added break and continue tags

lib/liquid/errors.rb

@@ -8,4 +8,9 @@ module Liquid
   class StandardError < Error; end
   class SyntaxError < Error; end
   class StackLevelError < Error; end
+
+
+  class Interrupt < Error; end
+  class BreakInterrupt < Interrupt; end
+  class ContinueInterrupt < Interrupt; end
 end

lib/liquid/tags/break.rb

@@ -0,0 +1,24 @@
+module Liquid
+
+  # Break tag to be used to break out of a for loop.
+  #
+  # == Basic Usage:
+  #    {% for item in collection %}
+  #      {% if item.condition %}
+  #        {% break %}
+  #      {% endif %}
+  #    {% endfor %}
+  # 
+  class Break < Tag
+
+    ##
+    # Add an interrupt to context errors so a for loop can check
+    # for interrupts. 
+    def render(context)
+      context.handle_error(BreakInterrupt.new)
+    end
+    
+  end
+
+  Template.register_tag('break', Break)
+end

lib/liquid/tags/continue.rb

@@ -0,0 +1,24 @@
+module Liquid
+
+  # Continue tag to be used to break out of a for loop.
+  #
+  # == Basic Usage:
+  #    {% for item in collection %}
+  #      {% if item.condition %}
+  #        {% continue %}
+  #      {% endif %}
+  #    {% endfor %}
+  # 
+  class Continue < Tag
+
+    ##
+    # Add an interrupt to context errors so a for loop can check
+    # for interrupts. 
+    def render(context)
+      context.handle_error(ContinueInterrupt.new)
+    end
+    
+  end
+
+  Template.register_tag('continue', Continue)
+end

lib/liquid/tags/for.rb

@@ -114,7 +114,19 @@ module Liquid
             'first'   => (index == 0),
             'last'    => (index == length - 1) }
 
-          result << render_all(@for_block, context)
+          rendered = render_all(@for_block, context)
+
+          if context.errors.last.is_a? BreakInterrupt
+            context.errors.pop
+            break
+          end
+
+          if context.errors.last.is_a? ContinueInterrupt
+            context.errors.pop 
+            next
+          end
+
+          result << rendered
         end
       end
       result     

test/liquid/tags/for_tag_test.rb

@@ -168,6 +168,19 @@ HERE
       assert_template_result(expected,markup,assigns)
   end
 
+  def test_break
+    assigns = {'array' => {'items' => [1,2,3,4,5,6,7,8,9,10]}}
+    markup = '{% for i in array.items %}{{ i }}{% if i > 3 %}{% break %}{% endif %}{% endfor %}'
+    expected = "123"
+    assert_template_result(expected,markup,assigns)
+  end
+
+  def test_continue
+    assigns = {'array' => {'items' => [1,2,3,4,5]}}
+    markup = '{% for i in array.items %}{% if i == 3 %}{% continue %}{% else %}{{ i }}{% endif %}{% endfor %}'
+    expected = "1245"
+    assert_template_result(expected,markup,assigns)
+  end
 
   def test_for_tag_string
     # ruby 1.8.7 "String".each => Enumerator with single "String" element.