Fixing a string interpolation bug. Thanks, Toons!

git-svn-id: svn://hamptoncatlin.com/haml/trunk@580 7063305b-7217-0410-af8c-cdc13e5119b9

lib/haml/engine.rb

@@ -887,12 +887,12 @@ END
       if first.nil?
         return str.dump
       elsif first != 0
-        first -= 1
+        first += 1
       end
 
       last = str.rindex '}'
 
-      interpolation = str.slice!(first, last + 1)
+      interpolation = str.slice!(first, last - first)
       str.insert(first, "_haml_interpolation")
 
       str = str.dump

test/haml/engine_test.rb

@@ -70,6 +70,11 @@ class EngineTest < Test::Unit::TestCase
     assert_equal("<p>\n  Hello World\n</p>\n", render("%p\n  == Hello \#{who}", :locals => {:who => 'World'}))
   end
 
+  def test_double_equals_in_the_middle_of_a_string
+    assert_equal("\"title 'Title'. \"\n",
+                 render("== \"title '\#{\"Title\"}'. \""))
+  end
+
   # Options tests
 
   def test_stop_eval