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Class: OpenStruct

Relationships & Source Files
Inherits: Object
Defined in: lib/ostruct.rb,
lib/ostruct/version.rb

Constant Summary

Class Method Summary

Instance Attribute Summary

  • #table! readonly

    Alias for #table.

  • #table (also: #table!) readonly protected Internal use only
  • #modifiable? ⇒ Boolean readonly private Internal use only

    Used internally to check if the OpenStruct is able to be modified before granting access to the internal Hash table to be modified.

Instance Method Summary

Constructor Details

.new(hash = nil) ⇒ OpenStruct

Creates a new OpenStruct object. By default, the resulting OpenStruct object will have no attributes.

The optional #hash, if given, will generate attributes and values (can be a Hash, an OpenStruct or a Struct). For example:

require "ostruct"
hash = { "country" => "Australia", :capital => "Canberra" }
data = OpenStruct.new(hash)

data   # => #<OpenStruct country="Australia", capital="Canberra">
[ GitHub ]

  
# File 'lib/ostruct.rb', line 94

def initialize(hash=nil)
  @table = {}
  if hash
    hash.each_pair do |k, v|
      k = k.to_sym
      @table[k] = v
    end
  end
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(mid, *args)

This method is for internal use only.
[ GitHub ]

  
# File 'lib/ostruct.rb', line 207

def method_missing(mid, *args) # :nodoc:
  len = args.length
  if mname = mid[/.*(?==\z)/m]
    if len != 1
      raise ArgumentError, "wrong number of arguments (given #{len}, expected 1)", caller(1)
    end
    modifiable?[new_ostruct_member!(mname)] = args[0]
  elsif len == 0 # and /\A[a-z_]\w*\z/ =~ mid #
    if @table.key?(mid)
      new_ostruct_member!(mid) unless frozen?
      @table[mid]
    end
  elsif @table.key?(mid)
    raise ArgumentError, "wrong number of arguments (given #{len}, expected 0)"
  else
    begin
      super
    rescue NoMethodError => err
      err.backtrace.shift
      raise
    end
  end
end

Instance Attribute Details

#modifiable?Boolean (readonly, private)

This method is for internal use only.

Used internally to check if the OpenStruct is able to be modified before granting access to the internal Hash table to be modified.

[ GitHub ]

  
# File 'lib/ostruct.rb', line 171

def modifiable? # :nodoc:
  begin
    @modifiable = true
  rescue
    exception_class = defined?(FrozenError) ? FrozenError : RuntimeError
    raise exception_class, "can't modify frozen #{self.class}", caller(3)
  end
  @table
end

#table (readonly, protected) Also known as: #table!

This method is for internal use only.
[ GitHub ]

  
# File 'lib/ostruct.rb', line 339

attr_reader :table # :nodoc:

#table! (readonly)

Alias for #table.

[ GitHub ]

  
# File 'lib/ostruct.rb', line 341

alias table! table

Instance Method Details

#==(other)

Compares this object and other for equality. An OpenStruct is equal to other when other is an OpenStruct and the two objects’ Hash tables are equal.

require "ostruct"
first_pet  = OpenStruct.new("name" => "Rowdy")
second_pet = OpenStruct.new(:name  => "Rowdy")
third_pet  = OpenStruct.new("name" => "Rowdy", :age => nil)

first_pet == second_pet   # => true
first_pet == third_pet    # => false
[ GitHub ]

  
# File 'lib/ostruct.rb', line 356

def ==(other)
  return false unless other.kind_of?(OpenStruct)
  @table == other.table!
end

#[](name) ⇒ Object

Returns the value of an attribute.

require "ostruct"
person = OpenStruct.new("name" => "John Smith", "age" => 70)
person[:age]   # => 70, same as person.age
[ GitHub ]

  
# File 'lib/ostruct.rb', line 241

def [](name)
  @table[name.to_sym]
end

#[]=(name, obj) ⇒ Object

Sets the value of an attribute.

require "ostruct"
person = OpenStruct.new("name" => "John Smith", "age" => 70)
person[:age] = 42   # equivalent to person.age = 42
person.age          # => 42
[ GitHub ]

  
# File 'lib/ostruct.rb', line 256

def []=(name, value)
  modifiable?[new_ostruct_member!(name)] = value
end

#delete_field(name)

Removes the named field from the object. Returns the value that the field contained if it was defined.

require "ostruct"

person = OpenStruct.new(name: "John", age: 70, pension: 300)

person.delete_field("age")   # => 70
person                       # => #<OpenStruct name="John", pension=300>

Setting the value to nil will not remove the attribute:

person.pension = nil
person                 # => #<OpenStruct name="John", pension=nil>
[ GitHub ]

  
# File 'lib/ostruct.rb', line 305

def delete_field(name)
  sym = name.to_sym
  begin
    singleton_class.remove_method(sym, "#{sym}=")
  rescue NameError
  end
  @table.delete(sym) do
    raise NameError.new("no field `#{sym}' in #{self}", sym)
  end
end

#dig(name, ...) ⇒ Object

Extracts the nested value specified by the sequence of name objects by calling dig at each step, returning nil if any intermediate step is nil.

require "ostruct"
address = OpenStruct.new("city" => "Anytown NC", "zip" => 12345)
person  = OpenStruct.new("name" => "John Smith", "address" => address)

person.dig(:address, "zip")            # => 12345
person.dig(:business_address, "zip")   # => nil

data = OpenStruct.new(:array => [1, [2, 3]])

data.dig(:array, 1, 0)   # => 2
data.dig(:array, 0, 0)   # TypeError: Integer does not have #dig method
[ GitHub ]

  
# File 'lib/ostruct.rb', line 280

def dig(name, *names)
  begin
    name = name.to_sym
  rescue NoMethodError
    raise TypeError, "#{name} is not a symbol nor a string"
  end
  @table.dig(name, *names)
end

#each_pair {|name, value| ... } ⇒ ostruct #each_pairEnumerator

Yields all attributes (as symbols) along with the corresponding values or returns an enumerator if no block is given.

require "ostruct"
data = OpenStruct.new("country" => "Australia", :capital => "Canberra")
data.each_pair.to_a   # => [[:country, "Australia"], [:capital, "Canberra"]]
[ GitHub ]

  
# File 'lib/ostruct.rb', line 147

def each_pair
  return to_enum(__method__) { @table.size } unless block_given?
  @table.each_pair{|p| yield p}
  self
end

#eql?(other) ⇒ Boolean

Compares this object and other for equality. An OpenStruct is eql? to other when other is an OpenStruct and the two objects’ Hash tables are eql?.

[ GitHub ]

  
# File 'lib/ostruct.rb', line 366

def eql?(other)
  return false unless other.kind_of?(OpenStruct)
  @table.eql?(other.table!)
end

#freeze

[ GitHub ]

  
# File 'lib/ostruct.rb', line 197

def freeze
  @table.each_key {|key| new_ostruct_member!(key)}
  super
end

#hash

Computes a hash code for this OpenStruct. Two OpenStruct objects with the same content will have the same hash code (and will compare using #eql?).

See also Object#hash.

[ GitHub ]

  
# File 'lib/ostruct.rb', line 376

def hash
  @table.hash
end

#initialize_copy(orig)

This method is for internal use only.

Duplicates an OpenStruct object’s Hash table.

[ GitHub ]

  
# File 'lib/ostruct.rb', line 105

def initialize_copy(orig) # :nodoc:
  super
  @table = @table.dup
end

#inspect Also known as: #to_s

Returns a string containing a detailed summary of the keys and values.

[ GitHub ]

  
# File 'lib/ostruct.rb', line 321

def inspect
  ids = (Thread.current[InspectKey] ||= [])
  if ids.include?(object_id)
    detail = ' ...'
  else
    ids << object_id
    begin
      detail = @table.map do |key, value|
        " #{key}=#{value.inspect}"
      end.join(',')
    ensure
      ids.pop
    end
  end
  ['#<', self.class, detail, '>'].join
end

#marshal_dump

Provides marshalling support for use by the Marshal library.

[ GitHub ]

  
# File 'lib/ostruct.rb', line 156

def marshal_dump
  @table
end

#marshal_load(x)

Provides marshalling support for use by the Marshal library.

[ GitHub ]

  
# File 'lib/ostruct.rb', line 163

def marshal_load(x)
  @table = x
end

#new_ostruct_member!(name) (private)

This method is for internal use only.

Used internally to defined properties on the OpenStruct. It does this by using the metaprogramming function define_singleton_method for both the getter method and the setter method.

[ GitHub ]

  
# File 'lib/ostruct.rb', line 187

def new_ostruct_member!(name) # :nodoc:
  name = name.to_sym
  unless singleton_class.method_defined?(name)
    define_singleton_method(name) { @table[name] }
    define_singleton_method("#{name}=") {|x| modifiable?[name] = x}
  end
  name
end

#respond_to_missing?(mid, include_private = false) ⇒ Boolean

This method is for internal use only.
[ GitHub ]

  
# File 'lib/ostruct.rb', line 202

def respond_to_missing?(mid, include_private = false) # :nodoc:
  mname = mid.to_s.chomp("=").to_sym
  defined?(@table) && @table.key?(mname) || super
end

#to_hHash #to_h {|name, value| ... } ⇒ Hash

Converts the OpenStruct to a hash with keys representing each attribute (as symbols) and their corresponding values.

If a block is given, the results of the block on each pair of the receiver will be used as pairs.

require "ostruct"
data = OpenStruct.new("country" => "Australia", :capital => "Canberra")
data.to_h   # => {:country => "Australia", :capital => "Canberra" }
data.to_h {|name, value| [name.to_s, value.upcase] }
            # => {"country" => "AUSTRALIA", "capital" => "CANBERRA" }
[ GitHub ]

  
# File 'lib/ostruct.rb', line 127

def to_h(&block)
  if block_given?
    @table.to_h(&block)
  else
    @table.dup
  end
end

#to_s

Alias for #inspect.

[ GitHub ]

  
# File 'lib/ostruct.rb', line 337

alias :to_s :inspect