Parent

Included Modules

Hashie::Dash

A Dash is a 'defined' or 'discrete' Hash, that is, a Hash that has a set of defined keys that are accessible (with optional defaults) and only those keys may be set or read.

Dashes are useful when you need to create a very simple lightweight data object that needs even fewer options and resources than something like a DataMapper resource.

It is preferrable to a Struct because of the in-class API for defining properties as well as per-property defaults.

Attributes

defaults[R]
properties[R]
required_properties[R]

Public Class Methods

inherited(klass) click to toggle source
# File lib/hashie/dash.rb, line 67
def self.inherited(klass)
  super
  (@subclasses ||= Set.new) << klass
  klass.instance_variable_set('@properties', self.properties.dup)
  klass.instance_variable_set('@defaults', self.defaults.dup)
  klass.instance_variable_set('@required_properties', self.required_properties.dup)
end
new(attributes = {}, &block) click to toggle source

You may initialize a Dash with an attributes hash just like you would many other kinds of data objects.

# File lib/hashie/dash.rb, line 89
def initialize(attributes = {}, &block)
  super(&block)

  self.class.defaults.each_pair do |prop, value|
    self[prop] = value
  end

  attributes.each_pair do |att, value|
    self[att] = value
  end if attributes
  assert_required_properties_set!
end
property(property_name, options = {}) click to toggle source

Defines a property on the Dash. Options are as follows:

  • :default - Specify a default value for this property, to be returned before a value is set on the property in a new Dash.

  • :required - Specify the value as required for this property, to raise an error if a value is unset in a new or existing Dash.

# File lib/hashie/dash.rb, line 30
def self.property(property_name, options = {})
  property_name = property_name.to_sym

  self.properties << property_name

  if options.has_key?(:default)
    self.defaults[property_name] = options[:default]
  elsif self.defaults.has_key?(property_name)
    self.defaults.delete property_name
  end

  unless instance_methods.map { |m| m.to_s }.include?("#{property_name}=")
    class_eval           def #{property_name}(&block)            self.[](#{property_name.to_s.inspect}, &block)          end          def #{property_name}=(value)            self.[]=(#{property_name.to_s.inspect}, value)          end
  end

  if defined? @subclasses
    @subclasses.each { |klass| klass.property(property_name, options) }
  end
  required_properties << property_name if options.delete(:required)
end
property?(name) click to toggle source

Check to see if the specified property has already been defined.

# File lib/hashie/dash.rb, line 77
def self.property?(name)
  properties.include? name.to_sym
end
required?(name) click to toggle source

Check to see if the specified property is required.

# File lib/hashie/dash.rb, line 83
def self.required?(name)
  required_properties.include? name.to_sym
end

Public Instance Methods

[](property) click to toggle source

Retrieve a value from the Dash (will return the property's default value if it hasn't been set).

# File lib/hashie/dash.rb, line 108
def [](property)
  assert_property_exists! property
  value = super(property.to_s)
  yield value if block_given?
  value
end
Also aliased as: _regular_reader
[]=(property, value) click to toggle source

Set a value on the Dash in a Hash-like way. Only works on pre-existing properties.

# File lib/hashie/dash.rb, line 117
def []=(property, value)
  assert_property_required! property, value
  assert_property_exists! property
  super(property.to_s, value)
end
Also aliased as: _regular_writer
_regular_reader(property) click to toggle source
Alias for: []
_regular_writer(property, value) click to toggle source
Alias for: []=

[Validate]

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