Implemented performance improvement to interpolator

lib/paperclip/interpolations.rb

@@ -27,12 +27,9 @@ module Paperclip
     # and the arguments to pass, which are the attachment and style name.
     # You can pass a method name on your record as a symbol, which should turn
     # an interpolation pattern for Paperclip to use.
-    def self.interpolate pattern, *args
-      pattern = args.first.instance.send(pattern) if pattern.kind_of? Symbol
-      all.reverse.inject(pattern) do |result, tag|
-        result.gsub(/:#{tag}/) do |match|
-          send( tag, *args )
-        end
+    def self.interpolate(pattern, *args)
+      pattern.gsub /:([[:word:]]+)/ do
+        Paperclip::Interpolations.respond_to?($1) ? Paperclip::Interpolations.send($1, *args) : ":#{$1}"
       end
     end
 

test/attachment_test.rb

@@ -282,8 +282,8 @@ class AttachmentTest < Test::Unit::TestCase
 
     teardown { @file.close }
 
-    should "make sure that they are interpolated correctly" do
-      assert_equal "1024.omg/1024-bbq/1024what/000/001/024.wtf", @dummy.avatar.path
+    should "make sure that they are interpolated correctly as long non-word characters separate them" do
+      assert_equal "1024.omg/1024-bbq/:idwhat/000/001/024.wtf", @dummy.avatar.path
     end
   end
 

test/interpolations_test.rb

@@ -231,7 +231,6 @@ class InterpolationsTest < Test::Unit::TestCase
   should "call all expected interpolations with the given arguments" do
     Paperclip::Interpolations.expects(:id).with(:attachment, :style).returns(1234)
     Paperclip::Interpolations.expects(:attachment).with(:attachment, :style).returns("attachments")
-    Paperclip::Interpolations.expects(:notreal).never
     value = Paperclip::Interpolations.interpolate(":notreal/:id/:attachment", :attachment, :style)
     assert_equal ":notreal/1234/attachments", value
   end