AsReadonly

Expose your collections as readonly objects without fear.

Example

  ara = AsReadonly::Array.new([1,2])
  ara[0]    # => 1
  ara.clear # raises NoMethodError

Installation

Add this line to your application's Gemfile:

gem 'as_readonly'

And then execute:

$ bundle

Or install it yourself as:

$ gem install as_readonly

Require

• as_readonly/array

    AsReadonly::Array
  

• as_readonly/hash

    AsReadonly::Hash
  

• as_readonly/set

    AsReadonly::Set
  

• as_readonly/collections

    as_readonly/array
    as_readonly/hash
    as_readonly/set`
  

• as_readonly/core_ext/array

    array.as_readonly # => AsReadonly::Array.new(array)
  

• as_readonly/core_ext/hash

    hash.as_readonly  # => AsReadonly::Hash.new(hash)
  

• as_readonly/core_ext/set

    set.as_readonly   # => AsReadonly::Set.new(set)
  

• as_readonly/core_ext/collections

    as_readonly/core_ext/array
    as_readonly/core_ext/hash
    as_readonly/core_ext/set
  

• as_readonly/core_ext/module

    Module#attr_readonly
  
    class MyClass
      attr_readonly :array
      def initialize
        @array = []
      end
    end
  
    MyClass.new.array.size  # => 0
    MyClass.new.array.clear # => NoMethodError exception
  

• as_readonly/core_ext/all

    as_readonly/core_ext/collections
    as_readonly/core_ext/module
  

• as_readonly - everything above

Usage

require 'as_readonly/array'

class MyClass
  def initialize
    @collection = []
  end

  def collection
    @read_collection ||= AsReadonly::Array.new(@collection)
  end
end

Note

This gem does not prevent calling mutating methods on collection elements. Obviously.

class MyClass
  def initialize
    @collection = ["asd"]
  end

  def collection
    @read_collection ||= AsReadonly::Array.new(@collection)
  end
end

c = MyClass.new
c.collection[0].upcase

Inspirations

• http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/144294
• http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/144375
• http://msdn.microsoft.com/en-us/library/e78dcd75.aspx

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Added some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request