diff --git a/Slang/slang.js b/Slang/slang.js
index dc39bd6..0655057 100755
--- a/Slang/slang.js
+++ b/Slang/slang.js
@@ -747,18 +747,30 @@ var BOOTSTRAP = [
 '-- push element to tail of block...',
 ':: push ( b e -- b ) [ swap len rot swap tor to ]',
 '',
+'-- Replace a pattern (p) in block with value (v)...',
+'-- NOTE: this will replace ALL patterns...',
+':: replace ( l v p -- l ) [',
+'	swap',
+'	[ . \\ VALUE ] clone',
+'		swap 2 to',
+'		rot',
+'	-- XXX for some reason ? without else messes things up...',
+'	[ dup \\ PATTERN eq ? VALUE_BLOCK else [ ] ] clone',
+'		swap 2 to', 
+'		tor 5 to',
+'	map ]',
+'',
 '-- Filter the block via a condition...',
 '--',
 '-- the condition block must have the folowing stack effect: elem -- bool',
 ':: filter ( b c -- b ) [',
 '	-- prepare the condition...',
 '	[ dup \\ TEST exec ] clone',
-'		swap 2 to',
+'		swap TEST replace',
 '	-- prepare the template...',
 '	[ TEST ? [  ] else [ . ] ] clone',
-'		swap 0 to',
-'			-- do the filtering',
-'			map ]',
+'		swap TEST replace',
+'	map ]',
 '',
 '-- Create a block containing a range of numbers form 0 to n-1...',
 ':: range ( n -- b ) [',
@@ -807,7 +819,7 @@ var BOOTSTRAP = [
 '				-- exec the right side and arragne the args for WORD...',
 '				\\ exec \\ WORD 2 1 _swapN ] clone',
 '			-- get the WORD and insert it into the template above (opsition 8)...',
-'			swap 8 to',
+'			swap WORD replace',
 '',
 '		-- push to code / run',
 '		3 0 _swapN ',