.

Gemfile

@@ -8,6 +8,7 @@ end
 gemspec
 
 gem "base64"
+gem "webrick"
 
 group :benchmark, :test do
   gem 'benchmark-ips'

example/server/example_servlet.rb

@@ -20,7 +20,7 @@ def paragraph(p)
 
 class Servlet < LiquidServlet
   def index
-    { 'date' => Time.now }
+    { 'date' => Time.now, 'products' => products_list }
   end
 
   def products
@@ -29,11 +29,42 @@ def products
 
   private
 
+  class Name < Liquid::Drop
+    attr_reader :raw, :origin
+
+    def initialize(raw, origin)
+      super
+      @raw = raw
+      @origin = origin
+    end
+  end
+
+  class Price < Liquid::Drop
+    attr_reader :value, :unit
+
+    def initialize(value, unit = 'USD')
+      super
+      @value = value
+      @unit = unit
+    end
+  end
+
+  class Product < Liquid::Drop
+    attr_reader :name, :price, :description
+
+    def initialize(name, origin, price, description)
+      super
+      @name = Name.new(name, origin)
+      @price = Price.new(price)
+      @description = description
+    end
+  end
+
   def products_list
     [
-      { 'name' => 'Arbor Draft', 'price' => 39900, 'description' => 'the *arbor draft* is a excellent product' },
-      { 'name' => 'Arbor Element', 'price' => 40000, 'description' => 'the *arbor element* rocks for freestyling' },
-      { 'name' => 'Arbor Diamond', 'price' => 59900, 'description' => 'the *arbor diamond* is a made up product because im obsessed with arbor and have no creativity' }
+      Product.new('Draft', 'Arbor', 39900, 'the *arbor draft* is a excellent product'),
+      Product.new('Element', 'Arbor', 40000, 'the *arbor element* rocks for freestyling'),
+      Product.new('Diamond', 'Arbor', 59900, 'the *arbor diamond* is a made up product because im obsessed with arbor and have no creativity')
     ]
   end
 

example/server/templates/index.liquid

@@ -2,5 +2,11 @@
 
 <p>It is {{date}}</p>
 
+<br>
 
-<p>Check out the <a href="/products">Products</a> screen </p>
+{{ products.size }}
+
+
+<br><br>
+
+{{ products | sum: 'price.value' }}

lib/liquid/drop.rb

@@ -62,6 +62,19 @@ def to_s
 
     alias_method :[], :invoke_drop
 
+    def dig(keys)
+      if self.class.invokable?(keys)
+        # For backward compatibility - historically some drops may have
+        # properties containing dots in their names (e.g. "foo.bar").
+        # We first attempt to look up the exact key before falling
+        # back to treating dots as nested property access.
+        return invoke_drop(keys)
+      end
+
+      keys = keys.to_s.split('.') unless keys.is_a?(Array)
+      keys.inject(self) { |obj, key| obj.respond_to?(:[]) ? obj[key] : nil }
+    end
+
     # Check for method existence without invoking respond_to?, which creates symbols
     def self.invokable?(method_name)
       invokable_methods.include?(method_name.to_s)

lib/liquid/standardfilters.rb

@@ -376,6 +376,12 @@ def sort(input, property = nil)
         ary.sort do |a, b|
           nil_safe_compare(a, b)
         end
+      elsif ary.all? { |el| el.respond_to?(:dig) }
+        begin
+          ary.sort { |a, b| nil_safe_compare(a.dig(property), b.dig(property)) }
+        rescue TypeError
+          raise_property_error(property)
+        end
       elsif ary.all? { |el| el.respond_to?(:[]) }
         begin
           ary.sort { |a, b| nil_safe_compare(a[property], b[property]) }
@@ -405,6 +411,12 @@ def sort_natural(input, property = nil)
         ary.sort do |a, b|
           nil_safe_casecmp(a, b)
         end
+      elsif ary.all? { |el| el.respond_to?(:dig) }
+        begin
+          ary.sort { |a, b| nil_safe_casecmp(a.dig(property), b.dig(property)) }
+        rescue TypeError
+          raise_property_error(property)
+        end
       elsif ary.all? { |el| el.respond_to?(:[]) }
         begin
           ary.sort { |a, b| nil_safe_casecmp(a[property], b[property]) }
@@ -495,7 +507,11 @@ def uniq(input, property = nil)
         []
       else
         ary.uniq do |item|
-          item[property]
+          if item.respond_to?(:dig)
+            item.dig(property)
+          else
+            item[property]
+          end
         rescue TypeError
           raise_property_error(property)
         rescue NoMethodError
@@ -530,6 +546,9 @@ def map(input, property)
 
         if property == "to_liquid"
           e
+        elsif e.respond_to?(:dig)
+          r = e.dig(property)
+          r.is_a?(Proc) ? r.call : r
         elsif e.respond_to?(:[])
           r = e[property]
           r.is_a?(Proc) ? r.call : r
@@ -555,7 +574,11 @@ def compact(input, property = nil)
         []
       else
         ary.reject do |item|
-          item[property].nil?
+          if item.respond_to?(:dig)
+            item.dig(property).nil?
+          else
+            item[property].nil?
+          end
         rescue TypeError
           raise_property_error(property)
         rescue NoMethodError
@@ -928,6 +951,8 @@ def sum(input, property = nil)
       values_for_sum = ary.map do |item|
         if property.nil?
           item
+        elsif item.respond_to?(:dig)
+          item.dig(property)
         elsif item.respond_to?(:[])
           item[property]
         else
@@ -955,7 +980,13 @@ def filter_array(input, property, target_value, method)
 
       ary.public_send(method) do |item|
         if target_value.nil?
-          item[property]
+          if item.respond_to?(:dig)
+            item.dig(property)
+          else
+            item[property]
+          end
+        elsif item.respond_to?(:dig)
+          item.dig(property) == target_value
         else
           item[property] == target_value
         end