Contents

class ImportError < Exception; end

module Kernel

  # abstraction:: only include the methods given by _meths_
  # implementation:: includes a duplicate of _mod_ with all uneeded instance methods removed
  def import(mod, *meths)
    mod_dup = mod.dup

    unless meths.empty?

      # get list of methods to remove module
      ims = mod.instance_methods.map {|m| m.to_sym}
      removes = ims - meths

      if removes.size != (ims.size - meths.size)
        raise ImportError, "##{(meths - ims).join(' and #')} not found in #{mod}"
      end

      mod_dup.module_eval do
        removes.each { |meth| remove_method meth }
      end
    end

    include mod_dup
  end
end
  module Foo
    def foo; 'foo' end
    def bar; 'bar' end
  end
  class Importer
    import Foo, :bar
  end
  Importer.new.bar # => 'bar'
  class Importer
  end
  class Importer2
    import Foo # same as import Foo, :foo, :bar
  end
  Importer2.new.bar # => 'bar'
  Importer2.new.foo # => 'foo'
  module Foo
    undef_method :foo
    def bar; fail end
  end
  Importer2.new.bar # => 'bar'
  Importer2.new.foo # => 'foo'

Version data entries

2 entries across 2 versions & 1 rubygems

Version	Path
module-import-0.2.2	./example.rb
module-import-0.3.0	./example.rb