Build Status Gem Version MIT Licensed

This is a port of the parts of ActiveSupport that make sense for RubyMotion.

To see what's there, generate the documentation with the rdoc command from the repository root, or look into the lib folder. Almost everything is tested.


Install with

gem install motion-support

or add to your Gemfile

gem 'motion-support'

API docs

Are here.

Partial loading

It is also possible to only use parts of this library. To do so, change your Gemfile so that it reads:

gem 'motion-support', :require => false

Then add a require statement as shown below to your Rakefile.


require 'motion-support'

Loads everything.


require 'motion-support/callbacks'

Loads the MotionSupport::Callbacks module. It allows you to easily add Rails-style callbacks to any class.


require 'motion-support/concern'

Loads the MotionSupport::Concern module. This simplifies separating classes into modules and managing module dependencies.


require 'motion-support/inflector'

Loads the Inflector module and extensions to the String class. See the "Inflector" app in the examples/ folder for what the inflector can do.

Example usage include:

=> "AppDelegate"
=> HomeController
=> "things"
=> "mouse"


require 'motion-support/core_ext'

Loads all the extensions to core classes.


require 'motion-support/core_ext/array'

Loads extensions to class Array. Example usage include

%w( a b c d ).from(2)
=> ["c", "d"]
['one', 'two', 'three'].to_sentence
=> "one, two, and three"
[1, 2, 3, 4].in_groups_of(2)
=> [[1, 2], [3, 4]]

Extract options hash from variant args array

args = ['hello', 'world', { :foo => 'bar' }]
=> { :foo => 'bar' }


require 'motion-support/core_ext/class'

Loads extensions to class Class.

class Foo
  cattr_accessor :bar
  class_attribute :foo


require 'motion-support/core_ext/hash'

Loads extensions to class Hash, including class HashWithIndifferentAccess.

{ 'foo' => 'bar', 'baz' => 'bam' }.symbolize_keys
=> { :foo => 'bar', :baz => 'bam' }
{ 'foo' => 'bar', 'baz' => 'bam' }.except('foo')
=> { 'baz' => 'bam' }
{ 'foo' => 'bar', 'baz' => 'bam' }.with_indifferent_access
=> #<HashWithIndifferentAccess>


require 'motion-support/core_ext/integer'

Loads extensions to class Integer.

=> "1st"
=> "3rd"


require 'motion-support/core_ext/module'

Loads extensions to class Module.

module Mod
  mattr_accessor :foo, :bar
  attr_internal :baz
  delegate :boo, :to => :foo

  remove_method :baz


require 'motion-support/core_ext/numeric'

Loads extensions to class Numeric.

=> 10240
=> 2097152
=> 3


require 'motion-support/core_ext/object'

Loads extensions to class Object.

=> true
=> false
{ "hello" => "world", "foo" => "bar" }.to_query
=> "hello=world&foo=bar"
=> false
=> "1"
=> nil


require 'motion-support/core_ext/range'

Loads extensions to class Range.

=> true
=> true


require 'motion-support/core_ext/string'

Loads extensions to class String.

=> "RubyMotion"
=> "Users"
=> "mouse"
=> "foo/bar"
=> "app_delegate"
=> UIView


require 'motion-support/core_ext/time'

Loads extensions to class Time.


Differences to ActiveSupport

In general:

  • All I18n stuff was removed. Maybe it will be readded later.
  • No support for the TimeWithZone class (iOS apps don't need advanced time zone support)
  • No support for the DateTime class
  • All deprecated methods have been removed
  • All YAML extensions were removed, since RubyMotion doesn't come with YAML support
  • Kernel#silence_warnings and stream manipulation methods were removed
  • Multibyte string handling methods have been removed
  • All Rails-specific stuff was removed
  • The dependency resolution code was removed. So was the dynamic code reloading code
  • All marshalling code was removed
  • All logging code was removed
  • All extensions to Test::Unit were removed
  • The ActiveSupport namespace is called MotionSupport


  • Array#third .. Array#fourty_two were removed
  • Array#to_xml is missing
  • Array#to_sentence does not accept a :locale parameter
  • Class#subclasses is missing. It depends on ObjectSpace.each_object which is missing in RubyMotion
  • Hash#extractable_options? is missing
  • BigDecimal conversions were removed
  • Time.current an alias for
  • Date.current an alias for
  • Date#to_time does not accept a timezone form (:local, :utc)
  • Date#xmlschema is missing
  • String#parameterize is missing because it needs to transliterate the string, which is dependent on the locale
  • String#constantize is very slow. Cache the result if you use it.
  • String#to_time, #to_date, #to_datetime are missing because they depend on Date#_parse
  • String inquiry methods are missing
  • String multibyte methods are missing
  • String#html_safe and ERB extensions are not needed in RubyMotion
  • Range#to_s(:db) was removed
  • The rfc822 time format was removed, since it relies on time zone support.
  • Extensions to LoadError and NameError were removed
  • The ThreadSafe versions of Hash and Array are just aliases to the standard classes
  • In MotionSupport::Callbacks it is not possible to give a string containing Ruby code as a conditions via :if, since RubyMotion doesn't support eval.
  • In MotionSupport::Callbacks, if a proc is given as a condition to :if, the block must take the class instance as a parameter. self is not automatically set.
  • In MotionSupport::Callbacks#define_callbacks, the :terminator argument must take a block of the form lambda { |result| } where result is the intermediate result from the callback methods.
  • NumberHelper and numeric conversions only support phone numbers for now

Things to do / to decide:

  • RubyMotion lacks a Date class. in _stdlib there is a stub of a Date class that makes the Date extensions work. This stub needs to be completed.
  • Implement Object#to_xml
  • Implement Hash#from_xml
  • Do we need Hash#extractable_options??
  • Do we need Class#superclass_delegating_accessor?
  • Implement all InfiniteComparable extensions
  • Do we need File#atomic_write for thread-safe file writing?
  • Do we need Kernel#class_eval (it delegates to class_eval on this' singleton class)?
  • Do we need Module#qualified_const_defined?? What is that even for?
  • Do we need Module#synchronize?
  • Implement Numeric conversions, especially NumberHelper
  • Do we need Object#with_options?
  • Implement String#to_time, String#to_date. In the original ActiveSupport, they make use of the Date#_parse method (which seems like it's supposed to be private). Here, they should be implemented on top of Cocoa APIs
  • Do we need String#parameterize? If so, we need to find a way to transliterate UTF-8 characters.
  • Do we need the StringInquirer? It allows things like Rails.env.development? instead of Rails.env == 'development'
  • Do we need multibyte string handling extensions? AFAIK, all strings in RubyMotion are UTF-8. Is that true?
  • Do we need Struct#to_h?
  • Implement extensions to class Thread if they make sense.
  • Do we need the Configurable module?
  • Do we need the OrderedOptions class?
  • Some extensions have to be made available for Cocoa classes (NSArray, NSDictionary etc.), since we want to effectively handle return values from Objective-C methods (they return Cocoa classes). The way to do this is to write a conversion method from Cocoa class to Ruby class and delegate the extension methods in the Cocoa class to the conversion method. See motion/core_ext/ns_string.rb for an example.
  • Go through documentation and remove or rewrite things not relevant to RubyMotion, especially examples mentioning Rails components


ActiveSupport was originally written as part of Ruby on Rails by David Heinemeier Hansson. Over the years, countless contributors made many additions. They made this library possible.


Feel free to fork and submit pull requests!