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# Note: Must be required explicitely!
# This is a best attempt to fake BasicObject in Ruby 1.8.x
# What you do get:
# * as few methods as the real BasicObject (at the moment the library is required...)
# * BasicObject === <anything> # ==> returns true
# What you don't get:
# * BasicObject is not in the ancestor list of all classes and thus
# * Comparisons between classes won't work, e.g.
# Object < BasicObject # ==> returns true instead of false
# * Instance methods added to Object or Kernel after you require 'backports/basic_object'
# might also be available in instances of BasicObject and subclasses
# (they will only be undefined whenever a subclass of BasicObject is created)
# Because of all the fineprint, BasicObject must be required explicitely
unless Object.const_defined? :BasicObject
class BasicObject
KEEP = %w[== equal? ! != instance_eval instance_exec __send__]
KEEP.concat KEEP.map { |e| e.to_sym }
# undefine almost all instance methods
begin
old_verbose, $VERBOSE = $VERBOSE, nil # silence the warning for undefining __id__
(instance_methods - KEEP).each do |method|
undef_method method
end
ensure
$VERBOSE = old_verbose
end
class << self
def === (cmp)
true
end
# Let's try to keep things clean, in case methods have been added to Object
# either directly or through an included module.
# We'll do this whenever a class is derived from BasicObject
# Ideally, we'd do this by trapping Object.method_added
# and M.method_added for any module M included in Object or a submodule
# Seems really though to get right, but pull requests welcome ;-)
def inherited(sub)
BasicObject.class_eval do
(instance_methods - KEEP).each do |method|
if Object.method_defined?(method) && instance_method(method).owner == Object.instance_method(method).owner
undef_method method
end
end
end
end
end
end
end
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