+* The dynamic value of an application-specific context field is read by
+ prefixing its name with `$app.` (follows the format used to add such a
+ context field with the man:lttng-add-context(1) command).
++
+When the expression's application-specific context field does not exist,
+the whole filter expression evaluates to false.
++
+Example: `$app.server:cur_user`.
+
+The following precedence table shows the operators which are supported
+in a filter expression. In this table, the highest precedence is 1.
+Parentheses are supported to bypass the default order.
+
+IMPORTANT: Unlike the C language, the `lttng enable-event` filter
+expression syntax's bitwise AND and OR operators (`&` and `|`) take
+precedence over relational operators (`<`, `<=`, `>`, `>=`, `==`, and
+`!=`). This means the filter expression `2 & 2 == 2` is true while the
+equivalent C expression is false.
+
+[options="header"]
+|===
+|Precedence |Operator |Description |Associativity
+|1 |`-` |Unary minus |Right-to-left
+|1 |`+` |Unary plus |Right-to-left
+|1 |`!` |Logical NOT |Right-to-left
+|1 |`~` |Bitwise NOT |Right-to-left
+|2 |`<<` |Bitwise left shift |Left-to-right
+|2 |`>>` |Bitwise right shift |Left-to-right
+|3 |`&` |Bitwise AND |Left-to-right
+|4 |`^` |Bitwise XOR |Left-to-right
+|5 |`\|` |Bitwise OR |Left-to-right
+|6 |`<` |Less than |Left-to-right
+|6 |`<=` |Less than or equal to |Left-to-right
+|6 |`>` |Greater than |Left-to-right
+|6 |`>=` |Greater than or equal to |Left-to-right
+|7 |`==` |Equal to |Left-to-right
+|7 |`!=` |Not equal to |Left-to-right
+|8 |`&&` |Logical AND |Left-to-right
+|9 |`\|\|` |Logical OR |Left-to-right
+|===
+
+The arithmetic operators are :not: supported.
+
+All integer constants and fields are first casted to signed 64-bit
+integers. The representation of negative integers is two's complement.
+This means that, for example, the signed 8-bit integer field 0xff (-1)
+becomes 0xffffffffffffffff (still -1) once casted.
+
+Before a bitwise operator is applied, all its operands are casted to
+unsigned 64-bit integers, and the result is casted back to a signed
+64-bit integer. For the bitwise NOT operator, it is the equivalent of
+this C expression:
+
+[source,c]
+----
+(int64_t) ~((uint64_t) val)
+----