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Merge remote-tracking branch 'origin/topic/dnthayer/langref'

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* 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

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Robin Sommer 2014-10-07 14:18:08 -07:00
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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. |
+--------------------------------+-------------------+------------------------+