to "tap into" a method chain,
45 # in order to perform operations on intermediate results within the chain.
47 # (1..10).tap { |x| puts "original: #{x.inspect}" }.to_a.
48 # tap { |x| puts "array: #{x.inspect}" }.
49 # select { |x| x%2 == 0 }.
50 # tap { |x| puts "evens: #{x.inspect}" }.
52 # tap { |x| puts "squares: #{x.inspect}" }
56 end unless Object
.respond_to
?(:tap)
58 # An elegant way to factor duplication out of options passed to a series of
59 # method calls. Each method called in the block, with the block variable as
60 # the receiver, will have its options merged with the default +options+ hash
61 # provided. Each method called on the block variable must take an options
62 # hash as its final argument.
64 # with_options :order => 'created_at', :class_name => 'Comment' do |post|
65 # post.has_many :comments, :conditions => ['approved = ?', true], :dependent => :delete_all
66 # post.has_many :unapproved_comments, :conditions => ['approved = ?', false]
67 # post.has_many :all_comments
70 # Can also be used with an explicit receiver:
72 # map.with_options :controller => "people" do |people|
73 # people.connect "/people", :action => "index"
74 # people.connect "/people/:id", :action => "show"
77 def with_options(options
)
78 yield ActiveSupport
::OptionMerger.new(self, options
)
81 # A duck-type assistant method. For example, Active Support extends Date
82 # to define an acts_like_date? method, and extends Time to define
83 # acts_like_time?. As a result, we can do "x.acts_like?(:time)" and
84 # "x.acts_like?(:date)" to do duck-type-safe comparisons, since classes that
85 # we want to act like Time simply need to define an acts_like_time? method.
87 respond_to
? "acts_like_#{duck}?"