Added a parallel to ActionView's capture method (Haml::Helpers#capture_haml).

git-svn-id: svn://hamptoncatlin.com/haml/branches/edge@161 7063305b-7217-0410-af8c-cdc13e5119b9

lib/haml/helpers.rb

@@ -60,6 +60,22 @@ module Haml
       buffer.tabulation -= i
     end
     
+    # Captures the result of the given block of Haml code and returns
+    # them as a string. For example, after the following,
+    #
+    #   - foo = capture_haml(13) do |a|
+    #     %p= a
+    #
+    # the local variable <tt>foo</tt> would be assigned to "<p>13</p>\n".
+    def capture_haml(*args, &block)
+      buffer_buffer = buffer.buffer
+      position = buffer_buffer.length
+      
+      block.call(*args)
+      
+      buffer_buffer.slice!(position..-1)
+    end
+
     # Gets a reference to the current Haml::Buffer object.
     def buffer # :nodoc:
       @haml_stack[-1]

test/helper_test.rb

@@ -95,5 +95,9 @@ class HelperTest < Test::Unit::TestCase
     old_rails = "" 
     assert(result == new_rails || result == old_rails)
   end
+  
+  def test_capture_haml
+    assert_equal("\"<p>13</p>\\n\"\n", render("- foo = capture_haml(13) do |a|\n  %p= a\n= foo.dump"))
+  end
 end
 

test/results/helpers.xhtml

@@ -27,7 +27,11 @@
   <p>
     reeeeeeeeeeeeeeeeeeeeeeeeeeeeeeally loooooooooooooooooong
   </p>
+<div>
+  <h1>Big!</h1>
+  <p>Small</p>
+  <!-- Invisible -->
+</div>
 <p>baz</p>
                     <p>boom</p>
 foo
-

test/templates/helpers.haml

@@ -12,8 +12,12 @@
 - tab_up
 %p reeeeeeeeeeeeeeeeeeeeeeeeeeeeeeally loooooooooooooooooong
 - tab_down
+= capture_haml do
+  %div
+    %h1 Big!
+    %p Small
+    / Invisible
 %p baz
 - buffer.tabulation = 10
 %p boom
 - concat "foo\n"
-