Promote observer to default gems. But not yet released

doc/maintainers.rdoc

@@ -64,8 +64,6 @@ Zachary Scott (zzak)
   NARUSE, Yui (naruse)
 [lib/net/protocol.rb]
   _unmaintained_
-[lib/observer.rb]
-  _unmaintained_
 [lib/open-uri.rb]
   Tanaka Akira (akr)
 [lib/optparse.rb, lib/optparse/*]
@@ -213,6 +211,9 @@ Zachary Scott (zzak)
   _unmaintained_
   https://github.com/ruby/net-smtp
   https://rubygems.org/gems/net-smtp
+[lib/observer.rb]
+  _unmaintained_
+  https://github.com/ruby/observer
 [lib/open3.rb]
   _unmaintained_
   https://github.com/ruby/open3

doc/standard_library.rdoc

@@ -20,7 +20,6 @@ Monitor:: Provides an object or module to use safely by more than one thread
 Net::FTP:: Support for the File Transfer Protocol
 Net::HTTP:: HTTP client api for Ruby
 Net::IMAP:: Ruby client api for Internet Message Access Protocol
-Observable:: Provides a mechanism for publish/subscribe pattern in Ruby
 OpenURI:: An easy-to-use wrapper for Net::HTTP, Net::HTTPS and Net::FTP
 OptionParser:: Ruby-oriented class for command-line option analysis
 PP:: Provides a PrettyPrinter for Ruby objects
@@ -78,6 +77,7 @@ Matrix:: Represents a mathematical matrix.
 Mutex_m:: Mixin to extend objects to be handled like a Mutex
 Net::POP3:: Ruby client library for POP3
 Net::SMTP:: Simple Mail Transfer Protocol client library for Ruby
+Observable:: Provides a mechanism for publish/subscribe pattern in Ruby
 Open3:: Provides access to stdin, stdout and stderr when running other programs
 OpenStruct:: Class to build custom data structures, similar to a Hash
 Prime:: Prime numbers and factorization library

lib/observer/observer.gemspec

@@ -0,0 +1,29 @@
+begin
+  require_relative "lib/observer/version"
+rescue LoadError # Fallback to load version file in ruby core repository
+  require_relative "version"
+end
+
+Gem::Specification.new do |spec|
+  spec.name          = "observer"
+  spec.version       = Observer::VERSION
+  spec.authors       = ["Yukihiro Matsumoto"]
+  spec.email         = ["matz@ruby-lang.org"]
+
+  spec.summary       = %q{Implementation of the Observer object-oriented design pattern.}
+  spec.description   = spec.summary
+  spec.homepage      = "https://github.com/ruby/observer"
+  spec.license       = "BSD-2-Clause"
+
+  spec.metadata["homepage_uri"] = spec.homepage
+  spec.metadata["source_code_uri"] = spec.homepage
+
+  # Specify which files should be added to the gem when it is released.
+  # The `git ls-files -z` loads the files in the RubyGem that have been added into git.
+  spec.files         = Dir.chdir(File.expand_path('..', __FILE__)) do
+    `git ls-files -z`.split("\x0").reject { |f| f.match(%r{^(test|spec|features)/}) }
+  end
+  spec.bindir        = "exe"
+  spec.executables   = spec.files.grep(%r{^exe/}) { |f| File.basename(f) }
+  spec.require_paths = ["lib"]
+end

lib/observer/version.rb

@@ -0,0 +1,3 @@
+module Observer
+  VERSION = "0.1.0"
+end

tool/sync_default_gems.rb

@@ -44,6 +44,7 @@
 # * https://github.com/ruby/cgi
 # * https://github.com/ruby/readline
 # * https://github.com/ruby/readline-ext
+# * https://github.com/ruby/observer
 #
 
 require 'fileutils'
@@ -94,7 +95,8 @@ $repositories = {
   netsmtp: "ruby/net-smtp",
   cgi: "ruby/cgi",
   readline: "ruby/readline",
-  readlineext: "ruby/readline-ext"
+  readlineext: "ruby/readline-ext",
+  observer: "ruby/observer",
 }
 
 def sync_default_gems(gem)