Operators
Just as a sentence means nothing without a verb, anything you write in RuLa means nothing without operators. They make it possible for a variable to be defined, for a condition to work and for a rule to make sense.
The table below lists all available operators in alphabetical order, with a brief description. For a more extensive description of each individual operator, plus examples, click on it or visit the sub-pages in the menu on the left.

Available Operators and Keywords

Operator
Category
Description
=
Boolean
Compares. Evaluates to either true or false, delivering different outcomes.
!=
Boolean
Compares, true for 'is not equal to'.
>
Boolean
Compares, true for 'greater than'.
>=
Boolean
Compares, true for 'equal to or greater than'.
<
Boolean
Compares, true for 'less than'.
<=
Boolean
Compares, true for 'equal to or less than'.
:=
Special
Assignment, which can have any kind of expression on the right side of the operator.
+, -, /, *, %
Perform basic mathematical calculations.
[ , ]
List
Creates a new list from single values, allowing other list operators to perform actions on the new list.
ADD_YEARS
Date
Takes a date and adds a specified number of years to it.
AFTER
Date
Takes two dates, and checks if the first one comes after the second one.
Date
Takes two dates, and checks if the first one comes after, or is the same as, the second one.
ALL
List
Evaluates if all values in a list are true.
and
Boolean
Sets as condition that both expressions have to be true to have the entire expression evaluate to 'true'.
and then
Boolean
Similar as above, but when using 'and then', the second question is only asked when the first evaluates to 'true'.
AVG
Calculates the average value.
Known
Calculates the average of available values.
BEFORE
Date
Takes two dates, and checks if the first one comes before the second one.
Date
Takes two dates, and checks if the first one comes before, or is the same as, the second one.
String
Accesses the calculated name of an instance.
CEIL
Returns the value of the given parameter, rounded up to a whole number.
CONCAT
String
Combines two values into one new value, specifying what should separate the two.
contains
List
Goes over a list, which is given on the left of the operator. Evaluates to 'true' if the single value on the right is present in the given list.
List
Expressions with this operator will only evaluate to 'true' if all values from the list on the right side are present in the list on the left side.
List
Going over a list, given on the left side of the operator, this operator has the expression evaluate to true if any value from that list is present in a list or the single value given on the right side.
COUNT
List
Returns the number of occurrences of the given parameter.
ensure
Special
Makes sure a case contains at least, for example, 1 Person. (replaces create)
List
Returns the first element from a list.
FLOOR
Returns the value of the given parameter, rounded down to a whole number.
get_attr
Special
Gives access to named properties of an instance using expressions.
Special
Returns specific information on an instance's properties.
in
List
Checks if a value is present in a taxonomy.
instances
Special
Returns all instances of the given type(s) living on the platform.
is
Special
Basic assignment of a variable.
JOIN
String
Combines a list of values into one new value by appending them.
known
Known
Sets a condition for when a property is not unknown.
Known
Builds a list of only the values that are available out of all the values it is given.
MAP
List
Performs the same action on each individual value in a list.
MAX
Returns the highest value.
Known
Returns the highest out of available values.
MIN
Returns the lowest value.
Known
Returns the lowest out of available values.
not
Boolean
A negation.
not in
List
Evaluates to true if the given value is absent from the specified taxonomy.
NOW
Date
Current date and time.
ontology
Special
Sets a condition based on the type of ontology.
optional
Special
The rule can accept, but will not require, for example, a third person.
or
Boolean
When just one of the two given expressions is true, the entire expression evaluates to 'true'.
or else
Boolean
Similar to above, but the second question is only asked if the first has been answered.
roles
Special
Sets a condition based on role(s).
ROUND
Returns the value of the given parameter, rounded to a whole number.
self
Special
Refers to the current instance where you use it.
SNEAKY
Known
Wrapping an expression with SNEAKYhas the system ignore the expression, if the information used in it is not available.
SOME
List
Evaluates if any value in a list is true.
Date
Takes a date and subtracts a specified number of years to it.
SUM
Adds up numbers.
Known
Adds available numbers.
Multiplies values in one list with values on the same index in another list. Returns the sum of the multiplications.
UNION
List
Combines the elements of two sets into one single set.
Known
Creates a combined list of the available values and lists out of all values and lists you provide.
unknown
Known
Sets a condition for when a property is unknown.
YEARS_AGO
Date
Calculates the number of years since a given date.
Last modified 6mo ago