Add escaping of symbols

lib/liquid/i18n.rb

@@ -24,9 +24,10 @@ module Liquid
 
     private
     def interpolate(name, vars)
-      name.gsub(/:(\w+)/) do
+      name.gsub(/([^\\]):(\w+)/) {
-        vars[$1.to_sym] or raise TranslationError, translate("errors.i18n.undefined_interpolation", :key => $1, :name => name)
+        raise TranslationError, translate("errors.i18n.undefined_interpolation", :key => $1, :name => name) unless vars[$2.to_sym]
-      end
+        "#{$1}#{vars[$2.to_sym]}"
+      }.gsub("\\:", ":")
     end
 
     def deep_fetch_translation(name)

test/liquid/i18n_test.rb

@@ -34,4 +34,12 @@ class I18nTest < Test::Unit::TestCase
   def test_sets_default_path_to_en
     assert_equal I18n::DEFAULT_LOCALE, I18n.new.path
   end
+
+  def test_escaping_of_symbols
+    assert_equal "do replaced! not :gsub", @i18n.send(:interpolate, 
+                            'do :replace not \\:gsub',
+                            {
+                              :replace => "replaced!"
+                            })
+  end
 end