> by the fact that some (but not all!) meta headers are idempotent.
>
> --[[smcv]]
+
+>> Thanks for your comment. Tonight I had a go at implementing the syntax
+>> you propose here. I decided the simplest thing to do might be for the scan
+>> subroutine to convert any hashes found in the meta_defaults list into calls
+>> to the preprocess routine. I've got a bit stuck trying to convert a hash to
+>> a named parameter list (or just a subroutine parameter list that is). I may
+>> try to look again in the morning (brain a bit sleepy)
+>>
+>> ...and on writing this comment I see your second suggestion was essentially
+>> to do exactly that :) -- [[Jon]]