Module: CstyleEnum

Included in:
Module
Defined in:
lib/cstyle_enum.rb,
lib/cstyle_enum/version.rb

Constant Summary collapse

VERSION = 
"0.1.0"

Instance Method Summary collapse

Instance Method Details

#enum(step = 1, &block) ⇒ Object Also known as: cstyle_enum 



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# File 'lib/cstyle_enum.rb', line 4

def enum step = 1, &block
  receiver = block.binding.eval("self")
  start_constants = receiver.constants

  has_const_missing = receiver.methods(false).include? :const_missing
  receiver.const_set :ENUM_DUMMY_VALUE, -step

  receiver.singleton_class.instance_eval {
    if has_const_missing
      alias_method :tmp_enum_const_missing, :const_missing
    end

    define_method :const_missing do |name|
      const_set(name, const_get(constants.last) + step)
    end
    block.call

    remove_method :const_missing

    if has_const_missing
      alias_method :const_missing, :tmp_enum_const_missing
    end
  }

  receiver.__send__ :remove_const, :ENUM_DUMMY_VALUE
  Hash[(receiver.constants - start_constants).map{ |it| [it, receiver.const_get(it)] }]
end