A neat response to the same problem posted yesterday:<p><a href="http:&#x2F;&#x2F;akkartik.name&#x2F;post&#x2F;wart-layers" rel="nofollow">http:&#x2F;&#x2F;akkartik.name&#x2F;post&#x2F;wart-layers</a><p>Basically, layers with numbers and preprocessor directives to inject (tangle) code in the proper places without worrying too much about language abstractions.