Add limit options support to zrevrangebylex

Author: caulfield

lib/redis.rb

@@ -1620,6 +1620,28 @@ def zrangebylex(key, min, max, options = {})
     end
   end
 
+  # Return a range of members with the same score in a sorted set, by reversed lexicographical ordering.
+  # Apart from the reversed ordering, #zrevrangebylex is similar to #zrangebylex.
+  #
+  # @example Retrieve members matching a
+  #   redis.zrevrangebylex("zset", "[a", "[a\xff")
+  #     # => ["abbygail", "abby", "abagael", "aaren"]
+  # @example Retrieve the last 2 members matching a
+  #   redis.zrevrangebylex("zset", "[a", "[a\xff", :limit => [0, 2])
+  #     # => ["abbygail", "abby"]
+  #
+  # @see #zrangebylex
+  def zrevrangebylex(key, max, min, options = {})
+    args = []
+
+    limit = options[:limit]
+    args.concat(["LIMIT"] + limit) if limit
+
+    synchronize do |client|
+      client.call([:zrevrangebylex, key, max, min] + args)
+    end
+  end
+
   # Return a range of members in a sorted set, by score.
   #
   # @example Retrieve members with score `>= 5` and `< 100`

test/commands_on_sorted_sets_test.rb

@@ -22,6 +22,20 @@ def test_zrangebylex
     end
   end
 
+  def test_zrevrangebylex
+    target_version "2.9.9" do
+      r.zadd "foo", 0, "aaren"
+      r.zadd "foo", 0, "abagael"
+      r.zadd "foo", 0, "abby"
+      r.zadd "foo", 0, "abbygail"
+
+      assert_equal ["abbygail", "abby", "abagael", "aaren"], r.zrevrangebylex("foo", "[a\xff", "[a")
+      assert_equal ["abbygail", "abby"], r.zrevrangebylex("foo", "[a\xff", "[a", :limit => [0, 2])
+      assert_equal ["abbygail", "abby"], r.zrevrangebylex("foo", "(abb\xff", "(abb")
+      assert_equal ["abbygail"], r.zrevrangebylex("foo", "(abby\xff", "(abby")
+    end
+  end
+
   def test_zcount
     r.zadd "foo", 1, "s1"
     r.zadd "foo", 2, "s2"