Hi!
From RFC3028:
2.5. Tests
<snip>
Tests MUST NOT have side effects. That is, a test cannot affect the
state of the filter or message. No tests in this specification have
side effects, and side effects are forbidden in extension tests as
well.
The rationale for this is that tests with side effects impair
readability and maintainability and are difficult to represent in a
graphic interface for generating scripts. Side effects are confined
to actions where they are clearer.
So the variables extension, as it stands, violates this MUST, since the
numerical variables are set as a side-effect of a test with :matches
match type. :-(
What now?
We have to reach consensus to revise the specification and remove the MUST.
Ned