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 operators below are grouped by category, and listed alphabetically within each category. 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.

Boolean Operators

Operator	Description
=, !=, <, <=, >, >=	Perform basic comparisons. Evaluate to either true or false.
and	Sets as condition that both expressions have to be true to have the entire expression evaluate to 'true'.
and then	Similar as above, but when using 'and then', the second question is only asked when the first evaluates to 'true'.
falsy (new in Atfinity 17)	Coerces a value to a boolean, returning true only for false, 0, "0", or "false".
matches (=~)	Checks if a string matches a regular expression.
not	A negation.
or	When just one of the two given expressions is true, the entire expression evaluates to 'true'.
or else	Similar to above, but the second question is only asked if the first has been answered.
truthy (new in Atfinity 17)	Coerces a value to a boolean, returning true only for true, 1, "1", or "true".

Mathematical Operators

Operator	Description
+, -, /, *, %	Perform basic mathematical calculations.
AVG	Calculates the average value.
CEIL	Returns the value of the given parameter, rounded up to a whole number.
CLAMP	Clamps a numeric value between a minimum and maximum.
COMB	Returns the number of ways to choose k items from n items (n choose k).
FLOOR	Returns the value of the given parameter, rounded down to a whole number.
MAX	Returns the highest value.
MIN	Returns the lowest value.
ROUND	Returns the value of the given parameter, rounded to a whole number.
SQRT	Returns the square root of a number.
SUM	Adds up numbers.
SUM_PRODUCT	Multiplies values in one list with values on the same index in another list. Returns the sum of the multiplications.

Date Operators

Operator	Description
ADD_DAYS	Takes a date and adds a specified number of days to it.
ADD_MONTHS	Takes a date and adds a specified number of months to it.
ADD_WEEKDAYS	Takes a date and adds a specified number of weekdays (Mon–Fri), skipping weekends.
ADD_YEARS	Takes a date and adds a specified number of years to it.
AFTER	Takes two dates, and checks if the first one comes after the second one.
AFTER_EQUAL	Takes two dates, and checks if the first one comes after, or is the same as, the second one.
BEFORE	Takes two dates, and checks if the first one comes before the second one.
BEFORE_EQUAL	Takes two dates, and checks if the first one comes before, or is the same as, the second one.
DATE_EQUAL	Returns true if two dates refer to the same calendar date, ignoring time.
DATETIME_EQUAL	Returns true if two datetime values refer to the exact same point in time.
DAYS_AGO	Returns the number of days since a given date.
DAYS_BETWEEN	Returns the number of days between two dates.
DAYS_SPENT_IN_STATE	Returns the number of days the current case has spent in a given state.
FORMAT_DATE	Formats a date as a human-readable string using a format pattern.
FORMAT_DATETIME	Formats a datetime value as a human-readable string using a format pattern.
HOURS_BETWEEN	Returns the number of hours between two datetime values.
HOURS_SPENT_IN_STATE	Returns the number of hours the current case has spent in a given state.
IS_DATE	Returns true if the given value can be parsed as a valid date or datetime.
IS_WEEKDAY	Returns true if the date falls on a Monday through Friday.
IS_WEEKEND	Returns true if the date falls on a Saturday or Sunday.
MONTHS_AGO	Returns the number of months since a given date.
NOW	Current date and time.
QUARTER_OF	Returns the quarter (1–4) of the year for a given date.
SUBTRACT_YEARS	Takes a date and subtracts a specified number of years from it.
TODAY	The current date.
WEEKDAYS	Returns the number of weekdays (Mon–Fri) between two dates.
YEARS_AGO	Calculates the number of years since a given date.

String Operators

Operator	Description
calculated_name	Accesses the calculated name of an instance.
CONCAT	Combines two values into one new value, specifying what should separate the two.
ENDS_WITH	Returns true if a string ends with the given suffix.
format	Takes a string template and replaces named placeholders with provided values.
JOIN	Combines a list of values into one new value by appending them.
LEFT	Returns the first n characters (or elements) from a string or list.
LEN	Returns the length of a string, list, or dictionary. Alias for COUNT.
LEVENSHTEIN	Returns the number of single-character edits needed to transform one string into another.
LOWER	Converts a string to lowercase.
MAKE_FILENAME	Converts a string into a safe filename.
MARKDOWN_TABLE	Renders a list of dictionaries as a Markdown table.
PAD_LEFT	Pads a string on the left to the given width. Default fill is a space.
PAD_RIGHT	Pads a string on the right to the given width. Default fill is a space.
REPLACE	Replaces all occurrences of a value in a string with another value.
REPLACE_CHARS	Replaces characters in a string one-for-one using two equal-length character sequences.
RIGHT	Returns the last n characters (or elements) from a string or list.
SLICE	Returns a portion of a string or list between a start and end index.
SPLIT	Splits a string by a separator into a list. Optional max splits.
STARTS_WITH	Returns true if a string starts with the given prefix.
STRING_TO_JSON	Parses a JSON-encoded string and returns the corresponding dictionary or list.
TRANSLATE_STRING	Returns a translation marker for a custom string key, resolved at render time.
TRIM	Removes whitespace (or specified characters) from the beginning and end of a string.
TRIM_LEFT	Removes whitespace (or specified characters) from the beginning of a string.
UPPER	Converts a string to uppercase.
UUID	Generates a random UUID string.

List Operators

Operator	Description
[]	Creates a new list from single values, allowing other list operators to perform actions on the new list.
[]	Accesses an element of a list by its zero-based index.
ALL	Evaluates if all values in a list are true.
ANY	Evaluates if at least one value in a list is true. Alias for SOME.
APPEND	Returns a new list with a single element appended to the end. Does not mutate the original.
contains	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.
contains all	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.
contains any	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	Returns the length of a list, dictionary, or string. Alias for LEN.
CUSTOM_MAX	Returns the maximum element in a list as ranked by a second ordering list.
FILTER	Removes all occurrences of a specified value from a list.
filter()	Applies a conditional expression to a list, keeping only elements where the condition is true.
FILTER_FALSE	Removes all false elements from the provided arguments.
FILTER_UNKNOWN	Removes all unknown values from a list.
FIRST_ELEMENT	Returns the first element from a list.
FLATTEN	Extracts values from a list of dictionaries by key, or concatenates a list of lists into a single list.
in	Checks if a value is present in a taxonomy.
INDEX_OF	Returns the index of the first occurrence of a value in a list or string. Returns -1 if not found.
INTERSECTION	Returns the elements that appear in both lists.
LAST_ELEMENT	Returns the last element from a list.
MAP	Performs the same action on each individual value in a list.
map()	Performs the same action on each individual value in a list using method syntax.
not in	Evaluates to true if the given value is absent from the specified taxonomy.
REVERSE	Reverses the order of elements in a list.
SET	Removes duplicates from a list.
SET_DIFFERENCE	Returns the elements in the first set that are not in the second set.
SOME	Evaluates if any value in a list is true.
SORT	Sorts a list.
UNION	Combines the elements of two sets into one single set.

Dictionary Operators

Operator	Description
{}	Creates a new dictionary from key-value pairs, allowing other dictionary operators to perform actions on the new dictionary.

Special Operators

Operator	Description
:=	Assignment, which can have any kind of expression on the right side of the operator.
ensure	Makes sure a case contains at least, for example, 1 Person. (replaces create)
get_attr	Gives access to named properties of an instance using expressions.
get_properties	Returns specific information on an instance's properties.
GET_TRANSLATED_ATTR	Like get_attr, but returns the translated display value of the attribute.
has_attr	Returns true if an instance has a given attribute defined.
instances	Returns all instances of the given type(s) living on the platform.
instances_exist	Returns true if the case has at least one instance of the specified type(s).
is	Basic assignment of a variable.
IS_UNIQUE_NAME	Returns true if no active instance of the given type with that name exists.
NAME_AND_LOG	Evaluates an expression, logs its result under a name for debugging, and returns the result unchanged.
ontology	Sets a condition based on the type of ontology.
PICK_OR_DEFAULT	Returns a value from an allowed list if it matches the input, otherwise returns a default.
PRETTY_PRINT	Formats a dictionary or list as an indented, human-readable JSON string.
roles	Sets a condition based on role(s).
self	Refers to the current instance where you use it.
Translate (.$)	Accesses a taxonomy attribute in a way that its value is translated into the requested language at render time.

Unknown Operators (Three-Valued Logic)

Operator	Description
AVG_OF_ANY	Calculates the average of available values.
CONCAT_OF_ANY	Like CONCAT, but only combines the values that are available (not unknown).
JOIN_OF_ANY	Like JOIN, but only joins the values that are available (not unknown).
known	Sets a condition for when a property is not unknown.
LIST_OF_ANY	Builds a list of only the values that are available out of all the values it is given.
MAX_OF_ANY	Returns the highest out of available values.
MIN_OF_ANY	Returns the lowest out of available values.
SNEAKY	Wrapping an expression with SNEAKY has the system ignore the expression, if the information used in it is not available.
SUM_OF_ANY	Adds available numbers.
UNION_OF_ANY	Creates a combined list of the available values and lists out of all values and lists you provide.
unknown	Sets a condition for when a property is unknown.