[pmg-devel] [PATCH pmg-docs] docs: document negation and match groups

[Leo Nunner <l.nunner@proxmox.com>]

Signed-off-by: Leo Nunner <l.nunner@proxmox.com>
---
 pmg-mail-filter.adoc | 29 ++++++++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/pmg-mail-filter.adoc b/pmg-mail-filter.adoc
index 3aafe4c..60bb8c0 100644
--- a/pmg-mail-filter.adoc
+++ b/pmg-mail-filter.adoc
@@ -58,9 +58,36 @@ You can also disable a rule completely, which is mostly useful for
 testing and debugging. The 'Factory Defaults' button allows you to
 reset the filter rules.
 
+[[pmg_mailfilter_structure]]
+Rule structure
+--------------
+
+Rules have a predefined structure. A rule contains objects of all
+categories (Action, Who, What, When), which are grouped by their
+respective types.
+
+Matches
+~~~~~~~
+
+The logic behind matches is as follows: all categories need to
+match separately; if a category is empty, it matches automatically.
+As for the objects inside a category, it's enough if only
+one of them matches; if one object matches, the whole category
+matches. Finally, if all categories match, the whole rule counts as
+a match and the defined actions are executed.
+
+This behaviour can be changed by using match groups. Each category
+contains a child item titled 'Match groups'. All objects that are
+added to this group will be evaluated together: the match group only
+evaluates as a match if all objects inside it do.
+
+Objects can also be inverted, so that they only match if their
+criteria are *not* fulfilled. This is indicated via a prefixed
+"NOT" in the object overview.
+
 
 [[pmg_mailfilter_action]]
-'Action' - objects
+'Action' objects
 ------------------
 
 [thumbnail="pmg-gui-mail-filter-actions.png", big=1]
-- 
2.30.2