Using Advanced Literal Expressions (Functions in DMN Decision Elements)

If you have modeled Decision Model and Notation (DMN) diagrams, you are likely familiar with DMN expressions for decision logic, as explained in Model a decision.

In addition, you can use SAP Signavio's advanced literal expressions based on friendly enough expression language (FEEL) as part of the DMN standard.

For more information, see Chapter 9 in the OMG PDF document: Decision Model and Notation Information published on non-SAP site .

Example

A simple example is determining a discount based on the total value of a list of purchased objects. Single commands can be combined in a literal expression.

Product((1 - DiscountRate) * Sum(ListOfItemPrices)).

This calculates the total purchase sum of a list of items, considering a discount. The variables used here correspond to the data types defined in input data element's attributes and can be set when simulating the DMN diagram.

You can also use standard operators ( +, -, *, /, and, or) within a literal expression.

(1 - DiscountRate) * Sum(ListOfItemPrices).

For more information, see section Documentation of all literal expressions.

Using Literal Expressions in Decision Tables

Here are the steps to create decision logic for determining a discount based on the total sum of purchased items.

Create the Purchased items data input element.

The input should be a list of numbers (type currency).
Create a decision element and label it Determine discount.
Connect the decision element to the data input element.
Choose the table icon (Decision) in the upper left corner of the decision element to open the Decision Table Editor.
Select the header and delete the input reference in the table to be able to insert a literal expression.
Type in =.

The system displays available variables and functions.
Type in Sum and select the Sum function.
Insert the variable PurchasedItems as a parameter of Sum.
Insert the literal expression Sum(PurchasedItems).

As a result, the decision logic's input data is the sum of all purchased items. You can further define the decision logic.

Using Literal Expressions Instead of Decision Tables

You can also use literal expressions instead of decision tables. Split a decision into two connected elements: one with a decision table and one with literal expression logic.

Here, Calculate total sum and Determine discount are two separate decision elements.

The first element calculates the total sum of purchased items.
The second element determines the discount based on the total sum.

Here are the steps to model the first decision without using a decision table.

Open the decision table editor and switch to the Literal expressions tab.
There, insert the literal expression to calculate the sum of items.

As a result, the decision element returns the sum of items as a data output and can be referenced by the following decision element.

In a complex literal expression, you can define variables, known as boxed contexts, and reference them in our decision function to improve the readability of a literal expression.

Documentation of all Literal Expressions

This section lists all available literal expressions, grouped by operation type.

Arithmetic Operations

Name	Literal Expression	Description	Example
Abs	Abs(number):NUMERIC	Returns the absolute value of a number.	Abs(-5) returns 5.
Ceiling	Ceiling(number):NUMERIC	Returns a number rounded up to the next integer.	Ceiling(1.3) returns 2.
Count	Count([num1 ,num2, num3]):NUMERIC	Returns the number of elements of the given list.	daysCount(["item1", "item2", "item3"]) returns 3.
Floor	Floor(number):NUMERIC	Returns a number rounded down to the next integer.	Floor(1.6) returns 1.
Integer	Integer(number): NUMERIC	Returns the integer part of a number.	Integer(1.34) returns 1.
Modulo	Modulo(divident, divisor):NUMERIC	Returns the remainder of the divident divided by the divisor.	Modulo(4, 3) returns 1.
Percent	Percent(number):NUMERIC	Returns the number divided by 100.	Percent(10) returns 0.1.
Power	Power(base, exponent):NUMERIC	Returns the base raised to the power of the exponent.	Power(2, 3) returns 8.
Product	Product([factor1, factor2, factor3]):NUMERIC	Returns the product of a list of factors.	Product([2, 3, 4]) returns 24.
Round	Round(number,digits):NUMERIC	Returns a number rounded to the corresponding number of digits.	Round(3.44,1) returns 3.4.
RoundDown	RoundDown(number, digits):NUMERIC	Returns a number rounded down to the corresponding number of digits.	RoundDown(1.3674, 2) returns 1.36.
RoundUp	RoundUp(number, digits):NUMERIC	Returns a number rounded up to the corresponding number of digits.	Abs(1.344, 2) returns 1.35.
Sum	Sum([number1, number2, number3]):NUMERIC	Returns the sum of a list of values.	Sum([1, 2, 3, 4, 5]) returns 15.

Date and Time Operations

Name	Literal Expression	Description	Example
Date	Date(year, month, day):DATE	Returns a date using the standard parameters of a date: year, month, day	Date(2015, 12, 25) returns 2015-12-25.
DateTime	DateTime(day, month, year, hour, minute, second, hourOffsett):DATE	Returns the dateTime using the standard parameters of a data time. The last parameter 'hourOffset' is optional.	DateTime(25, 12, 2015, 12, 15, 0, 1) returns 2015-12-24T12:15:00.000+01:00.
Day	Day(datetime):NUMERIC	Returns the day part of a datetime.	Day(2015-12-24T12:15:00.000+01:00) returns 24.
DayAdd	DayAdd(datetime, days to add):DATE	Returns the date plus the provided number of days.	DayAdd(2015-12-24T12:15:00.000+01:00, 1) returns 2015-12-25T12:15:00.000+01:00.
DayDiff	DayDiff(datetime1, datetime2):NUMERIC	Returns the amount of full	DayDiff(2015-12-24T12:15:00.000+01:00, 2015-12-25T12:15:00.000+01:00) returns 1.
Hour	Hour(datetime):NUMERIC	Returns the hour part of a datetime.	Hour(2015-12-24T12:15:00.000+01:00) returns 12.
HourDiff	Hour(time):NUMERIC	Returns the amount of full hours between two dates.	HourDiff(2015-12-24T12:15:00.000+01:00, 2015-12-24T14:15:00.000+01:00) returns 2.
Minute	Minute(time):NUMERIC	Returns the minute part of a datetime.	Minute(2015-12-24T12:15:00.000+01:00) returns 15.
MinutesDiff	MinutesDiff(datetimes1, date2times):NUMERIC	Returns the amount of full minutes between two dates.	MinutesDiff(2015-12-24T12:15:00.000+01:00, 2015-12-24T13:15:00.000+01:00) returns 60.
Month	Month(datetime):NUMERIC	Returns the month part of a datetime.	Month(2015-12-24T12:15:00.000+01:00) returns 12.
MonthAdd	MonthAdd(datetime, months_to_add):DATE	Returns the datetime plus the number of months.	MonthAdd(2015-10-10T12:15:00.000+01:00, 1) returns 2015-11-10T12:15:00.000+01:00.
MonthDiff	MonthDiff(datetime1, datetime2):NUMERIC	Returns the amount of full months between two dates.	MonthDiff(2015-10-10T12:15:00.000+01:00, 2015-11-10T12:15:00.000+01:00) returns 1.
Now	Now():DATE	Returns current datetime.	Now() could have returned 2015-11-10T12:15:00.000+01:00.
Today	Today():DATE	Returns the current date.	Today() could have returned 2015-11-10.
Weekday	Weekday(datetime):NUMERIC	Returns a number (1 to 7) representing the day of the week.	weekday(2016-02-09T12:15:00.000+01:00) returns 3.
Year	Year(datetime):NUMERIC	Returns the year part of a datetime.	Year(2016-02-09T12:15:00.000+01:00) returns 2016.
YearAdd	YearAdd(datetime, years_to_add):DATE	Returns the datetime plus the number of years.	YearAdd(2016-02-09T12:15:00.000+01:00, 1) returns 2017-02-09T12:15:00.000+01:00.
YearDiff	YearDiff(datetime1, datetime2):NUMERIC	Returns the amount of full years between two dates.	YearDiff(2016-02-09T12:15:00.000+01:00, 2017-02-09T12:15:00.000+01:00) returns 1.

List Operations

Name	Literal Expression	Description	Example
Append	Append(list, element): LIST	Adds the element to a copy of the provided list. Returns the manipulated copy.	Append([2.5, 5.8, 4.3], 6.7) returns [2.5, 5.8, 4.3, 6.7].
AppendAll	AppendAll(list1, list2): LIST	Adds all elements from the second provided list to a copy of the first one. Returns the manipulated copy.	AppendAll([2.5, 5.8, 4.3], [2.1, 3.5, 7.4]) returns [2.5, 5.8, 4.3, 2.1, 3.5, 7.4].
AreElementsOf	AreElementsOf(list1, list2): BOOLEAN	Determines whether list2 contains all elements of list1.	AreElementsOf(["item2, item3"], ["item1", "item2", "item3"]) returns true.
ContainsOnly	ContainsOnly(list1, list2): BOOLEAN	Determines whether list1 contains only elements of list2.	ContainsOnly(["item1", "item2"], ["item2", "item3"]) returns false.
Flatten	Flatten(list): list	Returns a flattened list. Will flatten all nested lists to a single list.	Flatten([[1, 2], [3, 4], [5, 6]]) returns [1, 2, 3, 4, 5, 6].
NotContainsAny	NotContainsAny(list1, list2): BOOLEAN	Determines whether list1 contains any element of list2.	NotContainsAny(["item1", "item2"], ["item2", "item3"]) returns false.
Remove	Remove(list, element): LIST	Removes the specified element from the specified list. This expression is available only in the Literal Expressions Editor (not in the Decision Table Editor).	Remove(["item1", "item2"], "item1") returns ["item2"].
RemoveAll	RemoveAll(list1, list2): LIST	Removes all elements of list2 from list1. This expression is available only in the Literal Expressions Editor (not in the Decision Table Editor).	Remove(["item1", "item2", "item3"], ["item1", "item2"]) returns ["item3"].
SortAsc	SortAsc(list): list	Returns the list sorted in ascending order.	SortAsc([3, 1, 2]) returns [1, 2, 3]; SortAsc(["c", "a", "b"]) returns ["a", "b", "c"].
SortDesc	SortDesc(list): list	Returns the list sorted in descending order.	SortDesc([3, 1, 2]) returns [3, 2, 1]; SortDesc(["c", "a", "b"]) returns ["c", "b", "a"].
Union	Union(list1, list2,...): list	Merges two or more lists into a single list and removes all duplicate values.	Union([1,2,3,4], [4,5,6]) = [1,2,3,4,5,6].
Zip	Zip(attributes, values1, ..., valuesN): LIST	Assembles a list of objects out of a list of attributes and multiple lists of values. Caution Before version 10.11.0 of the Decision Manager, the values were passed to the function as a list of lists, for example: Zip(["id", "value"], [[23a3e98, c45da1b], [40, 120]]) Literal expressions that used the old Zip function have been automatically transformed to the new syntax.	Zip(["id", "value"], [23a3e98, c45da1b], [40, 120]) returns [{id: 23a3e98, value: 40},{ id: c45da1b, value: 120}].

Statistical Operations

Name	Literal Expression	Description	Example
Avg	Avg([number1, number2, number3]):NUMERIC	Returns the average of the values of the given list.	Avg([3,5]) returns 4.
Max	Max([number1, number2, number3]):NUMERIC	Returns the maximum value of the given list.	Max([5, 4, 10]) returns 10.
Median	Median([number1, number2, number3]):NUMERIC	Returns the median value of the given list.	Median([2, 5, 10, 12, 34, 35]) returns 11.
Min	Min([number1, number2, number3]):NUMERIC	Returns the minimum value of the given list.	Min([5, 4, 10]) returns 4.
Mode	Mode([number1, number2, number3]):NUMERIC	Returns the most frequently occurring value of the given list. Returns the first (most left) most frequent value, if several values occur most frequently (e.g. two values appear each two times).	Mode([1, 2, 4, 4, 5, 6]) returns 4.

Text Handling

Name	Literal Expression	Description	Example
Concat	Concat([text1, text2, text3]):TEXT	Returns the concatenation of the given list of text values.	Concat(["Hello ", "World", "!"]) returns "Hello World!".
Contains	Contains(text, substring): BOOLEAN	Determines whether text contains the substring.	Contains("Hello World!", "o World") returns true.
EndsWith	EndsWith(text, suffix): BOOLEAN	Determines whether text ends with the suffix.	endsWith("Hello World!", "!") returns true.
IsAlpha	IsAlpha(text):BOOLEAN	Determines whether the text contains only alphabetic characters (A-Z, a-z). Umlauts and similar characters (e.g.Ä, Å ß) must not be included.	IsAlpha("abcdefg5") returns false.
IsAlphanumeric	IsAlphanumeric(text):BOOLEAN	Determines whether the text contains only alphanumeric characters (A-Z, a-z, 0-9). Umlauts and similar characters (e.g. Ä, Å ß) must not be included.	isAlphanumeric("abcdefg5") returns true.
IsNumeric	IsNumeric(text):BOOLEAN	Determines whether the text is a valid number containing only plus or minus sign, digits, commas, and decimal points.	IsNumeric("2.3.5") returns false
IsSpaces	IsSpaces(text):BOOLEAN	Determines whether the text contains only spaces.	IsSpaces(" ") returns true.
Left	Left(text, num_chars):TEXT	Returns the character sequence of the length num_chars from the start of a text string.	Left("Hello World!", 5) returns "Hello".
Len	Len(text):NUMERIC	Returns the number of characters in a text string.	Len("five") returns 4.
Lower	Lower(text):TEXT	Returns the text string with all letters converted to lowercase.	Lower("UPPER") returns upper.
Mid	Mid(text, start, num_chars):TEXT	Returns the character sequence of the length num_chars from the corresponding starting position of a text string.	Mid("Hello World!", 6, 5) returns "World".
Number	Number(text):NUMERIC	Returns the numerical value represented in the text string. Only a period (.) is allowed as a separator.	Number("5") returns 5.
Number (Default Value)	Number(text, default_value):NUMERIC	Returns the numerical value represented in the text string. Only a period (.) is allowed as a separator. Returns default_value if unable to convert text into number.	Number("5,5", 10) returns 10 (Number("5.5", 10) returns 5.5).
Right	Right(text, num_chars):TEXT	Returns the character sequence of the length num_chars from the end of a text string.	Right("Hello World!", 7) returns "World!".
StartsWith	StartsWith(text, prefix): BOOLEAN	Determines whether text starts with the prefix.	StartsWith("Hello World!", "Hello") returns true.
SubstringAfter	SubstringAfter(string, string): string	Returns the part of the first given string that is located after the given second string.	SubstringAfter("Hello World","Hello ") returns "World".
SubstringBefore	SubstringBefore(string, string): string	Returns the part of the first given string that is located before the given second string.	SubstringBefore("Hello World"," World") = "Hello".
Text	Text(num, format_text):TEXT	Returns a numeric value as a text string in a specific format. The format is specified by the placeholders # and 0 and a decimal point..	Text(1, "#.000") returns "1.000".
TextOccurrences	TextOccurrences(find_text, within_text):NUMERIC	Returns the number of occurrences of find_text within within_text.	TextOccurrences("can", "Can you can a can as a canner can can a can?") returns 6.
Trim	Trim(text):TEXT	Returns the text string with all spaces removed except single spaces between words.	Trim("Hello World! ") returns "Hello World!".
Upper	Upper(text):TEXT	Returns the text string with all letters converted to uppercase.	Upper("lower") returns "LOWER".

Logical Operators

Name	Literal Expression	Description	Example
Not	Not(boolean): BOOLEAN	Negates the input boolean.	Example: Not(true) returns false.