1 files changed, 27 insertions, 2 deletions
diff --git a/lib/reline.rb b/lib/reline.rb
index 656fab2fea..0c65d8738a 100644
--- a/lib/reline.rb
+++ b/lib/reline.rb
@@ -26,6 +26,10 @@ module Reline
   @@ambiguous_width = nil
 
   HISTORY = Class.new(Array) {
+    def initialize(config)
+      @config = config
+    end
+
     def to_s
       'HISTORY'
     end
@@ -45,21 +49,42 @@ module Reline
       super(index, String.new(val, encoding: Encoding::default_external))
     end
 
+    def concat(*val)
+      val.each do |v|
+        push(*v)
+      end
+    end
+
     def push(*val)
+      diff = size + val.size - @config.history_size
+      if diff > 0
+        if diff <= size
+          shift(diff)
+        else
+          diff -= size
+          clear
+          val.shift(diff)
+        end
+      end
       super(*(val.map{ |v| String.new(v, encoding: Encoding::default_external) }))
     end
 
     def <<(val)
+      shift if size + 1 > @config.history_size
       super(String.new(val, encoding: Encoding::default_external))
     end
 
     private def check_index(index)
       index += size if index < 0
-      raise RangeError.new("index=<#{index}>") if index < -@@config.history_size or @@config.history_size < index
+      raise RangeError.new("index=<#{index}>") if index < -@config.history_size or @config.history_size < index
       raise IndexError.new("index=<#{index}>") if index < 0 or size <= index
       index
     end
-  }.new
+
+    private def set_config(config)
+      @config = config
+    end
+  }.new(@@config)
 
   @@completion_append_character = nil
   def self.completion_append_character