Object

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Object

Methods

Included Modules

  • InstanceExecMethods

Public Class methods

lookup_missing_generator (class_id)

Lookup missing generators using const_missing. This allows any generator to reference another without having to know its location: RubyGems, ~/.rails/generators, and RAILS_ROOT/generators.

Public Instance methods

acts_like? (duck)

A duck-type assistant method. For example, Active Support extends Date to define an acts_like_date? method, and extends Time to define acts_like_time?. As a result, we can do "x.acts_like?(:time)" and "x.acts_like?(:date)" to do duck-type-safe comparisons, since classes that we want to act like Time simply need to define an acts_like_time? method.

blank? ()

An object is blank if it‘s false, empty, or a whitespace string. For example, "", " ", nil, [], and {} are blank.

This simplifies 

  if !address.nil? && !address.empty?

to 

  if !address.blank?

class_eval (*args, &block)

If class_eval is called on an object, add those methods to its metaclass

duplicable? ()

Can you safely .dup this object? False for nil, false, true, symbols, and numbers; true otherwise.

instance_exec (*args, &block)

Evaluate the block with the given arguments within the context of this object, so self is set to the method receiver.

From Mauricio‘s eigenclass.org/hiki/bounded+space+instance_exec

instance_variable_defined? (variable)

instance_variable_names ()

metaclass ()

Get object‘s meta (ghost, eigenclass, singleton) class

present? ()

An object is present if it‘s not blank.

returning (value) {|value| ...}

Returns value after yielding value to the block. This simplifies the process of constructing an object, performing work on the object, and then returning the object from a method. It is a Ruby-ized realization of the K combinator, courtesy of Mikael Brockman.

Examples

 # Without returning
 def foo
   values = []
   values << "bar"
   values << "baz"
   return values
 end

 foo # => ['bar', 'baz']

 # returning with a local variable
 def foo
   returning values = [] do
     values << 'bar'
     values << 'baz'
   end
 end

 foo # => ['bar', 'baz']

 # returning with a block argument
 def foo
   returning [] do |values|
     values << 'bar'
     values << 'baz'
   end
 end

 foo # => ['bar', 'baz']

to_json (options = {})

Dumps object in JSON (JavaScript Object Notation). See www.json.org for more info.

to_param ()

Alias of to_s.

to_param ()

to_query (key)

Converts an object into a string suitable for use as a URL query string, using the given key as the param name.

Note: This method is defined as a default implementation for all Objects for Hash#to_query to work.

try (method, *args, &block)

Tries to send the method only if object responds to it. Return nil otherwise. It will also forward any arguments and/or block like Object#send does.

Example :

# Without try @person ? @person.name : nil

With try @person.try(:name)

# try also accepts arguments/blocks for the method it is trying Person.try(:find, 1) @people.try(:map) {|p| p.name}

with_options (options) {|ActiveSupport::OptionMerger.new(self, options)| ...}

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. 

  with_options :order => 'created_at', :class_name => 'Comment' do |post|
    post.has_many :comments, :conditions => ['approved = ?', true], :dependent => :delete_all
    post.has_many :unapproved_comments, :conditions => ['approved = ?', false]
    post.has_many :all_comments
  end

Can also be used with an explicit receiver: 

  map.with_options :controller => "people" do |people|
    people.connect "/people",     :action => "index"
    people.connect "/people/:id", :action => "show"
  end