first commit

nghttp2/third-party/mruby/mrbgems/mruby-enumerator/mrbgem.rake

@@ -0,0 +1,6 @@
+MRuby::Gem::Specification.new('mruby-enumerator') do |spec|
+  spec.license = 'MIT'
+  spec.author  = 'mruby developers'
+  spec.add_dependency('mruby-fiber', :core => 'mruby-fiber')
+  spec.summary = 'Enumerator class'
+end

nghttp2/third-party/mruby/mrbgems/mruby-enumerator/mrblib/enumerator.rb

@@ -0,0 +1,689 @@
+##
+# enumerator.rb Enumerator class
+# See Copyright Notice in mruby.h
+
+##
+# A class which allows both internal and external iteration.
+#
+# An Enumerator can be created by the following methods.
+# - {Kernel#to_enum}
+# - {Kernel#enum_for}
+# - {Enumerator#initialize Enumerator.new}
+#
+# Most methods have two forms: a block form where the contents
+# are evaluated for each item in the enumeration, and a non-block form
+# which returns a new Enumerator wrapping the iteration.
+#
+#       enumerator = %w(one two three).each
+#       puts enumerator.class # => Enumerator
+#
+#       enumerator.each_with_object("foo") do |item, obj|
+#         puts "#{obj}: #{item}"
+#       end
+#
+#       # foo: one
+#       # foo: two
+#       # foo: three
+#
+#       enum_with_obj = enumerator.each_with_object("foo")
+#       puts enum_with_obj.class # => Enumerator
+#
+#       enum_with_obj.each do |item, obj|
+#         puts "#{obj}: #{item}"
+#       end
+#
+#       # foo: one
+#       # foo: two
+#       # foo: three
+#
+# This allows you to chain Enumerators together.  For example, you
+# can map a list's elements to strings containing the index
+# and the element as a string via:
+#
+#       puts %w[foo bar baz].map.with_index { |w, i| "#{i}:#{w}" }
+#       # => ["0:foo", "1:bar", "2:baz"]
+#
+# An Enumerator can also be used as an external iterator.
+# For example, Enumerator#next returns the next value of the iterator
+# or raises StopIteration if the Enumerator is at the end.
+#
+#       e = [1,2,3].each   # returns an enumerator object.
+#       puts e.next   # => 1
+#       puts e.next   # => 2
+#       puts e.next   # => 3
+#       puts e.next   # raises StopIteration
+#
+# You can use this to implement an internal iterator as follows:
+#
+#       def ext_each(e)
+#         while true
+#           begin
+#             vs = e.next_values
+#           rescue StopIteration
+#             return $!.result
+#           end
+#           y = yield(*vs)
+#           e.feed y
+#         end
+#       end
+#
+#       o = Object.new
+#
+#       def o.each
+#         puts yield
+#         puts yield(1)
+#         puts yield(1, 2)
+#         3
+#       end
+#
+#       # use o.each as an internal iterator directly.
+#       puts o.each {|*x| puts x; [:b, *x] }
+#       # => [], [:b], [1], [:b, 1], [1, 2], [:b, 1, 2], 3
+#
+#       # convert o.each to an external iterator for
+#       # implementing an internal iterator.
+#       puts ext_each(o.to_enum) {|*x| puts x; [:b, *x] }
+#       # => [], [:b], [1], [:b, 1], [1, 2], [:b, 1, 2], 3
+#
+class Enumerator
+  include Enumerable
+
+  ##
+  # @overload initialize(obj, method = :each, *args)
+  #
+  # Creates a new Enumerator object, which can be used as an
+  # Enumerable.
+  #
+  # In the first form, iteration is defined by the given block, in
+  # which a "yielder" object, given as block parameter, can be used to
+  # yield a value by calling the +yield+ method (aliased as +<<+):
+  #
+  #     fib = Enumerator.new do |y|
+  #       a = b = 1
+  #       loop do
+  #         y << a
+  #         a, b = b, a + b
+  #       end
+  #     end
+  #
+  #     p fib.take(10) # => [1, 1, 2, 3, 5, 8, 13, 21, 34, 55]
+  #
+  # In the second, deprecated, form, a generated Enumerator iterates over the
+  # given object using the given method with the given arguments passed. This
+  # form is left only for internal use.
+  #
+  # Use of this form is discouraged.  Use Kernel#enum_for or Kernel#to_enum
+  # instead.
+  def initialize(obj=NONE, meth=:each, *args, &block)
+    if block
+      obj = Generator.new(&block)
+    elsif obj == NONE
+      raise ArgumentError, "wrong number of arguments (given 0, expected 1+)"
+    end
+
+    @obj = obj
+    @meth = meth
+    @args = args
+    @fib = nil
+    @dst = nil
+    @lookahead = nil
+    @feedvalue = nil
+    @stop_exc = false
+  end
+  attr_accessor :obj, :meth, :args
+  attr_reader :fib
+
+  def initialize_copy(obj)
+    raise TypeError, "can't copy type #{obj.class}" unless obj.kind_of? Enumerator
+    raise TypeError, "can't copy execution context" if obj.fib
+    @obj = obj.obj
+    @meth = obj.meth
+    @args = obj.args
+    @fib = nil
+    @lookahead = nil
+    @feedvalue = nil
+    self
+  end
+
+  ##
+  # call-seq:
+  #   e.with_index(offset = 0) {|(*args), idx| ... }
+  #   e.with_index(offset = 0)
+  #
+  # Iterates the given block for each element with an index, which
+  # starts from +offset+.  If no block is given, returns a new Enumerator
+  # that includes the index, starting from +offset+
+  #
+  # +offset+:: the starting index to use
+  #
+  def with_index(offset=0, &block)
+    return to_enum :with_index, offset unless block
+
+    if offset.nil?
+      offset = 0
+    else
+      offset = offset.__to_int
+    end
+
+    n = offset - 1
+    enumerator_block_call do |*i|
+      n += 1
+      block.call i.__svalue, n
+    end
+  end
+
+  ##
+  # call-seq:
+  #   e.each_with_index {|(*args), idx| ... }
+  #   e.each_with_index
+  #
+  # Same as Enumerator#with_index(0), i.e. there is no starting offset.
+  #
+  # If no block is given, a new Enumerator is returned that includes the index.
+  #
+  def each_with_index(&block)
+    with_index(0, &block)
+  end
+
+  ##
+  # call-seq:
+  #   e.each_with_object(obj) {|(*args), obj| ... }
+  #   e.each_with_object(obj)
+  #   e.with_object(obj) {|(*args), obj| ... }
+  #   e.with_object(obj)
+  #
+  # Iterates the given block for each element with an arbitrary object, +obj+,
+  # and returns +obj+
+  #
+  # If no block is given, returns a new Enumerator.
+  #
+  # @example
+  #   to_three = Enumerator.new do |y|
+  #     3.times do |x|
+  #       y << x
+  #     end
+  #   end
+  #
+  #   to_three_with_string = to_three.with_object("foo")
+  #   to_three_with_string.each do |x,string|
+  #     puts "#{string}: #{x}"
+  #   end
+  #
+  #   # => foo:0
+  #   # => foo:1
+  #   # => foo:2
+  #
+  def with_object(object, &block)
+    return to_enum(:with_object, object) unless block
+
+    enumerator_block_call do |i|
+      block.call [i,object]
+    end
+    object
+  end
+
+  def inspect
+    if @args && @args.size > 0
+      args = @args.join(", ")
+      "#<#{self.class}: #{@obj.inspect}:#{@meth}(#{args})>"
+    else
+      "#<#{self.class}: #{@obj.inspect}:#{@meth}>"
+    end
+  end
+
+  ##
+  # call-seq:
+  #   enum.each { |elm| block }                    -> obj
+  #   enum.each                                    -> enum
+  #   enum.each(*appending_args) { |elm| block }   -> obj
+  #   enum.each(*appending_args)                   -> an_enumerator
+  #
+  # Iterates over the block according to how this Enumerator was constructed.
+  # If no block and no arguments are given, returns self.
+  #
+  # === Examples
+  #
+  #   Array.new(3)                     #=> [nil, nil, nil]
+  #   Array.new(3) { |i| i }           #=> [0, 1, 2]
+  #   Array.to_enum(:new, 3).to_a      #=> [0, 1, 2]
+  #   Array.to_enum(:new).each(3).to_a #=> [0, 1, 2]
+  #
+  #   obj = Object.new
+  #
+  #   def obj.each_arg(a, b=:b, *rest)
+  #     yield a
+  #     yield b
+  #     yield rest
+  #     :method_returned
+  #   end
+  #
+  #   enum = obj.to_enum :each_arg, :a, :x
+  #
+  #   enum.each.to_a                  #=> [:a, :x, []]
+  #   enum.each.equal?(enum)          #=> true
+  #   enum.each { |elm| elm }         #=> :method_returned
+  #
+  #   enum.each(:y, :z).to_a          #=> [:a, :x, [:y, :z]]
+  #   enum.each(:y, :z).equal?(enum)  #=> false
+  #   enum.each(:y, :z) { |elm| elm } #=> :method_returned
+  #
+  def each(*argv, &block)
+    obj = self
+    if 0 < argv.length
+      obj = self.dup
+      args = obj.args
+      if !args.empty?
+        args = args.dup
+        args.concat argv
+      else
+        args = argv.dup
+      end
+      obj.args = args
+    end
+    return obj unless block
+    enumerator_block_call(&block)
+  end
+
+  def enumerator_block_call(&block)
+    @obj.__send__ @meth, *@args, &block
+  end
+  private :enumerator_block_call
+
+  ##
+  # call-seq:
+  #   e.next   -> object
+  #
+  # Returns the next object in the enumerator, and move the internal position
+  # forward.  When the position reached at the end, StopIteration is raised.
+  #
+  # === Example
+  #
+  #   a = [1,2,3]
+  #   e = a.to_enum
+  #   p e.next   #=> 1
+  #   p e.next   #=> 2
+  #   p e.next   #=> 3
+  #   p e.next   #raises StopIteration
+  #
+  # Note that enumeration sequence by +next+ does not affect other non-external
+  # enumeration methods, unless the underlying iteration methods itself has
+  # side-effect
+  #
+  def next
+    next_values.__svalue
+  end
+
+  ##
+  # call-seq:
+  #   e.next_values   -> array
+  #
+  # Returns the next object as an array in the enumerator, and move the
+  # internal position forward.  When the position reached at the end,
+  # StopIteration is raised.
+  #
+  # This method can be used to distinguish <code>yield</code> and <code>yield
+  # nil</code>.
+  #
+  # === Example
+  #
+  #   o = Object.new
+  #   def o.each
+  #     yield
+  #     yield 1
+  #     yield 1, 2
+  #     yield nil
+  #     yield [1, 2]
+  #   end
+  #   e = o.to_enum
+  #   p e.next_values
+  #   p e.next_values
+  #   p e.next_values
+  #   p e.next_values
+  #   p e.next_values
+  #   e = o.to_enum
+  #   p e.next
+  #   p e.next
+  #   p e.next
+  #   p e.next
+  #   p e.next
+  #
+  #   ## yield args       next_values      next
+  #   #  yield            []               nil
+  #   #  yield 1          [1]              1
+  #   #  yield 1, 2       [1, 2]           [1, 2]
+  #   #  yield nil        [nil]            nil
+  #   #  yield [1, 2]     [[1, 2]]         [1, 2]
+  #
+  # Note that +next_values+ does not affect other non-external enumeration
+  # methods unless underlying iteration method itself has side-effect
+  #
+  def next_values
+    if @lookahead
+      vs = @lookahead
+      @lookahead = nil
+      return vs
+    end
+    raise @stop_exc if @stop_exc
+
+    curr = Fiber.current
+
+    if !@fib || !@fib.alive?
+      @dst = curr
+      @fib = Fiber.new do
+        result = each do |*args|
+          feedvalue = nil
+          Fiber.yield args
+          if @feedvalue
+            feedvalue = @feedvalue
+            @feedvalue = nil
+          end
+          feedvalue
+        end
+        @stop_exc = StopIteration.new "iteration reached an end"
+        @stop_exc.result = result
+        Fiber.yield nil
+      end
+      @lookahead = nil
+    end
+
+    vs = @fib.resume curr
+    if @stop_exc
+      @fib = nil
+      @dst = nil
+      @lookahead = nil
+      @feedvalue = nil
+      raise @stop_exc
+    end
+    vs
+  end
+
+  ##
+  # call-seq:
+  #   e.peek   -> object
+  #
+  # Returns the next object in the enumerator, but doesn't move the internal
+  # position forward.  If the position is already at the end, StopIteration
+  # is raised.
+  #
+  # === Example
+  #
+  #   a = [1,2,3]
+  #   e = a.to_enum
+  #   p e.next   #=> 1
+  #   p e.peek   #=> 2
+  #   p e.peek   #=> 2
+  #   p e.peek   #=> 2
+  #   p e.next   #=> 2
+  #   p e.next   #=> 3
+  #   p e.next   #raises StopIteration
+  #
+  def peek
+    peek_values.__svalue
+  end
+
+  ##
+  # call-seq:
+  #   e.peek_values   -> array
+  #
+  # Returns the next object as an array, similar to Enumerator#next_values, but
+  # doesn't move the internal position forward.  If the position is already at
+  # the end, StopIteration is raised.
+  #
+  # === Example
+  #
+  #   o = Object.new
+  #   def o.each
+  #     yield
+  #     yield 1
+  #     yield 1, 2
+  #   end
+  #   e = o.to_enum
+  #   p e.peek_values    #=> []
+  #   e.next
+  #   p e.peek_values    #=> [1]
+  #   p e.peek_values    #=> [1]
+  #   e.next
+  #   p e.peek_values    #=> [1, 2]
+  #   e.next
+  #   p e.peek_values    # raises StopIteration
+  #
+  def peek_values
+    if @lookahead.nil?
+      @lookahead = next_values
+    end
+    @lookahead.dup
+  end
+
+  ##
+  # call-seq:
+  #   e.rewind   -> e
+  #
+  # Rewinds the enumeration sequence to the beginning.
+  #
+  # If the enclosed object responds to a "rewind" method, it is called.
+  #
+  def rewind
+    @obj.rewind if @obj.respond_to? :rewind
+    @fib = nil
+    @dst = nil
+    @lookahead = nil
+    @feedvalue = nil
+    @stop_exc = false
+    self
+  end
+
+  ##
+  # call-seq:
+  #   e.feed obj   -> nil
+  #
+  # Sets the value to be returned by the next yield inside +e+.
+  #
+  # If the value is not set, the yield returns nil.
+  #
+  # This value is cleared after being yielded.
+  #
+  #   # Array#map passes the array's elements to "yield" and collects the
+  #   # results of "yield" as an array.
+  #   # Following example shows that "next" returns the passed elements and
+  #   # values passed to "feed" are collected as an array which can be
+  #   # obtained by StopIteration#result.
+  #   e = [1,2,3].map
+  #   p e.next           #=> 1
+  #   e.feed "a"
+  #   p e.next           #=> 2
+  #   e.feed "b"
+  #   p e.next           #=> 3
+  #   e.feed "c"
+  #   begin
+  #     e.next
+  #   rescue StopIteration
+  #     p $!.result      #=> ["a", "b", "c"]
+  #   end
+  #
+  #   o = Object.new
+  #   def o.each
+  #     x = yield         # (2) blocks
+  #     p x               # (5) => "foo"
+  #     x = yield         # (6) blocks
+  #     p x               # (8) => nil
+  #     x = yield         # (9) blocks
+  #     p x               # not reached w/o another e.next
+  #   end
+  #
+  #   e = o.to_enum
+  #   e.next              # (1)
+  #   e.feed "foo"        # (3)
+  #   e.next              # (4)
+  #   e.next              # (7)
+  #                       # (10)
+  #
+  def feed(value)
+    raise TypeError, "feed value already set" if @feedvalue
+    @feedvalue = value
+    nil
+  end
+
+  # just for internal
+  class Generator
+    include Enumerable
+    def initialize(&block)
+      raise TypeError, "wrong argument type #{self.class} (expected Proc)" unless block.kind_of? Proc
+
+      @proc = block
+    end
+
+    def each(*args, &block)
+      args.unshift Yielder.new(&block)
+      @proc.call(*args)
+    end
+  end
+
+  # just for internal
+  class Yielder
+    def initialize(&block)
+      raise LocalJumpError, "no block given" unless block
+
+      @proc = block
+    end
+
+    def yield(*args)
+      @proc.call(*args)
+    end
+
+    def << *args
+      self.yield(*args)
+      self
+    end
+  end
+
+  ##
+  # call-seq:
+  #    Enumerator.produce(initial = nil) { |val| } -> enumerator
+  #
+  # Creates an infinite enumerator from any block, just called over and
+  # over.  Result of the previous iteration is passed to the next one.
+  # If +initial+ is provided, it is passed to the first iteration, and
+  # becomes the first element of the enumerator; if it is not provided,
+  # first iteration receives +nil+, and its result becomes first
+  # element of the iterator.
+  #
+  # Raising StopIteration from the block stops an iteration.
+  #
+  # Examples of usage:
+  #
+  #   Enumerator.produce(1, &:succ)   # => enumerator of 1, 2, 3, 4, ....
+  #
+  #   Enumerator.produce { rand(10) } # => infinite random number sequence
+  #
+  #   ancestors = Enumerator.produce(node) { |prev| node = prev.parent or raise StopIteration }
+  #   enclosing_section = ancestors.find { |n| n.type == :section }
+  def Enumerator.produce(init=NONE, &block)
+    raise ArgumentError, "no block given" if block.nil?
+    Enumerator.new do |y|
+      if init == NONE
+        val = nil
+      else
+        val = init
+        y.yield(val)
+      end
+      begin
+        while true
+          y.yield(val = block.call(val))
+        end
+      rescue StopIteration
+        # do nothing
+      end
+    end
+  end
+end
+
+module Kernel
+  ##
+  # call-seq:
+  #   obj.to_enum(method = :each, *args)                 -> enum
+  #   obj.enum_for(method = :each, *args)                -> enum
+  #
+  # Creates a new Enumerator which will enumerate by calling +method+ on
+  # +obj+, passing +args+ if any.
+  #
+  # === Examples
+  #
+  #   str = "xyz"
+  #
+  #   enum = str.enum_for(:each_byte)
+  #   enum.each { |b| puts b }
+  #   # => 120
+  #   # => 121
+  #   # => 122
+  #
+  #   # protect an array from being modified by some_method
+  #   a = [1, 2, 3]
+  #   some_method(a.to_enum)
+  #
+  # It is typical to call to_enum when defining methods for
+  # a generic Enumerable, in case no block is passed.
+  #
+  # Here is such an example with parameter passing:
+  #
+  #     module Enumerable
+  #       # a generic method to repeat the values of any enumerable
+  #       def repeat(n)
+  #         raise ArgumentError, "#{n} is negative!" if n < 0
+  #         unless block_given?
+  #           return to_enum(__method__, n) # __method__ is :repeat here
+  #         end
+  #         each do |*val|
+  #           n.times { yield *val }
+  #         end
+  #       end
+  #     end
+  #
+  #     %i[hello world].repeat(2) { |w| puts w }
+  #       # => Prints 'hello', 'hello', 'world', 'world'
+  #     enum = (1..14).repeat(3)
+  #       # => returns an Enumerator when called without a block
+  #     enum.first(4) # => [1, 1, 1, 2]
+  #
+  def to_enum(meth=:each, *args)
+    Enumerator.new self, meth, *args
+  end
+  alias enum_for to_enum
+end
+
+module Enumerable
+  # use Enumerator to use infinite sequence
+  def zip(*args, &block)
+    args = args.map do |a|
+      if a.respond_to?(:each)
+        a.to_enum(:each)
+      else
+        raise TypeError, "wrong argument type #{a.class} (must respond to :each)"
+      end
+    end
+
+    result = block ? nil : []
+
+    each do |*val|
+      tmp = [val.__svalue]
+      args.each do |arg|
+        v = if arg.nil?
+          nil
+        else
+          begin
+            arg.next
+          rescue StopIteration
+            nil
+          end
+        end
+        tmp.push(v)
+      end
+      if result.nil?
+        block.call(tmp)
+      else
+        result.push(tmp)
+      end
+    end
+
+    result
+  end
+end

nghttp2/third-party/mruby/mrbgems/mruby-enumerator/test/enumerator.rb

@@ -0,0 +1,600 @@
+@obj = Object.new
+class << @obj
+  include Enumerable
+  def foo *a
+    a.each { |x| yield x }
+  end
+end
+
+def assert_take(exp, enumerator)
+  result = []
+  n = exp.size
+  enumerator.each do |v|
+    result << v
+    n -= 1
+    break if n == 0
+  end if n > 0
+  assert_equal exp, result
+end
+
+assert 'Enumerator.class' do
+  assert_equal Class, Enumerator.class
+end
+
+assert 'Enumerator.superclass' do
+  assert_equal Object, Enumerator.superclass
+end
+
+assert 'Enumerator.new' do
+  assert_equal [0,1,2], 3.times.map{|i| i}.sort
+  assert_equal [:x,:y,:z], [:x,:y,:z].each.map{|i| i}.sort
+  assert_equal [[:x,1],[:y,2]], {x:1, y:2}.each.map{|i| i}.sort
+  assert_equal [1,2,3], @obj.to_enum(:foo, 1,2,3).to_a
+  assert_take [1,2,3], Enumerator.new { |y| i = 0; loop { y << (i += 1) } }
+  assert_raise(ArgumentError) { Enumerator.new }
+
+  # examples
+  fib = Enumerator.new do |y|
+    a = b = 1
+    loop do
+      y << a
+      a, b = b, a + b
+    end
+  end
+  assert_take [1,1,2,3,5,8,13,21,34,55], fib
+end
+
+assert 'Enumerator#initialize_copy' do
+  assert_equal [1, 2, 3], @obj.to_enum(:foo, 1, 2, 3).dup.to_a
+  e = @obj.to_enum :foo, 1, 2, 3
+  assert_nothing_raised { assert_equal(1, e.next) }
+  assert_raise(TypeError) { e.dup }
+
+  e = Enumerator.new { |y| i = 0; loop { y << (i += 1) } }.dup
+  assert_nothing_raised { assert_equal(1, e.next) }
+  assert_raise(TypeError) { e.dup }
+end
+
+assert 'Enumerator#with_index' do
+  assert_equal([[1,0],[2,1],[3,2]], @obj.to_enum(:foo, 1, 2, 3).with_index.to_a)
+  assert_equal([[1,5],[2,6],[3,7]], @obj.to_enum(:foo, 1, 2, 3).with_index(5).to_a)
+  a = []
+  @obj.to_enum(:foo, 1, 2, 3).with_index(10).with_index(20) { |*i| a << i }
+  assert_equal [[[1, 10], 20], [[2, 11], 21], [[3, 12], 22]], a
+end
+
+assert 'Enumerator#with_index string offset' do
+  assert_raise(TypeError){ @obj.to_enum(:foo, 1, 2, 3).with_index('1').to_a }
+end
+
+assert 'Enumerator#each_with_index' do
+  assert_equal([[1,0],[2,1],[3,2]], @obj.to_enum(:foo, 1, 2, 3).each_with_index.to_a)
+  a = []
+  @obj.to_enum(:foo, 1, 2, 3).each_with_index {|*i| a << i}
+  assert_equal([[1, 0], [2, 1], [3, 2]], a)
+end
+
+assert 'Enumerator#with_object' do
+  obj = [0, 1]
+  ret = (1..10).each.with_object(obj) {|i, memo|
+    memo[0] += i
+    memo[1] *= i
+  }
+  assert_true(obj.equal?(ret))
+  assert_equal([55, 3628800], ret)
+end
+
+assert 'Enumerator#with_object arguments' do
+  to_three = Enumerator.new do |y|
+    3.times do |x|
+      y << x
+    end
+  end
+
+  a = []
+  to_three_with_string = to_three.with_object("foo")
+  to_three_with_string.each do |x,string|
+    a << "#{string}:#{x}"
+  end
+  assert_equal ["foo:0","foo:1","foo:2"], a
+end
+
+assert 'Enumerator#inspect' do
+  e = (0..10).each
+  assert_equal('#<Enumerator: 0..10:each>', e.inspect)
+  e = 'FooObject'.enum_for(:foo, 1)
+  assert_equal('#<Enumerator: "FooObject":foo(1)>', e.inspect)
+  e = 'FooObject'.enum_for(:foo, 1, 2, 3)
+  assert_equal('#<Enumerator: "FooObject":foo(1, 2, 3)>', e.inspect)
+  e = nil.enum_for(:to_s)
+  assert_equal('#<Enumerator: nil:to_s>', e.inspect)
+end
+
+assert 'Enumerator#each' do
+  o = Object.new
+  def o.each(ary)
+    ary << 1
+    yield
+  end
+  ary = []
+  e = o.to_enum.each(ary)
+  e.next
+  assert_equal([1], ary)
+end
+
+assert 'Enumerator#each arguments' do
+  obj = Object.new
+
+  def obj.each_arg(a, b=:b, *rest)
+    yield a
+    yield b
+    yield rest
+    :method_returned
+  end
+
+  enum = obj.to_enum :each_arg, :a, :x
+
+  assert_equal [:a, :x, []], enum.each.to_a
+  assert_true enum.each.equal?(enum)
+  assert_equal :method_returned, enum.each { |elm| elm }
+
+  assert_equal [:a, :x, [:y, :z]], enum.each(:y, :z).to_a
+  assert_false enum.each(:y, :z).equal?(enum)
+  assert_equal :method_returned, enum.each(:y, :z) { |elm| elm }
+end
+
+assert 'Enumerator#next' do
+  e = 3.times
+  3.times { |i|
+    assert_equal i, e.next
+  }
+  assert_raise(StopIteration) { e.next }
+end
+
+assert 'Enumerator#next_values' do
+  o = Object.new
+  def o.each
+    yield
+    yield 1
+    yield 1, 2
+  end
+  e = o.to_enum
+  assert_equal nil, e.next
+  assert_equal 1, e.next
+  assert_equal [1,2], e.next
+  e = o.to_enum
+  assert_equal [], e.next_values
+  assert_equal [1], e.next_values
+  assert_equal [1,2], e.next_values
+end
+
+assert 'Enumerator#peek' do
+  a = [1]
+  e = a.each
+  assert_equal 1, e.peek
+  assert_equal 1, e.peek
+  assert_equal 1, e.next
+  assert_raise(StopIteration) { e.peek }
+  assert_raise(StopIteration) { e.peek }
+end
+
+assert 'Enumerator#peek modify' do
+  o = Object.new
+  def o.each
+    yield 1,2
+  end
+  e = o.to_enum
+  a = e.peek
+  a << 3
+  assert_equal([1,2], e.peek)
+end
+
+assert 'Enumerator#peek_values' do
+  o = Object.new
+  def o.each
+    yield
+    yield 1
+    yield 1, 2
+  end
+  e = o.to_enum
+  assert_equal nil, e.peek
+  assert_equal nil, e.next
+  assert_equal 1, e.peek
+  assert_equal 1, e.next
+  assert_equal [1,2], e.peek
+  assert_equal [1,2], e.next
+  e = o.to_enum
+  assert_equal [], e.peek_values
+  assert_equal [], e.next_values
+  assert_equal [1], e.peek_values
+  assert_equal [1], e.next_values
+  assert_equal [1,2], e.peek_values
+  assert_equal [1,2], e.next_values
+  e = o.to_enum
+  assert_equal [], e.peek_values
+  assert_equal nil, e.next
+  assert_equal [1], e.peek_values
+  assert_equal 1, e.next
+  assert_equal [1,2], e.peek_values
+  assert_equal [1,2], e.next
+  e = o.to_enum
+  assert_equal nil, e.peek
+  assert_equal [], e.next_values
+  assert_equal 1, e.peek
+  assert_equal [1], e.next_values
+  assert_equal [1,2], e.peek
+  assert_equal [1,2], e.next_values
+end
+
+assert 'Enumerator#peek_values modify' do
+  o = Object.new
+  def o.each
+    yield 1,2
+  end
+  e = o.to_enum
+  a = e.peek_values
+  a << 3
+  assert_equal [1,2], e.peek
+end
+
+assert 'Enumerator#feed' do
+  o = Object.new
+  def o.each(ary)
+    ary << yield
+    ary << yield
+    ary << yield
+  end
+  ary = []
+  e = o.to_enum :each, ary
+  e.next
+  e.feed 1
+  e.next
+  e.feed 2
+  e.next
+  e.feed 3
+  assert_raise(StopIteration) { e.next }
+  assert_equal [1,2,3], ary
+end
+
+assert 'Enumerator#feed mixed' do
+  o = Object.new
+  def o.each(ary)
+    ary << yield
+    ary << yield
+    ary << yield
+  end
+  ary = []
+  e = o.to_enum :each, ary
+  e.next
+  e.feed 1
+  e.next
+  e.next
+  e.feed 3
+  assert_raise(StopIteration) { e.next }
+  assert_equal [1,nil,3], ary
+end
+
+assert 'Enumerator#feed twice' do
+  o = Object.new
+  def o.each(ary)
+    ary << yield
+    ary << yield
+    ary << yield
+  end
+  ary = []
+  e = o.to_enum :each, ary
+  e.feed 1
+  assert_raise(TypeError) { e.feed 2 }
+end
+
+assert 'Enumerator#feed before first next' do
+  o = Object.new
+  def o.each(ary)
+    ary << yield
+    ary << yield
+    ary << yield
+  end
+  ary = []
+  e = o.to_enum :each, ary
+  e.feed 1
+  e.next
+  e.next
+  assert_equal [1], ary
+end
+
+assert 'Enumerator#feed yielder' do
+  x = nil
+  e = Enumerator.new {|y| x = y.yield; 10 }
+  e.next
+  e.feed 100
+  assert_raise(StopIteration) { e.next }
+  assert_equal 100, x
+end
+
+assert 'Enumerator#rewind' do
+  e = @obj.to_enum(:foo, 1, 2, 3)
+  assert_equal 1, e.next
+  assert_equal 2, e.next
+  e.rewind
+  assert_equal 1, e.next
+  assert_equal 2, e.next
+  assert_equal 3, e.next
+  assert_raise(StopIteration) { e.next }
+end
+
+assert 'Enumerator#rewind clear feed' do
+  o = Object.new
+  def o.each(ary)
+    ary << yield
+    ary << yield
+    ary << yield
+  end
+  ary = []
+  e = o.to_enum(:each, ary)
+  e.next
+  e.feed 1
+  e.next
+  e.feed 2
+  e.rewind
+  e.next
+  e.next
+  assert_equal([1,nil], ary)
+end
+
+assert 'Enumerator#rewind clear' do
+  o = Object.new
+  def o.each(ary)
+    ary << yield
+    ary << yield
+    ary << yield
+  end
+  ary = []
+  e = o.to_enum :each, ary
+  e.next
+  e.feed 1
+  e.next
+  e.feed 2
+  e.rewind
+  e.next
+  e.next
+  assert_equal [1,nil], ary
+end
+
+assert 'Enumerator::Generator' do
+  # note: Enumerator::Generator is a class just for internal
+  g = Enumerator::Generator.new {|y| y << 1 << 2 << 3; :foo }
+  g2 = g.dup
+  a = []
+  assert_equal(:foo, g.each {|x| a << x })
+  assert_equal([1, 2, 3], a)
+  a = []
+  assert_equal(:foo, g2.each {|x| a << x })
+  assert_equal([1, 2, 3], a)
+end
+
+assert 'Enumerator::Generator args' do
+  g = Enumerator::Generator.new {|y, x| y << 1 << 2 << 3; x }
+  a = []
+  assert_equal(:bar, g.each(:bar) {|x| a << x })
+  assert_equal([1, 2, 3], a)
+end
+
+assert 'Enumerator::Yielder' do
+  # note: Enumerator::Yielder is a class just for internal
+  a = []
+  y = Enumerator::Yielder.new {|x| a << x }
+  assert_equal(y, y << 1 << 2 << 3)
+  assert_equal([1, 2, 3], a)
+
+  a = []
+  y = Enumerator::Yielder.new {|x| a << x }
+  assert_equal([1], y.yield(1))
+  assert_equal([1, 2], y.yield(2))
+  assert_equal([1, 2, 3], y.yield(3))
+
+  assert_raise(LocalJumpError) { Enumerator::Yielder.new }
+end
+
+assert 'next after StopIteration' do
+  a = [1]
+  e = a.each
+  assert_equal(1, e.next)
+  assert_raise(StopIteration) { e.next }
+  assert_raise(StopIteration) { e.next }
+  e.rewind
+  assert_equal(1, e.next)
+  assert_raise(StopIteration) { e.next }
+  assert_raise(StopIteration) { e.next }
+end
+
+assert 'gc' do
+  assert_nothing_raised do
+    1.times do
+      foo = [1,2,3].to_enum
+      GC.start
+    end
+    GC.start
+  end
+end
+
+assert 'nested iteration' do
+  def (o = Object.new).each
+    yield :ok1
+    yield [:ok2, :x].each.next
+  end
+  e = o.to_enum
+  assert_equal :ok1, e.next
+  assert_equal :ok2, e.next
+  assert_raise(StopIteration) { e.next }
+end
+
+assert 'Kernel#to_enum' do
+  e = nil
+  assert_equal Enumerator, [].to_enum.class
+  assert_nothing_raised { e = [].to_enum(:_not_implemented_) }
+  assert_raise(NoMethodError) { e.first }
+end
+
+assert 'modifying existing methods' do
+  assert_equal Enumerator, loop.class
+  e = 3.times
+  i = 0
+  loop_ret = loop {
+    assert_equal i, e.next
+    i += 1
+  }
+end
+
+assert 'Integral#times' do
+  a = 3
+  b = a.times
+  c = []
+  b.with_object(c) do |i, obj|
+    obj << i
+  end
+  assert_equal 3, a
+  assert_equal Enumerator, b.class
+  assert_equal [0,1,2], c
+end
+
+assert 'Enumerable#each_with_index' do
+  assert_equal [['a',0],['b',1],['c',2]], ['a','b','c'].each_with_index.to_a
+end
+
+assert 'Enumerable#map' do
+  a = [1,2,3]
+  b = a.map
+  c = b.with_index do |i, index|
+    [i*i, index*index]
+  end
+  assert_equal [1,2,3], a
+  assert_equal [[1,0],[4,1],[9,4]], c
+end
+
+assert 'Enumerable#find_all' do
+  assert_equal [[3,4]], [[1,2],[3,4],[5,6]].find_all.each{ |i| i[1] == 4 }
+end
+
+assert 'Array#each_index' do
+  a = [1,2,3]
+  b = a.each_index
+  c = []
+  b.with_index do |index1,index2|
+    c << [index1+2,index2+5]
+  end
+  assert_equal [1,2,3], a
+  assert_equal [[2,5],[3,6],[4,7]], c
+end
+
+assert 'Array#map!' do
+  a = [1,2,3]
+  b = a.map!
+  b.with_index do |i, index|
+    [i*i, index*index]
+  end
+  assert_equal [[1,0],[4,1],[9,4]], a
+end
+
+assert 'Hash#each' do
+  a = {a:1,b:2}
+  b = a.each
+  c = []
+  b.each do |k,v|
+    c << [k,v]
+  end
+  assert_equal [[:a,1], [:b,2]], c.sort
+end
+
+assert 'Hash#each_key' do
+  assert_equal [:a,:b], {a:1,b:2}.each_key.to_a.sort
+end
+
+assert 'Hash#each_value' do
+  assert_equal [1,2], {a:1,b:2}.each_value.to_a.sort
+end
+
+assert 'Hash#select' do
+  h = {1=>2,3=>4,5=>6}
+  hret = h.select.with_index {|a,_b| a[1] == 4}
+  assert_equal({3=>4}, hret)
+  assert_equal({1=>2,3=>4,5=>6}, h)
+end
+
+assert 'Hash#select!' do
+  h = {1=>2,3=>4,5=>6}
+  hret = h.select!.with_index {|a,_b| a[1] == 4}
+  assert_equal h, hret
+  assert_equal({3=>4}, h)
+end
+
+assert 'Hash#reject' do
+  h = {1=>2,3=>4,5=>6}
+  hret = h.reject.with_index {|a,_b| a[1] == 4}
+  assert_equal({1=>2,5=>6}, hret)
+  assert_equal({1=>2,3=>4,5=>6}, h)
+end
+
+assert 'Hash#reject!' do
+  h = {1=>2,3=>4,5=>6}
+  hret = h.reject!.with_index {|a,_b| a[1] == 4}
+  assert_equal h, hret
+  assert_equal({1=>2,5=>6}, h)
+end
+
+assert 'Range#each' do
+  a = (1..5)
+  b = a.each
+  c = []
+  b.each do |i|
+    c << i
+  end
+  assert_equal [1,2,3,4,5], c
+end
+
+assert 'Enumerable#zip' do
+  assert_equal [[1, 10], [2, 11], [3, 12]], [1,2,3].zip(10..Float::INFINITY)
+
+  ret = []
+  assert_equal nil, [1,2,3].zip(10..Float::INFINITY) { |i| ret << i }
+  assert_equal [[1, 10], [2, 11], [3, 12]], ret
+
+  assert_raise(TypeError) { [1].zip(1) }
+end
+
+assert 'Enumerator.produce' do
+  assert_raise(ArgumentError) { Enumerator.produce }
+
+  # Without initial object
+  passed_args = []
+  enum = Enumerator.produce {|obj| passed_args << obj; (obj || 0).succ }
+  assert_equal Enumerator, enum.class 
+  assert_take [1, 2, 3], enum
+  assert_equal [nil, 1, 2], passed_args
+
+  # With initial object
+  passed_args = []
+  enum = Enumerator.produce(1) {|obj| passed_args << obj; obj.succ }
+  assert_take [1, 2, 3], enum
+  assert_equal [1, 2], passed_args
+
+  # Raising StopIteration
+  words = %w[The quick brown fox jumps over the lazy dog]
+  enum = Enumerator.produce { words.shift or raise StopIteration }
+  assert_equal %w[The quick brown fox jumps over the lazy dog], enum.to_a
+
+  # Raising StopIteration
+  object = [[[["abc", "def"], "ghi", "jkl"], "mno", "pqr"], "stuv", "wxyz"]
+  enum = Enumerator.produce(object) {|obj|
+    obj.respond_to?(:first) or raise StopIteration
+    obj.first
+  }
+  assert_nothing_raised {
+    assert_equal [
+      [[[["abc", "def"], "ghi", "jkl"], "mno", "pqr"], "stuv", "wxyz"],
+      [[["abc", "def"], "ghi", "jkl"], "mno", "pqr"],
+      [["abc", "def"], "ghi", "jkl"],
+      ["abc", "def"],
+      "abc",
+    ], enum.to_a
+  }
+end