agreed. reconstructing the semantics of the rules is a challenge, e.g,
consider a UI where there's a simple rule for matching mailing lists.
this would probably be a macro with lots of heuristics, checking List-Id
but also Sender and stuff like that. when loaded into a different
client it should of course handle this, but it may present the rule as a
sequence of tests rather than a single macro. IMHO, it's not realistic
to standardise these things, since we will never catch all the
use-cases.
for the case of temporarily disabling a rule, I think the most obvious
method is a simple
if false { }
around the block. that construct can hardly be used for anything else.
using comments is bad, since comments should be truly freeform and
without meaning.