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diff --git a/lib/puppet/event-loop/better-definers.rb b/lib/puppet/event-loop/better-definers.rb
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+## better-definers.rb --- better attribute and method definers
+# Copyright (C) 2005  Daniel Brockman
+
+# This program is free software; you can redistribute it
+# and/or modify it under the terms of the GNU General Public
+# License as published by the Free Software Foundation;
+# either version 2 of the License, or (at your option) any
+# later version.
+
+# This file is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty
+# of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+# See the GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public
+# License along with this program; if not, write to the Free
+# Software Foundation, 51 Franklin Street, Fifth Floor,
+# Boston, MA 02110-1301, USA.
+
+class Symbol
+  def predicate?
+    to_s.include? "?" end
+  def imperative?
+    to_s.include? "!" end
+  def writer?
+    to_s.include? "=" end
+
+  def punctuated?
+    predicate? or imperative? or writer? end
+  def without_punctuation
+    to_s.delete("?!=").to_sym end
+
+  def predicate
+    without_punctuation.to_s + "?" end
+  def imperative
+    without_punctuation.to_s + "!" end
+  def writer
+    without_punctuation.to_s + "=" end
+end
+
+class Hash
+  def collect! (&block)
+    replace Hash[*collect(&block).flatten]
+  end
+
+  def flatten
+    to_a.flatten
+  end
+end
+
+module Kernel
+  def returning (value)
+    yield value ; value
+  end
+end
+
+class Module
+  def define_hard_aliases (name_pairs)
+    for new_aliases, existing_name in name_pairs do
+      new_aliases.kind_of? Array or new_aliases = [new_aliases]
+      for new_alias in new_aliases do
+        alias_method(new_alias, existing_name)
+      end
+    end
+  end
+
+  def define_soft_aliases (name_pairs)
+    for new_aliases, existing_name in name_pairs do
+      new_aliases.kind_of? Array or new_aliases = [new_aliases]
+      for new_alias in new_aliases do
+        class_eval %{def #{new_alias}(*args, &block)
+                       #{existing_name}(*args, &block) end}
+      end
+    end
+  end
+
+  define_soft_aliases \
+    :define_hard_alias => :define_hard_aliases,
+    :define_soft_alias => :define_soft_aliases
+
+  # This method lets you define predicates like :foo?,
+  # which will be defined to return the value of @foo.
+  def define_readers (*names)
+    for name in names.map { |x| x.to_sym } do
+      if name.punctuated?
+        # There's no way to define an efficient reader whose
+        # name is different from the instance variable.
+        class_eval %{def #{name} ; @#{name.without_punctuation} end}
+      else
+        # Use `attr_reader' to define an efficient method.
+        attr_reader(name)
+      end
+    end
+  end
+
+  def writer_defined? (name)
+    method_defined? name.to_sym.writer
+  end
+
+  # If you pass a predicate symbol :foo? to this method, it'll first
+  # define a regular writer method :foo, without a question mark.
+  # Then it'll define an imperative writer method :foo! as a shorthand
+  # for setting the property to true.
+  def define_writers (*names, &body)
+    for name in names.map { |x| x.to_sym } do
+      if block_given?
+        define_method(name.writer, &body)
+      else
+        attr_writer(name.without_punctuation)
+      end
+      if name.predicate?
+        class_eval %{def #{name.imperative}
+                       self.#{name.writer} true end}
+      end
+    end
+  end
+
+  define_soft_aliases \
+    :define_reader => :define_readers,
+    :define_writer => :define_writers
+
+  # We don't need a singular alias for `define_accessors',
+  # because it always defines at least two methods.
+
+  def define_accessors (*names)
+    define_readers(*names)
+    define_writers(*names)
+  end
+
+  def define_opposite_readers (name_pairs)
+    name_pairs.collect! { |k, v| [k.to_sym, v.to_sym] }
+    for opposite_name, name in name_pairs do
+      define_reader(name) unless method_defined? name
+      class_eval %{def #{opposite_name} ; not #{name} end}
+    end
+  end
+
+  def define_opposite_writers (name_pairs)
+    name_pairs.collect! { |k, v| [k.to_sym, v.to_sym] }
+    for opposite_name, name in name_pairs do
+      define_writer(name) unless writer_defined? name
+      class_eval %{def #{opposite_name.writer} x
+                     self.#{name.writer} !x end} 
+      class_eval %{def #{opposite_name.imperative}
+                     self.#{name.writer} false end}
+    end
+  end
+
+  define_soft_aliases \
+    :define_opposite_reader => :define_opposite_readers,
+    :define_opposite_writer => :define_opposite_writers
+
+  def define_opposite_accessors (name_pairs)
+    define_opposite_readers name_pairs
+    define_opposite_writers name_pairs
+  end
+
+  def define_reader_with_opposite (name_pair, &body)
+    name, opposite_name = name_pair.flatten.collect { |x| x.to_sym }
+    define_method(name, &body)
+    define_opposite_reader(opposite_name => name)
+  end
+
+  def define_writer_with_opposite (name_pair, &body)
+    name, opposite_name = name_pair.flatten.collect { |x| x.to_sym }
+    define_writer(name, &body)
+    define_opposite_writer(opposite_name => name)
+  end
+
+  public :define_method
+
+  def define_methods (*names, &body)
+    names.each { |name| define_method(name, &body) }
+  end
+  
+  def define_private_methods (*names, &body)
+    define_methods(*names, &body)
+    names.each { |name| private name }
+  end
+
+  def define_protected_methods (*names, &body)
+    define_methods(*names, &body)
+    names.each { |name| protected name }
+  end
+
+  def define_private_method (name, &body)
+    define_method(name, &body)
+    private name
+  end
+
+  def define_protected_method (name, &body)
+    define_method(name, &body)
+    protected name
+  end
+end
+
+class ImmutableAttributeError < StandardError
+  def initialize (attribute=nil, message=nil)
+    super message
+    @attribute = attribute
+  end
+
+  define_accessors :attribute
+
+  def to_s
+    if @attribute and @message
+      "cannot change the value of `#@attribute': #@message"
+    elsif @attribute
+      "cannot change the value of `#@attribute'"
+    elsif @message
+      "cannot change the value of attribute: #@message"
+    else
+      "cannot change the value of attribute"
+    end
+  end
+end
+
+class Module
+  # Guard each of the specified attributes by replacing the writer
+  # method with a proxy that asks the supplied block before proceeding
+  # with the change.
+  #
+  # If it's okay to change the attribute, the block should return
+  # either nil or the symbol :mutable.  If it isn't okay, the block
+  # should return a string saying why the attribute can't be changed.
+  # If you don't want to provide a reason, you can have the block
+  # return just the symbol :immutable.
+  def guard_writers(*names, &predicate)
+    for name in names.map { |x| x.to_sym } do
+      define_hard_alias("__unguarded_#{name.writer}" => name.writer)
+      define_method(name.writer) do |new_value|
+        case result = predicate.call
+        when :mutable, nil
+          __send__("__unguarded_#{name.writer}", new_value)
+        when :immutable
+          raise ImmutableAttributeError.new(name)
+        else
+          raise ImmutableAttributeError.new(name, result)
+        end
+      end
+    end
+  end
+
+  def define_guarded_writers (*names, &block)
+    define_writers(*names)
+    guard_writers(*names, &block)
+  end
+
+  define_soft_alias :guard_writer => :guard_writers
+  define_soft_alias :define_guarded_writer => :define_guarded_writers
+end
+
+if __FILE__ == $0
+  require "test/unit"
+
+  class DefineAccessorsTest < Test::Unit::TestCase
+    def setup
+      @X = Class.new
+      @Y = Class.new @X
+      @x = @X.new
+      @y = @Y.new
+    end
+
+    def test_define_hard_aliases
+      @X.define_method(:foo) { 123 }
+      @X.define_method(:baz) { 321 }
+      @X.define_hard_aliases :bar => :foo, :quux => :baz
+      assert_equal @x.foo, 123
+      assert_equal @x.bar, 123
+      assert_equal @y.foo, 123
+      assert_equal @y.bar, 123
+      assert_equal @x.baz, 321
+      assert_equal @x.quux, 321
+      assert_equal @y.baz, 321
+      assert_equal @y.quux, 321
+      @Y.define_method(:foo) { 456 }
+      assert_equal @y.foo, 456
+      assert_equal @y.bar, 123
+      @Y.define_method(:quux) { 654 }
+      assert_equal @y.baz, 321
+      assert_equal @y.quux, 654
+    end
+    
+    def test_define_soft_aliases
+      @X.define_method(:foo) { 123 }
+      @X.define_method(:baz) { 321 }
+      @X.define_soft_aliases :bar => :foo, :quux => :baz
+      assert_equal @x.foo, 123
+      assert_equal @x.bar, 123
+      assert_equal @y.foo, 123
+      assert_equal @y.bar, 123
+      assert_equal @x.baz, 321
+      assert_equal @x.quux, 321
+      assert_equal @y.baz, 321
+      assert_equal @y.quux, 321
+      @Y.define_method(:foo) { 456 }
+      assert_equal @y.foo, @y.bar, 456
+      @Y.define_method(:quux) { 654 }
+      assert_equal @y.baz, 321
+      assert_equal @y.quux, 654
+    end
+
+    def test_define_readers
+      @X.define_readers :foo, :bar
+      assert !@x.respond_to?(:foo=)
+      assert !@x.respond_to?(:bar=)
+      @x.instance_eval { @foo = 123 ; @bar = 456 }
+      assert_equal @x.foo, 123
+      assert_equal @x.bar, 456
+      @X.define_readers :baz?, :quux?
+      assert !@x.respond_to?(:baz=)
+      assert !@x.respond_to?(:quux=)
+      @x.instance_eval { @baz = false ; @quux = true }
+      assert !@x.baz?
+      assert @x.quux?
+    end
+
+    def test_define_writers
+      assert !@X.writer_defined?(:foo)
+      assert !@X.writer_defined?(:bar)
+      @X.define_writers :foo, :bar
+      assert @X.writer_defined?(:foo)
+      assert @X.writer_defined?(:bar)
+      assert @X.writer_defined?(:foo=)
+      assert @X.writer_defined?(:bar=)
+      assert @X.writer_defined?(:foo?)
+      assert @X.writer_defined?(:bar?)
+      assert !@x.respond_to?(:foo)
+      assert !@x.respond_to?(:bar)
+      @x.foo = 123
+      @x.bar = 456
+      assert_equal @x.instance_eval { @foo }, 123
+      assert_equal @x.instance_eval { @bar }, 456
+      @X.define_writers :baz?, :quux?
+      assert !@x.respond_to?(:baz?)
+      assert !@x.respond_to?(:quux?)
+      @x.baz = true
+      @x.quux = false
+      assert_equal @x.instance_eval { @baz }, true
+      assert_equal @x.instance_eval { @quux }, false
+    end
+
+    def test_define_accessors
+      @X.define_accessors :foo, :bar
+      @x.foo = 123 ; @x.bar = 456
+      assert_equal @x.foo, 123
+      assert_equal @x.bar, 456
+    end
+
+    def test_define_opposite_readers
+      @X.define_opposite_readers :foo? => :bar?, :baz? => :quux?
+      assert !@x.respond_to?(:foo=)
+      assert !@x.respond_to?(:bar=)
+      assert !@x.respond_to?(:baz=)
+      assert !@x.respond_to?(:quux=)
+      @x.instance_eval { @bar = true ; @quux = false }
+      assert !@x.foo?
+      assert @x.bar?
+      assert @x.baz?
+      assert !@x.quux?
+    end
+
+    def test_define_opposite_writers
+      @X.define_opposite_writers :foo? => :bar?, :baz => :quux
+    end
+  end
+end