Module: Fattr

Included in:
Module
Defined in:
lib/fattr.rb,
lib/fattr/_lib.rb,
lib/fattr/version.rb

Defined Under Namespace

Classes: List, Result

Constant Summary collapse

SEMAPHORE = 
Mutex.new
Version = 
'2.3.0'

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.description ⇒ Object 



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# File 'lib/fattr/_lib.rb', line 6

def Fattr.description
  'a "fatter attr" for ruby'
end

.version ⇒ Object 



4
 
# File 'lib/fattr/_lib.rb', line 4

def Fattr.version() Fattr::Version end

Instance Method Details

#fattrs(*args, &block) ⇒ Object 



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# File 'lib/fattr.rb', line 61

def fattrs(*args, &block)
  unless args.empty?
    returned = Fattr::Result.new

    args.flatten!
    args.compact!

    all_hashes = args.all?{|arg| Hash===arg}

    names_and_configs = {}

    if all_hashes
      args.each do |hash|
        hash.each do |key, val|
          name = key.to_s
          config = Hash===val ? val : {:default => val}
          names_and_configs[name] = config
        end
      end
    else
      config = Hash===args.last ? args.pop : {}
      names = args.select{|arg| Symbol===arg or String===arg}.map{|arg| arg.to_s}
      names.each do |name|
        names_and_configs[name] = config
      end
    end

    #initializers = __fattrs__.initializers

    names_and_configs.each do |name, _config|
      raise(NameError, "bad instance variable name '@#{ name }'") if("@#{ name }" =~ %r/[!?=]$/o)

      name = name.to_s

      default = nil
      default = _config[:default] if _config.has_key?(:default)
      default = _config['default'] if _config.has_key?('default')

      inheritable = false
      if Module===self
        inheritable = _config[:inheritable] if _config.has_key?(:inheritable)
        inheritable = _config['inheritable'] if _config.has_key?('inheritable')
      end

      initialize = (
        if inheritable
          lambda do |*ignored|
            parents = ancestors[1..-1]
            catch(:value) do
              parents.each do |parent|
                throw(:value, parent.send(name)) if parent.respond_to?(name)
              end
              block ? block.call : default
            end
          end
        else
          block || lambda{|*ignored| default }
        end
      )

      initializer = lambda do |this|
        Object.instance_method('instance_eval').bind(this).call(&initialize)
      end

      #initializer_id = initializer.object_id

      __fattrs__.initializers[name] = initializer

      compile = lambda do |code|
        begin
          module_eval(code)
        rescue SyntaxError
          raise(SyntaxError, "\n#{ code }\n")
        end
      end

    # setter, block invocation caches block
      code = <<-code
        def #{ name }=(*value, &block)
          value.unshift block if block
          @#{ name } = value.first
        end
      code
      compile[code]

    # getter, providing a value or block causes it to acts as setter
      code = <<-code
        def #{ name }(*value, &block)
          value.unshift block if block
          return self.send('#{ name }=', value.first) unless value.empty?
          #SEMAPHORE.synchronize{ #{ name }! unless defined? @#{ name } }
          #{ name }! unless defined? @#{ name }
          @#{ name }
        end
      code
      compile[code]

    # bang method re-calls any initializer given at declaration time
=begin
      code = <<-code
        def #{ name }!
          initializer = ObjectSpace._id2ref #{ initializer_id }
          self.#{ name } = initializer.call(self)
          @#{ name }
        end
      code
      compile[code]
=end

      module_eval do
        define_method :"#{ name }!" do
          self.send :"#{ name }=", initializer.call(self)
          self.instance_variable_get :"@#{name}"
        end
      end

    # query simply defers to getter - cast to bool
      code = <<-code
        def #{ name }?
          self.#{ name }
        end
      code
      compile[code]

      fattrs << name
      returned[name] = initializer
    end

    returned
  else
    begin
      __fattr_list__
    rescue NameError, TypeError
      singleton_class =
        class << self
          self
        end
      klass = self
      singleton_class.module_eval do
        fattr_list = List.new
        define_method('fattr_list'){ klass == self ? fattr_list : raise(NameError) }
        alias_method '__fattr_list__', 'fattr_list'
      end
      __fattr_list__
    end
  end
end