twitter-status-bot/.gems/gems/naught-1.0.0/lib/naught/null_class_builder.rb

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2014-09-03 08:49:59 +00:00
require 'naught/basic_object'
require 'naught/conversions'
module Naught
class NullClassBuilder
# make sure this module exists
module Commands
end
attr_accessor :base_class, :inspect_proc, :interface_defined
def initialize
@interface_defined = false
@base_class = Naught::BasicObject
@inspect_proc = lambda { '<null>' }
@stub_strategy = :stub_method_returning_nil
define_basic_methods
end
def interface_defined?
!!@interface_defined
end
def customize(&customization_block)
return unless customization_block
customization_module.module_exec(self, &customization_block)
end
def customization_module
@customization_module ||= Module.new
end
def null_equivalents
@null_equivalents ||= [nil]
end
def generate_class
respond_to_any_message unless interface_defined?
generation_mod = Module.new
customization_mod = customization_module # get a local binding
builder = self
apply_operations(operations, generation_mod)
null_class = Class.new(@base_class) do
const_set :GeneratedMethods, generation_mod
const_set :Customizations, customization_mod
const_set :NULL_EQUIVS, builder.null_equivalents
include Conversions
remove_const :NULL_EQUIVS
Conversions.instance_methods.each do |instance_method|
undef_method(instance_method)
end
const_set :Conversions, Conversions
include NullObjectTag
include generation_mod
include customization_mod
end
apply_operations(class_operations, null_class)
null_class
end
def method_missing(method_name, *args, &block)
command_name = command_name_for_method(method_name)
if Commands.const_defined?(command_name)
command_class = Commands.const_get(command_name)
command_class.new(self, *args, &block).call
else
super
end
end
if RUBY_VERSION >= '1.9'
def respond_to_missing?(method_name, include_private = false)
command_name = command_name_for_method(method_name)
Commands.const_defined?(command_name) || super
rescue NameError
super
end
else
def respond_to?(method_name, include_private = false)
command_name = command_name_for_method(method_name)
Commands.const_defined?(command_name) || super
rescue NameError
super
end
end
############################################################################
# Builder API
#
# See also the contents of lib/naught/null_class_builder/commands
############################################################################
def black_hole
@stub_strategy = :stub_method_returning_self
end
def respond_to_any_message
defer(:prepend => true) do |subject|
subject.module_eval do
def respond_to?(*)
true
end
end
stub_method(subject, :method_missing)
end
@interface_defined = true
end
def defer(options = {}, &deferred_operation)
list = options[:class] ? class_operations : operations
if options[:prepend]
list.unshift(deferred_operation)
else
list << deferred_operation
end
end
def stub_method(subject, name)
send(@stub_strategy, subject, name)
end
private
def define_basic_methods
define_basic_instance_methods
define_basic_class_methods
end
def apply_operations(operations, module_or_class)
operations.each do |operation|
operation.call(module_or_class)
end
end
def define_basic_instance_methods
defer do |subject|
subject.module_exec(@inspect_proc) do |inspect_proc|
define_method(:inspect, &inspect_proc)
def initialize(*)
end
end
end
end
def define_basic_class_methods
defer(:class => true) do |subject|
subject.module_eval do
class << self
alias_method :get, :new
end
klass = self
define_method(:class) { klass }
end
end
end
def class_operations
@class_operations ||= []
end
def operations
@operations ||= []
end
def stub_method_returning_nil(subject, name)
subject.module_eval do
define_method(name) { |*| nil }
end
end
def stub_method_returning_self(subject, name)
subject.module_eval do
define_method(name) { |*| self }
end
end
def command_name_for_method(method_name)
method_name.to_s.gsub(/(?:^|_)([a-z])/) { Regexp.last_match[1].upcase }
end
end
end