diff --git a/Slang/slang.js b/Slang/slang.js
index ea36375..1fcde7e 100755
--- a/Slang/slang.js
+++ b/Slang/slang.js
@@ -849,6 +849,20 @@ var BOOTSTRAP = [
 'infix: >= ge',
 '',
 '',
+'-- swap stack and code untill the block finishes and consumes it\'s arguments',
+'-- then swap them back...',
+':: prefix: ( | op word -- | ) [',
+'	[',
+'		-- format the word definition...',
+'		--		NAME WORD	->	:: NAME WORD',
+'		s2b \\ :: -2 before b2s',
+'',
+'		-- the code template',
+'		[ \\ _flip \\ exec \\ WORD _flip ] clone',
+'			swap WORD replace',
+'			3 0 _swapN',
+'	] \\ exec 2 2 _swapN ]',
+'',
 '',
 '-- Tests and examples...',
 '',