DMN: B-FEEL implementation

[gitgabrio]

Verify/implement the new B-FEEL version inside DMN.
B-FEEL should be optionally enabled (i.e., disabled by default) setting expression language to

“https://www.omg.org/spec/DMN/20240513/B-FEEL/”

Verify the specs

B-FEEL - Proposal.docx

Requires

• Two different implementations of FEEL execution #73
• DMN: Split EvalHelper to better focused classes #1187
• DMN - Remove code path duplication for code gen execution #1206
• DMN - review extended functions and profile #1344

to be fixed, before

@baldimir @yesamer

[jomarko]

@gitgabrio hi, I tried to check what change, if any, is needed on the Editor side and this question came to my mind. Is it valid, that more implementations can be specified in the model?

In the root of the model, Editor has this:

However, we have also this on the expression cell level:

Is a valid scenario, lets say model root set expression as FEEL and some expression cell set it as B-FEEL or vice versa?

Also, I wonder what is your opinion about Expression langugage to be plain text input versus maybe dropdown of values?

[gitgabrio]

@jomarko
thanks for spotting that!
So, first of all expressionLanguage can be overridden

From spec:

An instance of Definitions may specify an expressionLanguage, which is a URI that identifies the
default expression language used in elements within the scope of this Definitions. This value may be
overridden on each individual LiteralExpression.

About "plain text input versus maybe dropdown of values", specs (IINW) does not provide a defined list of allowed ones, just mention that expressionLanguage maybe anything in URI format (there is also a mention to XPATH 2, e.g.

An instance of LiteralExpression may include importedValues, which is an instance of a subclass
Import that identifies where the text of the LiteralExpression is located. importedValues is an
expression that selects text from an imported document. An instance of LiteralExpression SHALL NOT
have both a text and importedValues. The importType of the importedValues identifies the type of
document containing the imported text and SHALL be consistent with the expressionLanguage of the
LiteralExpression element. The expressionLanguage of the importedValues element identifies
how the imported text is selected from the imported document. For example, if the importType indicates an
XML document, the expressionLanguage of importedValues could be XPATH 2.0.

To sum-up, we'll need to discuss and review the implementation with @baldimir and @yesamer, to double-check the current implementation about this detail.

Thanks again!!!