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.

Relational operators

The relational operators evaluate to 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 bool, and evaluate to type bool.

Name	Syntax
Logical AND	a && b
Logical OR	a || b
Logical NOT	! a

Arithmetic operators

Name	Syntax	Notes
Addition	a + b	For string operands, this performs string concatenation.
Subtraction	a - b
Multiplication	a * b
Division	a / b	For int or 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 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 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 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 add or delete statement.
Substring extraction	a [ b : c ]	See the 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 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.