From 5db1695694e1cbf12892d5dd67c7773282a669af Mon Sep 17 00:00:00 2001
From: Derrick Reimer <derrickreimer@gmail.com>
Date: Wed, 9 Oct 2013 16:07:32 -0700
Subject: [PATCH] Add default filter to standard filters

---
 lib/liquid/standardfilters.rb       | 5 +++++
 test/liquid/standard_filter_test.rb | 9 +++++++++
 2 files changed, 14 insertions(+)

diff --git a/lib/liquid/standardfilters.rb b/lib/liquid/standardfilters.rb
index 718a8d9..c938f3a 100644
--- a/lib/liquid/standardfilters.rb
+++ b/lib/liquid/standardfilters.rb
@@ -245,6 +245,11 @@ module Liquid
       apply_operation(input, operand, :%)
     end
 
+    def default(input, default_value = "")
+      is_blank = input.respond_to?(:empty?) ? input.empty? : !input
+      is_blank ? default_value : input
+    end
+
     private
 
     def flatten_if_necessary(input)
diff --git a/test/liquid/standard_filter_test.rb b/test/liquid/standard_filter_test.rb
index fc1a3cb..91c219d 100644
--- a/test/liquid/standard_filter_test.rb
+++ b/test/liquid/standard_filter_test.rb
@@ -274,6 +274,15 @@ class StandardFiltersTest < Test::Unit::TestCase
     assert_template_result('abc',"{{ a | prepend: b}}",assigns)
   end
 
+  def test_default
+    assert_equal "foo", @filters.default("foo", "bar")
+    assert_equal "bar", @filters.default(nil, "bar")
+    assert_equal "bar", @filters.default("", "bar")
+    assert_equal "bar", @filters.default(false, "bar")
+    assert_equal "bar", @filters.default([], "bar")
+    assert_equal "bar", @filters.default({}, "bar")
+  end
+
   def test_cannot_access_private_methods
     assert_template_result('a',"{{ 'a' | to_number }}")
   end