--- /dev/null
+# Rspamd composite rules
+
+Rspamd composites are used to combine rules and create more complex rules.
+Composite rules are defined by `composite` keys. The value of this key should be
+an object that defines composite's name and value, which is the combination of rules
+in a joint expression.
+
+For example, you can define a composite that is added when two of symbols are found:
+
+~~~nginx
+composite {
+ name = "TEST_COMPOSITE";
+ expression = "SYMBOL1 and SYMBOL2";
+}
+~~~
+
+In this case, if a message has `SYMBOL1` and `SYMBOL2` simultaneously then they are replaced by
+symbol `TEST_COMPOSITE`. The weights of `SYMBOL1` and `SYMBOL2` are substracted from the metric
+accordingly.
+
+## Composite expression
+
+You can use the following operations in a composite expression:
+
+* `AND` `&` - matches true only if both of operands are true
+* `OR` `|` - matches true if any of operands are true
+* `NOT` `!` - matches true if operand is false
+
+You also can use braces to define priorities. Otherwise operators are evaluated from left to right.
+For example:
+
+~~~nginx
+composite {
+ name = "TEST";
+ expression = "SYMBOL1 and SYMBOL2 and ( not SYMBOL3 | not SYMBOL4 | not SYMBOL5 )";
+}
+~~~
+
+Composite rule can include other composites in the body. There is no restriction of definition order:
+~~~nginx
+composite {
+ name = "TEST1";
+ expression = "SYMBOL1 AND TEST2";
+}
+composite {
+ name = "TEST2";
+ expression = "SYMBOL2 OR NOT SYMBOL3";
+}
+~~~
+
+Composites should not be recursive and it is normally detected by rspamd.
+
+## Composite weights rules
+Composites can leave the symbols in a metric or leave their weights. That could be used to create
+non-captive composites.
+For example, you have symbol `A` and `B` with weights `W_a` and `W_b` and a composite `C` with weight `W_c`.
+
+* If `C` is `A & B` then if rule `A` and rule `B` matched then these symbols are *removed* and their weights are removed as well, leading to a single symbol `C` with weight `W_c`.
+* If `C` is `-A & B`, then rule `A` is preserved, but the symbol `C` is inserted. The weight of `A` is preserved as well, so the total weight of `-A & B` will be `W_a + W_c`.
+* If `C` is `~A & B`, then rule `A` is *removed* but its weight is *preserved*, leading to a single symbol `C` with weight `W_a + W_c`
+
this [document](ucl.md). Rspamd defines several variables and macros to extend
UCL functionality.
+## Table of Contents
+
+* [Options](options.md)
+* [Logging](logging.md)
+* [Metrics](metrics.md)
+* [Composites](composites.md)
+* [User settings](settings.md)
+* [Statistic configuration](statistic.md)
+* [Workers](../workers/index.md)
+* [Modules](../modules/index.md)
+
## Rspamd variables
- *CONFDIR*: configuration directory for rspamd, it is $PREFIX/etc/rspamd/
section specifies rspamd workers settings. [Composites](composites.md) is an utility
section that describes composite symbols. Statistical filters are defined in
[statistic](statistic.md) section. Rspamd stores modules configuration (for both lua
-and internal modules) in [modules](modules.md) section while modules itself are
+and internal modules) in [modules](../modules/index.md) section while modules itself are
loaded from the following portion of configuration:
~~~nginx
This configuration is not intended to be changed by user, but you can include your
own configuration in further. To redefine symbols weight and actions rspamd encourages
-to use [dynamic configuration](dynamic_conf.md). Nevertheless, rspamd installation
+to use [dynamic configuration](settings.md). Nevertheless, rspamd installation
script will never rewrite user's configuration if it exists already. So please
read ChangeLog carefully if you upgrade rspamd to a new version for all incompatible
-configuration changes.
\ No newline at end of file
+configuration changes.