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require 'facets/functor'
require 'facets/module/basename'
class Module
# Create method namespaces, allowing for method
# chains but still accessing the object's instance.
#
# class A
# attr_writer :x
# method_space :inside do
# def x; @x; end
# end
# end
#
# a = A.new
# a.x = 10
# a.inside.x #=> 10
#
# expect NoMethodError do
# a.x
# end
#
# NOTE: This is not (presently) a common core extension and is not
# loaded automatically when using <code>require 'facets'</code>.
#
# CREDIT: Pit Captain
def method_space(name, mod=nil, &blk)
## If block is given then create a module, otherwise
## get the name of the module.
if block_given?
name = name.to_s
raise ArgumentError if mod
mod = Module.new(&blk)
else
if Module === name
mod = name
name = mod.basename.downcase
end
mod = mod.dup
end
## Include the module. This is neccessary, otherwise
## Ruby won't let us bind the instance methods.
include mod
## Save the instance methods of the module and
## replace them with a "transparent" version.
methods = {}
mod.instance_methods(false).each do |m|
methods[m.to_sym] = mod.instance_method(m)
mod.module_eval %{
def #{m}(*a,&b)
super(*a,&b)
end
}
##mod.instance_eval do
## define_method(m)
## super
## end
##end
end
## Add a method for the namespace that delegates
## via the Functor to the saved instance methods.
define_method(name) do
mtab = methods
Functor.new do |op, *args|
if meth = mtab[op.to_sym]
meth.bind(self).call(*args)
else
#self.__send__(op, *args)
raise NoMethodError, "undefined method `#{m}'"
end
end
end
end
# Include a module via a specified space.
#
# module T
# def t ; "HERE" ; end
# end
#
# class X
# include_as :test => T
# def t ; test.t ; end
# end
#
# X.new.t #=> "HERE"
#
# NOTE: This is not (presently) a common core extension and is not
# loaded automatically when using <code>require 'facets'</code>.
def include_as(h)
h.each{ |name, mod| method_space(name, mod) }
end
end
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