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Diffstat (limited to 'lib/puppet/event-loop/better-definers.rb')
-rw-r--r-- | lib/puppet/event-loop/better-definers.rb | 367 |
1 files changed, 0 insertions, 367 deletions
diff --git a/lib/puppet/event-loop/better-definers.rb b/lib/puppet/event-loop/better-definers.rb deleted file mode 100644 index 0af37da62..000000000 --- a/lib/puppet/event-loop/better-definers.rb +++ /dev/null @@ -1,367 +0,0 @@ -## 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 |