Class: AttrExtras::AttrInitialize

Inherits:
Object
  • Object
show all
Defined in:
lib/attr_extras/params_builder.rb,
lib/attr_extras/attr_initialize.rb

Defined Under Namespace

Classes: ParamsBuilder

Instance Method Summary collapse

Constructor Details

#initialize(klass, names, block) ⇒ AttrInitialize

Returns a new instance of AttrInitialize.



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# File 'lib/attr_extras/attr_initialize.rb', line 4

def initialize(klass, names, block)
  @klass, @names, @block = klass, names, block
end

Instance Method Details

#apply ⇒ Object 



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# File 'lib/attr_extras/attr_initialize.rb', line 11

def apply
  # The define_method block can't call our methods, so we need to make
  # things available via local variables.
  block = @block

  klass_params = AttrExtras::AttrInitialize::ParamsBuilder.new(names)

  validate_arity = method(:validate_arity)
  validate_args = method(:validate_args)

  klass.send(:define_method, :initialize) do |*values|
    hash_values = (values[(klass_params.positional_args.length)..-1] || []).inject(:merge) || {}

    validate_arity.call(values.length, self.class)
    validate_args.call(values, klass_params)

    klass_params.default_values.each do |name, default_value|
      instance_variable_set("@#{name}", default_value)
    end

    klass_params.positional_args.zip(values).each do |name, value|
      instance_variable_set("@#{name}", value)
    end

    hash_values.each do |name, value|
      instance_variable_set("@#{name}", value)
    end

    if block
      instance_eval(&block)
    end
  end
end