mirror of
https://github.com/zeek/zeek.git
synced 2025-10-02 22:58:20 +00:00
175ff9cf2d
* origin/topic/dnthayer/langref: Minor improvements to script language reference docs Add more script language reference documentation Split the types and attributes reference doc into two docs Wow, this is great! BIT-1269 #merged
191 lines
11 KiB
ReStructuredText
191 lines
11 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* | For :bro:type:`string` |
|
|
| | | operands, this performs |
|
|
| | | string concatenation. |
|
|
+------------------------------+-------------+-------------------------------+
|
|
| Subtraction | *a* - *b* | |
|
|
+------------------------------+-------------+-------------------------------+
|
|
| Multiplication | *a* \* *b* | |
|
|
+------------------------------+-------------+-------------------------------+
|
|
| Division | *a* / *b* | For :bro:type:`int` or |
|
|
| | | :bro:type:`count` operands, |
|
|
| | | the fractional part of the |
|
|
| | | result is dropped. |
|
|
+------------------------------+-------------+-------------------------------+
|
|
| 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 |
|
|
| | | :bro:type:`string`, |
|
|
| | | :bro:type:`set`, |
|
|
| | | :bro:type:`table`, or |
|
|
| | | :bro:type:`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 |
|
|
| | | :bro: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 |
|
|
| | |:bro: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 |
|
|
| | |:bro:type:`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 |
|
|
| | |:bro:type:`vector`, |
|
|
| | |:bro:type:`set`, |
|
|
| | |:bro:type:`table`, |
|
|
| | |and :bro:type:`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 type |
|
|
| | |:bro:type:`bool`. |
|
|
| | |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. |
|
|
+--------------------------------+-------------------+------------------------+
|
|
|