+ Enumerable#chunk_while (Ruby 2.3)

README.rdoc

@@ -79,6 +79,7 @@ Compatible with Ruby itself, JRuby and Rubinius.
   * +bsearch_index+
   * +dig+
 * Enumerable
+  * +chunk_while+
   * +grep_v+
 * Hash
   * +dig+

lib/backports/2.3.0/enumerable/chunk_while.rb

@@ -0,0 +1,27 @@
+unless Enumerable.method_defined? :chunk_while
+  require 'backports/tools/arguments'
+  require 'backports/1.9.1/enumerator/new'
+
+  module Enumerable
+    def chunk_while(&block)
+      raise ArgumentError, 'tried to create Proc object without a block' unless block
+      enum = self
+      Enumerator.new do |y|
+        acc = []
+        prev = Backports::Undefined
+        enum.each do |*elem|
+          elem = elem.first if elem.length == 1
+          unless prev == Backports::Undefined
+            unless block.call(prev, elem)
+              y.yield acc
+              acc = []
+            end
+          end
+          acc << elem
+          prev = elem
+        end
+        y.yield acc unless acc.empty?
+      end
+    end
+  end
+end