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.

Operator | Category | Description |

| â€‹Booleanâ€‹ | Compares. Evaluates to either true or false, delivering different outcomes. |

| â€‹Booleanâ€‹ | Compares, true for 'is not equal to'. |

| â€‹Booleanâ€‹ | Compares, true for 'greater than'. |

| â€‹Booleanâ€‹ | Compares, true for 'equal to or greater than'. |

| â€‹Booleanâ€‹ | Compares, true for 'less than'. |

| â€‹Booleanâ€‹ | Compares, true for 'equal to or less than'. |

| â€‹Specialâ€‹ | Assignment, which can have any kind of expression on the right side of the operator. |

â€‹Mathematicalâ€‹ | Perform basic mathematical calculations. | |

| â€‹Listâ€‹ | Creates a new list from single values, allowing other list operators to perform actions on the new list. |

| â€‹Dateâ€‹ | Takes a date and adds a specified number of years to it. |

| â€‹Dateâ€‹ | Takes two dates, and checks if the first one comes after the second one. |

| â€‹Dateâ€‹ | Takes two dates, and checks if the first one comes after, or is the same as, the second one. |

| â€‹Listâ€‹ | Evaluates if all values in a list are true. |

| â€‹Booleanâ€‹ | Sets as condition that both expressions have to be true to have the entire expression evaluate to 'true'. |

| â€‹Booleanâ€‹ | Similar as above, but when using 'and then', the second question is only asked when the first evaluates to 'true'. |

| â€‹Mathematicalâ€‹ | Calculates the average value. |

| â€‹Knownâ€‹ | Calculates the average of available values. |

| â€‹Dateâ€‹ | Takes two dates, and checks if the first one comes before the second one. |

| â€‹Dateâ€‹ | Takes two dates, and checks if the first one comes before, or is the same as, the second one. |

| â€‹Stringâ€‹ | Accesses the calculated name of an instance. |

| â€‹Mathematicalâ€‹ | Returns the value of the given parameter, rounded up to a whole number. |

| â€‹Stringâ€‹ | Combines two values into one new value, specifying what should separate the two. |

| â€‹Listâ€‹ | 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. |

| â€‹Listâ€‹ | 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. |

| â€‹Listâ€‹ | 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. |

| â€‹Listâ€‹ | Returns the number of occurrences of the given parameter. |

| â€‹Specialâ€‹ | Makes sure a case contains at least, for example, 1 Person. (replaces |

| â€‹Listâ€‹ | Returns the first element from a list. |

| â€‹Mathematicalâ€‹ | Returns the value of the given parameter, rounded down to a whole number. |

| â€‹Specialâ€‹ | Gives access to named properties of an instance using expressions. |

| â€‹Specialâ€‹ | Returns specific information on an instance's properties. |

| â€‹Listâ€‹ | Checks if a value is present in a taxonomy. |

| â€‹Specialâ€‹ | Returns all instances of the given type(s) living on the platform. |

| â€‹Specialâ€‹ | Basic assignment of a variable. |

| â€‹Stringâ€‹ | Combines a list of values into one new value by appending them. |

| â€‹Knownâ€‹ | Sets a condition for when a property is not unknown. |

| â€‹Knownâ€‹ | Builds a list of only the values that are available out of all the values it is given. |

| â€‹Listâ€‹ | Performs the same action on each individual value in a list. |

| â€‹Mathematicalâ€‹ | Returns the highest value. |

â€‹ | â€‹Knownâ€‹ | Returns the highest out of available values. |

| â€‹Mathematicalâ€‹ | Returns the lowest value. |

| â€‹Knownâ€‹ | Returns the lowest out of available values. |

| â€‹Booleanâ€‹ | A negation. |

| â€‹Listâ€‹ | Evaluates to true if the given value is absent from the specified taxonomy. |

| â€‹Dateâ€‹ | Current date and time. |

| â€‹Specialâ€‹ | Sets a condition based on the type of ontology. |

| â€‹Specialâ€‹ | The rule can accept, but will not require, for example, a third person. |

| â€‹Booleanâ€‹ | When just one of the two given expressions is true, the entire expression evaluates to 'true'. |

| â€‹Booleanâ€‹ | Similar to above, but the second question is only asked if the first has been answered. |

| â€‹Specialâ€‹ | Sets a condition based on role(s). |

| â€‹Mathematicalâ€‹ | Returns the value of the given parameter, rounded to a whole number. |

| â€‹Specialâ€‹ | Refers to the current instance where you use it. |

| â€‹Knownâ€‹ | Wrapping an expression with |

| â€‹Listâ€‹ | Evaluates if any value in a list is true. |

| â€‹Dateâ€‹ | Takes a date and subtracts a specified number of years to it. |

| â€‹Mathematicalâ€‹ | Adds up numbers. |

| â€‹Knownâ€‹ | Adds available numbers. |

| â€‹Mathematicalâ€‹ | Multiplies values in one list with values on the same index in another list. Returns the sum of the multiplications. |

| â€‹Listâ€‹ | Combines the elements of two sets into one single set. |

| â€‹Knownâ€‹ | Creates a combined list of the available values and lists out of all values and lists you provide. |

| â€‹Knownâ€‹ | Sets a condition for when a property is unknown. |

| â€‹Dateâ€‹ | Calculates the number of years since a given date. |