mirror of
https://github.com/zeek/zeek.git
synced 2025-10-02 22:58:20 +00:00
5c9a7a92a4
Added new sections on operators, statements, and directives. Also improved the documentation on types and attributes by providing more examples and added a chart on the top of each page with links to each type and attribute for easier access to the information.
179 lines
10 KiB
ReStructuredText
179 lines
10 KiB
ReStructuredText
Operators
|
|
=========
|
|
|
|
The Bro scripting language supports the following operators. Note that
|
|
each data type only supports a subset of these operators. For more
|
|
details, see the documentation about the `data types <types.html>`_.
|
|
|
|
Relational operators
|
|
--------------------
|
|
|
|
The relational operators evaluate to type :bro:type:`bool`.
|
|
|
|
+------------------------------+--------------+
|
|
| Name | Syntax |
|
|
+==============================+==============+
|
|
| Equality | *a* == *b* |
|
|
+------------------------------+--------------+
|
|
| Inequality | *a* != *b* |
|
|
+------------------------------+--------------+
|
|
| Less than | *a* < *b* |
|
|
+------------------------------+--------------+
|
|
| Less than or equal | *a* <= *b* |
|
|
+------------------------------+--------------+
|
|
| Greater than | *a* > *b* |
|
|
+------------------------------+--------------+
|
|
| Greater than or equal | *a* >= *b* |
|
|
+------------------------------+--------------+
|
|
|
|
|
|
Logical operators
|
|
-----------------
|
|
|
|
The logical operators require operands of type :bro:type:`bool`, and
|
|
evaluate to type :bro:type:`bool`.
|
|
|
|
+------------------------------+--------------+
|
|
| Name | Syntax |
|
|
+==============================+==============+
|
|
| Logical AND | *a* && *b* |
|
|
+------------------------------+--------------+
|
|
| Logical OR | *a* \|\| *b* |
|
|
+------------------------------+--------------+
|
|
| Logical NOT | ! *a* |
|
|
+------------------------------+--------------+
|
|
|
|
|
|
Arithmetic operators
|
|
--------------------
|
|
|
|
+------------------------------+-------------+-------------------------------+
|
|
| Name | Syntax | Notes |
|
|
+==============================+=============+===============================+
|
|
| Addition | *a* + *b* | If operands are strings, then |
|
|
| | | this performs string |
|
|
| | | concatenation. |
|
|
+------------------------------+-------------+-------------------------------+
|
|
| Subtraction | *a* - *b* | |
|
|
+------------------------------+-------------+-------------------------------+
|
|
| Multiplication | *a* \* *b* | |
|
|
+------------------------------+-------------+-------------------------------+
|
|
| Division | *a* / *b* | |
|
|
+------------------------------+-------------+-------------------------------+
|
|
| Modulo | *a* % *b* | Operand types cannot be |
|
|
| | | double. |
|
|
+------------------------------+-------------+-------------------------------+
|
|
| Unary plus | \+ *a* | |
|
|
+------------------------------+-------------+-------------------------------+
|
|
| Unary minus | \- *a* | |
|
|
+------------------------------+-------------+-------------------------------+
|
|
| Pre-increment | ++ *a* | Operand type cannot be |
|
|
| | | double. |
|
|
+------------------------------+-------------+-------------------------------+
|
|
| Pre-decrement | ``--`` *a* | Operand type cannot be |
|
|
| | | double. |
|
|
+------------------------------+-------------+-------------------------------+
|
|
| Absolute value | \| *a* \| | If operand is string, set, |
|
|
| | | table, or vector, this |
|
|
| | | evaluates to number |
|
|
| | | of elements. |
|
|
+------------------------------+-------------+-------------------------------+
|
|
|
|
|
|
Assignment operators
|
|
--------------------
|
|
|
|
The assignment operators evaluate to the result of the assignment.
|
|
|
|
+------------------------------+-------------+
|
|
| Name | Syntax |
|
|
+==============================+=============+
|
|
| Assignment | *a* = *b* |
|
|
+------------------------------+-------------+
|
|
| Addition assignment | *a* += *b* |
|
|
+------------------------------+-------------+
|
|
| Subtraction assignment | *a* -= *b* |
|
|
+------------------------------+-------------+
|
|
|
|
|
|
Record field operators
|
|
----------------------
|
|
|
|
The record field operators take a :bro:type:`record` as the first operand,
|
|
and a field name as the second operand. For both operators, the specified
|
|
field name must be in the declaration of the record type.
|
|
|
|
+------------------------------+-------------+-------------------------------+
|
|
| Name | Syntax | Notes |
|
|
+==============================+=============+===============================+
|
|
| Field access | *a* $ *b* | |
|
|
+------------------------------+-------------+-------------------------------+
|
|
| Field value existence test | *a* ?$ *b* | Evaluates to type "bool". |
|
|
| | | True if the specified field |
|
|
| | | has been assigned a value, or |
|
|
| | | false if not. |
|
|
+------------------------------+-------------+-------------------------------+
|
|
|
|
|
|
Other operators
|
|
---------------
|
|
|
|
+--------------------------------+-------------------+------------------------+
|
|
| Name | Syntax | Notes |
|
|
+================================+===================+========================+
|
|
| Membership test | *a* in *b* |Evaluates to type |
|
|
| | |"bool". Do not |
|
|
| | |confuse this use of "in"|
|
|
| | |with that used in a |
|
|
| | |:bro:keyword:`for` |
|
|
| | |statement. |
|
|
+--------------------------------+-------------------+------------------------+
|
|
| Non-membership test | *a* !in *b* |This is the logical NOT |
|
|
| | |of the "in" operator. |
|
|
| | |For example: "a !in b" |
|
|
| | |is equivalent to |
|
|
| | |"!(a in b)". |
|
|
+--------------------------------+-------------------+------------------------+
|
|
| Table or vector element access | *a* [ *b* ] |This operator can also |
|
|
| | |be used with a set, but |
|
|
| | |only with the |
|
|
| | |:bro:keyword:`add` or |
|
|
| | |:bro:keyword:`delete` |
|
|
| | |statement. |
|
|
+--------------------------------+-------------------+------------------------+
|
|
| Substring extraction | *a* [ *b* : *c* ] |See the |
|
|
| | |:bro:type:`string` type |
|
|
| | |for more details. |
|
|
+--------------------------------+-------------------+------------------------+
|
|
| Create a deep copy | copy ( *a* ) |This is relevant only |
|
|
| | |for data types that are |
|
|
| | |assigned by reference, |
|
|
| | |such as "vector", "set",|
|
|
| | |"table", and "record". |
|
|
+--------------------------------+-------------------+------------------------+
|
|
| Module namespace access | *a* \:\: *b* |The first operand is the|
|
|
| | |module name, and the |
|
|
| | |second operand is an |
|
|
| | |identifier that refers |
|
|
| | |to a global variable, |
|
|
| | |enumeration constant, or|
|
|
| | |user-defined type that |
|
|
| | |was exported from the |
|
|
| | |module. |
|
|
+--------------------------------+-------------------+------------------------+
|
|
| Conditional | *a* ? *b* : *c* |The first operand must |
|
|
| | |evaluate to a "bool" |
|
|
| | |type. If true, then the|
|
|
| | |second expression is |
|
|
| | |evaluated and is the |
|
|
| | |result of the entire |
|
|
| | |expression. Otherwise, |
|
|
| | |the third expression is |
|
|
| | |evaluated and is the |
|
|
| | |result of the entire |
|
|
| | |expression. The types of|
|
|
| | |the second and third |
|
|
| | |operands must be |
|
|
| | |compatible. |
|
|
+--------------------------------+-------------------+------------------------+
|
|
|