The document summarizes the key changes in the DMN 1.4 specification. It introduces three new boxed expression types - conditional, iterator, and filter. It also describes new features like collection markers on decisions, current date/context FEEL functions, and improved rounding/text FEEL functions. DMN 1.4 was approved in December 2021 and will be published officially in early 2022, with the next version 1.5 planned for March 2023.

1. What is new in DMN 1.4?
Simon Ringuette – R&D Lead at Trisotech

2. Motivations behind DMN 1.4
• Addressing gray area of interpretation in previous version of the
documentation.
• Addressing shortcomings based on user feedback and vendor
experiences with the specification.

3. History of DMN
2
0
1
5
Original release of the DMN
Specification
DMN 1.0
2
0
1
6
Addressing major issues with the DMN
XML interchange
DMN 1.1
2
0
1
9 - DMN Diagram Interchange
- Decision Service as Invokable
- Ellipsis Marker
- Decision Table annotations
DMN 1.2
2
0
2
1
- Group annotations
- Temporal functions
- Context FEEL functions
- Improvements to the typing
DMN 1.3
2
0
2
2
- Three new type of boxed expression
- Collection marker on decisions
- New FEEL functions
DMN 1.4

4. Three New Boxed Expression
Conditional
Graphical structure representing a conditional execution based on a boolean
criteria.
Iterator
Graphical structure representing the evaluation of a boxed expression for each
element of a collection.
Filter
Graphical structure representing filtering in a collection based on a criteria that
can be expressed using another boxed expression.

5. Conditional
• Modeled after the if/then/else FEEL statements.
• Contains 3 blocks: if, then, else. Each of them able to contain
various boxed expression types.

6. Conditional - Example
A literal expression that applies a different expression
depending on the current date to calculate a rate based on a
Number of Months can be transformed in a conditional
boxed expression that leverages decision tables.

7. Iterator
• Modeled after the for/every/some FEEL statements.
• Contains 3 blocks: for, in, return OR every/some, in, satisfies.
Each of them able to contain various boxed expression types.

8. Iterator - Example
A literal expression that iterate over different Loans to
calculate a rate on each one of them can be
transformed into an iterator boxed expression that
leverages an invocation boxed expression.

9. Filter
• Modeled after the bracket operator of FEEL.
• Contains two blocks: a collection and a filter. Each of them able
to contain various boxed expression types.

10. Filter - Example
A literal expression that filters Loans to keep only the
ones matching an Amount and Period criteria can be
transformed into a filter boxed expression that
leverages a context boxed expression.

11. Benefits of the new
boxed expression
• Allows to stay at the boxed expressions level of abstraction for
more use cases.
• Allows to reuse business-friendly constructs such as decision
tables in conditional, iteration and filters which was nearly
impossible to do using literal expressions.

12. Example
Annotation
Iterator
Conditional

13. Collection Marker on Decisions
• A collection marker was added to decisions to depict that the
output of that decision is a collection.
• Like the input data collection marker but at the top of the shape
given that it is the output that is a collection.

14. New FEEL Functions – Current Date
Function Name Description
now Returns the current date and time
today Returns the current date
These two functions were widely integrated as vendor extensions by most DMN engines already.
Models using these two functions are not guaranteed to always produce the same result given the same
inputs. It is often a good practice to provide the “current” date as an input.

15. New FEEL Functions – Context
Function Name Description
context Creates a new context based on a list of key and values
context put Creates a new context that includes the new entry, or overriding the existing value
context merge Creates a new context that includes all entries from given contexts
key 1: 1
key 2: 2
key 1: 1
key 2: 2
key 3: 3
key 1: 1
key 2: 2
key 3: 3
key 4: 4

16. New FEEL Functions – Rounding
• Introduction of a second optional parameter called scale for the
existing floor and ceiling methods:
floor(n, scale), ceiling(n, scale)
Example: floor(1.56) = 1 but floor(1.56, 1) = 1.5
• Introduction of additional rounding methods: round up, round
down, round half up, round half down.

17. New FEEL Functions – Rounding
Function Name Description
Ceiling Next integer moving toward positive infinity
Round up Next integer moving away from zero
Round half up Next integer moving away from zero if at least halfway or previous integer otherwise
Floor Next integer moving toward negative infinity
Round down Next integer moving toward zero
Round half down Next integer moving toward zero if at least halfway or previous integer otherwise
ceiling(22.3) = round up(22.3) = 23 but round half up(22.3) = 22
floor(-5.2) = -6 but round down(-5.2) = round half down(-5.2) = -5

18. New FEEL Functions – Text
• A new string join function was added.
• Uses two parameters:
• Collection of strings to join
• Optional delimiter character(s)
string join([“a”,”b”,”c”], “/”) = “a/b/c”

19. DMN 1.4
• Approved by the OMG’s Architecture Board in December 2021.
• Should be published as an official specification in Q1 2022.
• DMN 1.5 currently has a target date of March 2023.