Decision Model and Notation Avatar
  1. OMG Specification

Decision Model and Notation — Open Issues

  • Acronym: DMN
  • Issues Count: 29
  • Description: Issues not resolved
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Issues not resolved

Issues Summary

Key Issue Reported Fixed Disposition Status
DMN13-150 Support for recursive calls by Business Knowledge Models DMN 1.2 open
DMN13-127 Incorrect claim about the Unicode character range and EBNF character expressions DMN 1.2b1 open
DMN13-144 instance of clarification DMN 1.2 open
DMN13-132 type conversions are too spread out in Ch 10 DMN 1.2b1 open
DMN13-126 Built-in functions only described in chapter "10.3.2.6 Context", and not described in the "10.3.4 Built-in functions" DMN 1.2b1 open
DMN13-125 Disambiguation for Modulo / Remainder function DMN 1.2b1 open
DMN13-98 Example: Applicant Data.Monthly.Income and Applicant Data.Monthly.Expenses values inverted DMN 1.2b1 open
DMN13-122 "get value" and "get entries" function not in built-in functions list DMN 1.2b1 open
DMN13-108 Lack of visual notation for processing of / iteration over lists in FEEL DMN 1.2 open
DMN13-139 Add built-in functions to support Allen's interval algebra DMN 1.2b1 open
DMN13-140 Fix grammar rule references in FEEL grammar DMN 1.2b1 open
DMN13-141 Allegedly bug in Table Table 40 Examples of equivalence and conformance relations DMN 1.2b1 open
DMN13-142 Spec does not clarify meaning of hex value DMN 1.2b1 open
DMN13-143 Should add a new unicode escape syntax DMN 1.2b1 open
DMN13-145 Support for function types in metamodel and XSD DMN 1.2b1 open
DMN13-149 Clarification on DMN case sensitivity of timezones DMN 1.2 open
DMN13-114 properly define type(e) DMN 1.2 open
DMN13-133 Wrong example in chapter "10.3.1.5" DMN 1.2b1 open
DMN13-131 Make explicit reference to sample standard deviation DMN 1.2b1 open
DMN13-124 Disambiguation for Modulo / Remainder function DMN 1.2b1 open
DMN13-120 Minor typos in the FEEL grammar DMN 1.2b1 open
DMN13-109 Ambiguty for the source/target of DMNEdge when there is multiple depictions of its source and target DMN 1.2 open
DMN13-121 example shows literal inline function definition whereas grammar says function definitions only in boxed expressions. DMN 1.2b1 open
DMN13-134 Inconsistency DMNv1.2 dropping [a]=a and get entries example DMN 1.2b1 open
DMN13-123 "instance of" not possible with some built-in functions DMN 1.2b1 open
DMN13-111 Remove the limitation that the second operand of exponentiation be an integer DMN 1.2b1 open
DMN13-106 Remove reference to SQL and PMML three value logic to eliminate misinterpretation DMN 1.2b1 open
DMN13-90 Allow representation of black-box Decision Service DMN 1.2 open
DMN13-91 Fix interchange of links to objects in BPMN/BMM DMN 1.2 open

Issues Descriptions

Support for recursive calls by Business Knowledge Models

  • Key: DMN13-150
  • Status: open  
  • Source: Montera Pty Ltd ( Greg McCreath)
  • Summary:

    The definition of "well formed" for a BusinessKnowledgeModel excludes the notion of the encapulatedLogic of a BusinessKnowledgeModel being able to invoke itself to permit recursion. There is no means to define a 'self' relationship via knowledgeRequirements - the spec forbids it.

    However, vendors are currently supporting BusinessKnowledgeModel recursion simply by permitting a BusinessKnowledgeModel's encapulatedLogic to invoke the contained BusinessKnowledgeModel as a function using the contained BusinessKnowledgeModel's name. I propose we formalise this in the spec.

    I propose that after the definition of well-formed on page 56/57 (repeated below):

    "An instance of BusinessKnowledgeModel is said to be well-formed if and only if, either it does not have any knowledgeRequirement, or all of its knowledgeRequirement elements are well-formed. That condition
    entails, in particular, that the requirement subgraph of a BusinessKnowledgeModel element SHALL be acyclic, that is, that a BusinessKnowledgeModel element SHALL not require itself, directly or indirectly. "

    The following paragraph is added:

    "However, the encapsulatedLogic within a BusinessKnowledgeModel may invoke itself in a recursive manner by using the name of the containing BusinessKnowledgeModel as an invokable name."

  • Reported: DMN 1.2 — Sat, 6 Apr 2019 02:38 GMT
  • Updated: Tue, 23 Apr 2019 16:35 GMT

Incorrect claim about the Unicode character range and EBNF character expressions

  • Key: DMN13-127
  • Status: open  
  • Source: Fujitsu ( Keith Swenson)
  • Summary:

    This is a trivial typo, and the fix is easy.

    Lower on page 108 it says: "the character range that includes all Unicode characters is [\u0-\u10FFF]." This range specified has less than 70,000 characters.

    I don't think your intent is to limit implementations to 70K characters and in fact in places (e.g. grammar rule #30) character values larger than this are mentioned.

    "all Unicode characters" is actually the entire range of 32-bit values (minus some control codes: hundreds of millions of characters, most of which are undefined). Instead you are defining a SUBSET of this that will be allowed.

    Second, the most common implementation of Unicode uses UTF-16, and as a consequences OF THIS ENCODING, the range of representable characters is 0 through 10FFFF. Note that is six hex digits, there are four F digits. There are over a million characters in this range.

    (1) Nowhere in the spec does is say you are limiting characters to the UTF-16 range. This should be explicitly stated if that is your intent.

    (2) The phrase on page 108 should be changed to; "DMN allows the use of unicode characters in the range of [\u0-\u10FFFF]."

    (3) The specification of EBNF character expression should be changed to allow 6 hex digits, currently it says you can only use five digits max.

  • Reported: DMN 1.2b1 — Mon, 31 Dec 2018 17:00 GMT
  • Updated: Tue, 23 Apr 2019 16:34 GMT
  • Attachments:

instance of clarification


type conversions are too spread out in Ch 10

  • Key: DMN13-132
  • Status: open  
  • Source: Goldman Sachs ( Octavian Patrascoiu)
  • Summary:

    The spec does not contain a section where the type conversions are described, hence they end-up spread across the spec. For example, a particular case of invocation conversion is described in 10.3.2.5:

    Similarly, on a function f( p ) where the domain of the formal parameter p does not include lists, but on an invocation f( pa ) the
    actual parameter pa is a singleton list where the type of pa[1] belongs to the domain of p, then pa[1] should be used instead.

    Consolidating all of them in one paragraph will make the spec more readable and easier to change in the future (e.g. we want to apply conversions in other context). It will also help us to identify gaps in the spec.

    It's a natural step after adding the type relationships in DMN 1.2.

  • Reported: DMN 1.2b1 — Wed, 30 Jan 2019 16:34 GMT
  • Updated: Tue, 23 Apr 2019 16:15 GMT

Built-in functions only described in chapter "10.3.2.6 Context", and not described in the "10.3.4 Built-in functions"

  • Key: DMN13-126
  • Status: open  
  • Source: Red Hat ( Matteo Mortari)
  • Summary:

    In section "10.3.2.6 Context" two built-in functions are described: get value(), get entries().
    However these functions are not summarized later in section "10.3.4 Built-in functions"

    Describing all built-in functions in latter section "10.3.4 Built-in functions" is important to agree on the function parameters name.

    Agree on the function parameters name is important for invoking function and binding parameters by name, rather than positional.

    I propose to add a new section inside "10.3.4 Built-in functions", with the following:

    10.3.4.x Context function

    Table xx defines Context functions.

    Table xx: Semantics of Context functions

    Name(parameters) Parameter Domain Description Example
    get value(m, key) context, string select the value of the entry named key from context m
    get value({key1 : "value1"}, "key1") = "value1"
    get value({key1 : "value1"}, "unexistent-key") = null
    
    get entries(m) context produces a list of key,value pairs from a context m
    get entries({key1 : "value1"}) = [ { key : "key1", value : "value1" } ]
    get entries({key1 : "value1"})[key="key1"].value = "value1"
    
  • Reported: DMN 1.2b1 — Thu, 15 Nov 2018 15:42 GMT
  • Updated: Thu, 11 Apr 2019 00:46 GMT

Disambiguation for Modulo / Remainder function

  • Key: DMN13-125
  • Status: open  
  • Source: Red Hat ( Matteo Mortari)
  • Summary:

    (please discard the previous JIRA on subject made by me, THIS is the correct one)

    The spec defines "modulo" FEEL built-in function as: "the remainder of the division of dividend by divisor"
    However, this might be subject to ambiguity in the case the Divisor or Dividend are negative, as also mentioned by Wikipedia page which list examples out of several programming languages and systems: https://en.wikipedia.org/wiki/Modulo_operation by saying that "When either a or n is negative, the naive definition breaks down and programming languages differ in how these values are defined".

    FEEL aims to be a Friendly Enough expression language, and especially thinking about DMN practitioners who might be used to Spreadsheet based systems might find misleading if the definition of the FEEL "modulo" gets bind to the Java (default) definition, the following table illustrate the difference:

    Dividend Divisor MOD() from Microsoft Excel, Google Sheets, LibreOffice Calc, Wolfram Alpha, etc. Java % or BigDecimal#remainder or other languages default
    10 4 2 2
    10 -4 -2 2
    -10 4 2 -2
    -10 -4 -2 -2

    or to other implementation languages where the definition of Modulo/Remainder is not explicit, or the default one is not consistent with Spreadsheet default one.

    It is proposed therefore to change the specification in 10.3.4.5 Numeric functions Table 70 for the FEEL "modulo" built-in function
    FROM: "Returns the remainder of the division of dividend by divisor."
    TO: "Returns the remainder of the division of dividend by divisor. In case either dividend or divisor is negative, the result has the same sign of the DIVISOR."

    This would avoid ambiguity by making a clear definition of what should be the sign in case either of the operands are negative.
    This should make this consistent with Spreadsheet based system result of "MOD()" expression, which should address being Friendly Enough for DMN practitioners and DM analyst.
    This would not make the result the same as the default of Java % operator or BigDecimal#remainder, but Java based implementation/Vendor can trivially address the result to be compliant with the spec.

  • Reported: DMN 1.2b1 — Fri, 4 Jan 2019 18:38 GMT
  • Updated: Thu, 11 Apr 2019 00:46 GMT
  • Attachments:

Example: Applicant Data.Monthly.Income and Applicant Data.Monthly.Expenses values inverted

  • Key: DMN13-98
  • Status: open  
  • Source: Red Hat ( Matteo Mortari)
  • Summary:

    Fig 11.28 on page 179 of formal-19-01-05 shows a screenshot of Applicant Data.
    The values of Applicant Data.Monthly.Income and Applicant Data.Monthly.Expenses are inverted, if the end result of executing the model is for decision Routing = "ACCEPT".

    In other words; currently the PDF document display as:
    Applicant Data.Monthly.Income = 10000 (ten-thousands)
    Applicant Data.Monthly.Expenses = 100000 (a-hundred-thousands)
    but actually it should be:
    Applicant Data.Monthly.Income = 100000 (a-hundred-thousands)
    Applicant Data.Monthly.Expenses = 10000 (ten-thousands)
    if the decision Routing should evaluate to "ACCEPT".

    Also, check spelling of "Stragegy" in Fig 11.30

  • Reported: DMN 1.2b1 — Wed, 10 Oct 2018 13:13 GMT
  • Updated: Thu, 11 Apr 2019 00:46 GMT
  • Attachments:

"get value" and "get entries" function not in built-in functions list

  • Key: DMN13-122
  • Status: open  
  • Source: Montera Pty Ltd ( Greg McCreath)
  • Summary:

    The above section mentions to two context-related functions "get value" and "get entries" that are not in the built in functions list. Are they meant to be there?

  • Reported: DMN 1.2b1 — Thu, 15 Nov 2018 08:18 GMT
  • Updated: Thu, 11 Apr 2019 00:46 GMT

Lack of visual notation for processing of / iteration over lists in FEEL


Add built-in functions to support Allen's interval algebra

  • Key: DMN13-139
  • Status: open  
  • Source: Trisotech ( Denis Gagne)
  • Summary:

    Allen's interval algebra defines possible relations between two intervals.
    Namely:
    before
    meets
    overlaps
    finishes
    includes
    starts
    coincides
    after
    metBy
    overlappedBy
    finishedBy
    during
    finishes

    Some more info available here: https://en.wikipedia.org/wiki/Allen%27s_interval_algebra

  • Reported: DMN 1.2b1 — Wed, 6 Feb 2019 21:26 GMT
  • Updated: Tue, 2 Apr 2019 00:09 GMT

Fix grammar rule references in FEEL grammar

  • Key: DMN13-140
  • Status: open  
  • Source: Red Hat ( Edson Tirelli)
  • Summary:

    As discussed in the RTF call on Feb 5th, we need to fix:

    1.Refs to grammar rules at end of ch9 are incorrect (change 14 to 12 and check others)
    2. grammar rule 14 in ch10 is unused and should be removed
    3. UnaryTests UML class is missing from the spec (it is shown on one diagram not the defining occurrence
    Need to specify this MM class and point to the correct unary tests grammar rule that defines its syntax (this will be different for FEEL and SFEEL)

  • Reported: DMN 1.2b1 — Tue, 5 Feb 2019 17:53 GMT
  • Updated: Tue, 2 Apr 2019 00:08 GMT

Allegedly bug in Table Table 40 Examples of equivalence and conformance relations

  • Key: DMN13-141
  • Status: open  
  • Source: Red Hat ( Matteo Mortari)
  • Summary:

    The DMNv1.2 spec reports these two lines examples:

    type1 type2 equivalent to conforms to
    type([{"id": 1,"name":"Peter", "age": 45}])
    
    type(Decision3)
    
    True True
    type(Decision4)
    
    type(Decision3)
    
    True True

    However concerning the first referenced line, type1

    type([{"id": 1,"name":"Peter", "age": 45}])
         ^
      by following the syntax used in table 39 takes the form of the type:
    
    list<context<"id": number,"name": string, "age": number>>
    

    and type2:

    type(Decision3)
    
      by following the syntax used in table 39 takes the form of the type:
    
    context<"id": number,"name": string, "age": number>
    

    So in the first referenced line it is asserted type1 is Equivalent to type2, but a list and a context are not Equivalent by the rule described in section 10.3.2.9.1 Type Equivalence

    Similarly for the second referenced line, type 1:

    type(Decision4)
    
      by following the syntax used in table 39 takes the form of the type:
    
    list<context<"id": number,"name": string, "age": number>>
    

    As for the ItemDefinition with the isCollection="true" which therefore obliges the definition that:

    IsCollection: Boolean Setting this flag to true indicates that the actual values defined by this ItemDefinition are collections of allowed values.

    So again by the section 10.3.2.9.1 Type Equivalence there are no "iff" rules explicited which would make a LIST Equivalent to a CONTEXT.

    Analogous issue for the reported values of Conformance.

    Can you kindly verify and clarify if needed, please?

  • Reported: DMN 1.2b1 — Fri, 1 Feb 2019 14:07 GMT
  • Updated: Tue, 2 Apr 2019 00:08 GMT
  • Attachments:

Spec does not clarify meaning of hex value

  • Key: DMN13-142
  • Status: open  
  • Source: fujitsu america ( keith swenson)
  • Summary:

    Rule #66 on page 111 says that a character in a string can be expressed as:

    "\u", hex digit, hex digit, hex digit, hex digit

    For example "\uD83D"

    That is, exactly four hex digits. I believe the intent is that FEEL only allows exactly four digits, and does not allow the kinds of expressions that we see in the EBNF.

    What is never specified is the exact meaning of that hex value. There are two possibilities:

    (a) Is that value a Unicode code point? In this case it is easy, the hex value is the code point value, however because you are limited to 64K characters, and not the 1.1M character range normally considered, and not even the values that are mentioned in the spec as having significance.

    (b) Or is it a UTF-16 code value? UTF-16 has encoding rules about values in the surrogate character range. In UTF-16 a high-surrogate-code value must be followed by a low-surrogate-code value or else the sequence of values is invalid and undefined. Using surrogate characters you can address the entire 1.1million characters but the user is required to understand about surrogate pairs.

    The spec never mentions that UTF-16 encoding is required! It always uses "Unicode" and talks about "characters" and "code points". It does not mention anything about surrogate pairs. It never says that these values a "just like Java" or any other UTF-16 implementation.

    Page 124 says that the FEEL string value is the same as java.lang.String. Should we infer from that that internal representations must be in UTF-16? however it also says that it is equivalent to an XML string (which is NOT constrained to UTF-16) and PMML string which I looked up and seems to be based on XML. XML allows characters to be expressed as &#nnnn ; That is an ampersand, a hash, a decimal number, terminated by a semicolon. In this case, the decimal value is the actual code point, and not the UTF-16 value. So page 124 does not say unambiguously that Java defines the string values that can be used.

    Unicode is mentioned only in three places: on page 108 (about EBNF character ranges), page 111 that tokens are a sequence of unicode characters, page 114 in an example.

    While it might be nice to be a "code point", the syntax clearly limits you to four digits leaving you no way to express larger code point values. If it was a code point you would be limited to only specifying 64,000 character (minus several thousand code points that not allowed for various reasons).

    The easiest repair is to state clearly that the \u notation assumes that UTF-16 is being used to encode the strings, and that UTF-16 rules must be used when specifying hex values for characters.

    I believe most implementations to date have assumed that these are UTF-16 code unit values. That is what Java does. That is what JavaScript does. I don't know of any environments that do anything different for this kind of expression.

  • Reported: DMN 1.2b1 — Fri, 8 Feb 2019 18:33 GMT
  • Updated: Tue, 2 Apr 2019 00:07 GMT

Should add a new unicode escape syntax

  • Key: DMN13-143
  • Status: open  
  • Source: fujitsu america ( keith swenson)
  • Summary:

    On page 110, rule #66 gives these escape sequences:

    string escape sequence = "\'" | "\"" | "
    " | "\n" | "\r" | "\t" | "\u", hex digit, hex digit, hex digit, hex digit;

    Using the hex character value notation "\uD41A" you can only four hex digits which is not enough to specify the entire Unicode character range. The spec specifically mentions that much higher values are allowed, and there should be a standard way to specify them without having to use the cryptic surrogate character pairs.

    This suggestion is to add braces to allow variable length hex values in exactly the way that JavaScript allows:

    "\u

    {1F40E}

    "

    This is character 128,014 in the unicode set. To specify this character using surrogate pairs you would have to use: "\uD83D\uDC0E" which is complicated and confusing and is currently subject to discussion on whether this is valid or not within the current spec.

    "A" = "\u

    {41}

    "

    "è" = "\u

    {E8}

    "

    "査" = "\u

    {67FB}

    "

    "" = "\u

    {1F407}

    " (Jira seems to crash if I inlcude this character)

    It is nice because you actually use the Unicode code point value, and because of the braces you can specify a variable number of hex digits so the entire Unicode set can be easily addressed. The precidence for this syntax is set by JavaScript (

    https://www.ecma-international.org/publications/files/ECMA-ST/Ecma-262.pdf

    See page 218 where it defines this (slightly translated):

    UnicodeEscapeSequence ::
    \u Hex4Digits
    \u

    { CodePoint }

    This will not conflict with any existing implementation since the opening brace was not allowed in earlier implementations. The new allowed syntax could be used in DMN 1.3 and higher.

  • Reported: DMN 1.2b1 — Fri, 8 Feb 2019 19:06 GMT
  • Updated: Tue, 2 Apr 2019 00:07 GMT

Support for function types in metamodel and XSD

  • Key: DMN13-145
  • Status: open  
  • Source: Goldman Sachs ( Octavian Patrascoiu)
  • Summary:

    The DMN metamodel & the XSD schema do not support definition of function type. For example, a construction as the one below is not supported:

    <functionDefinition name='add_type' returnType='number'>
             <parameters>
                    <param name='a' typeRef='number'>
                    <param name='b' typeRef='number'>
            </parameters>
    </functionDefinition>
    
  • Reported: DMN 1.2b1 — Fri, 22 Feb 2019 11:57 GMT
  • Updated: Tue, 2 Apr 2019 00:06 GMT

Clarification on DMN case sensitivity of timezones

  • Key: DMN13-149
  • Status: open  
  • Source: Montera Pty Ltd ( Greg McCreath)
  • Summary:

    DMN spec refers to usage of iana timezones. iana does not specify that timezones are case-sensitive - that is up to the implementation. https://data.iana.org/time-zones/theory.html: re zone naming:

    "Do not use names that differ only in case. Although the reference implementation is case-sensitive, some other implementations are not, and they would mishandle names differing only in case."

    This issue is seeking clarification via the spec as to whether DMN's usage of time zones permits case insensitivity such that "etc/utc" is the same zone as "Etc/UTC" ... or not.

  • Reported: DMN 1.2 — Sat, 16 Mar 2019 01:12 GMT
  • Updated: Tue, 2 Apr 2019 00:04 GMT

properly define type(e)

  • Key: DMN13-114
  • Status: open  
  • Source: Oracle ( Gary Hallmark)
  • Summary:

    In some places the spec uses type(e) and other places type(e). These are different. The former provides a type-checking function that can validate a FEEL expression e without input data values (although some kind of scope is needed for disambiguation). The latter simply returns the datatype of the semantic domain element e. The former is more useful to implementors, but more work to specify. Essentially, all the semantic mapping tables need a new column to specify the result type given the input types, for each FEEL operator and builtin. The latter is a matter of generalizing Table 39. It must cover cases such as type([0,false]). It should be clear that type(e) as a function must return the most specific type (and there must be only 1), but informally the types also include those that are conformed to, so for example, [1,2,3] has types list<number>, list<Any>, Any.

  • Reported: DMN 1.2 — Tue, 27 Nov 2018 22:31 GMT
  • Updated: Mon, 1 Apr 2019 23:58 GMT

Wrong example in chapter "10.3.1.5"

  • Key: DMN13-133
  • Status: open  
  • Source: Red Hat ( Matteo Mortari)
  • Summary:

    The specification in chapter "10.3.1.5 Contexts, Lists, Qualified Names, and Context Lists"

    presents the following example:

    [{a: [{b: 1}, {b: [2.1, 2.2]}]}, {a: [{b: 3}, {b: 4}, {b: 5}]}].a.b =
    [[{b: 1}, {b: [2.1, 2.2]}], [{b: 3}, {b: 4}, {b: 5}]].b =
    [[1, [2.1, 2.1]],[ 3, 4, 5]]
    

    However line 2 is wrong since DMNv1.2 dropped the equivalence that

    a=[a]
    

    therefore line 2 is problematic:

    [[{b: 1}, {b: [2.1, 2.2]}], [{b: 3}, {b: 4}, {b: 5}]].b =
     ^ b property is not available here
    

    as at the cursor position is not a context but two items of the root list.

    It is proposed to replace the example as follows:

    [{a: {b: 1}}, {a: {b: [2.1, 2.2]}}, {a: {b: 3}}, {a: {b: 4}}, {a: {b: 5}}].a.b =
    [{b: 1}, {b: [2.1, 2.2]}, {b: 3}, {b: 4}, {b: 5}].b =
    [1, [2.1, 2.1], 3, 4, 5]
    
  • Reported: DMN 1.2b1 — Sat, 26 Jan 2019 09:34 GMT
  • Updated: Thu, 14 Mar 2019 00:24 GMT

Make explicit reference to sample standard deviation

  • Key: DMN13-131
  • Status: open  
  • Source: Red Hat ( Matteo Mortari)
  • Summary:

    The specification in chapter "10.3.4.4 List functions" for built-in function stddev does not explicit if it's meant to be population or sample standard deviation.
    However based on the example provided "stddev( 2, 4, 7, 5 ) = 2.0816659994661" would indicate it is meant to be the sample standard deviation --which is undefined for a single 1 sample value

    In order to be explicit, it is suggested to change the table entry as:

    Name(parameters) Parameter Domain Description Example
    stddev( list )
    stddev( n 1 , ..., n n )
    list is a list of number. n 1 ... n n are numbers. Returns the
    (sample) standard deviation of the list of numbers. If the list is empty,
    returns null. If the list contains only one number item, if n is a single number returns null.
    stddev( 2, 4, 7, 5 ) =
    2.0816659994661
    stddev( [ 47 ] ) = null
    stddev( 47 ) = null
    stddev( [ ] ) = null
  • Reported: DMN 1.2b1 — Fri, 18 Jan 2019 15:30 GMT
  • Updated: Thu, 14 Mar 2019 00:24 GMT

Disambiguation for Modulo / Remainder function

  • Key: DMN13-124
  • Status: open  
  • Source: Red Hat ( Matteo Mortari)
  • Summary:

    The spec defines "modulo" FEEL built-in function as: "the remainder of the division of dividend by divisor"
    However, this might be subject to ambiguity in the case the Divisor or Dividend are negative, as also mentioned by Wikipedia page which list examples out of several programming languages and systems: https://en.wikipedia.org/wiki/Modulo_operation by saying that "When either a or n is negative, the naive definition breaks down and programming languages differ in how these values are defined".

    FEEL aims to be a Friendly Enough expression language, and especially thinking about DMN practitioners who might be used to Spreadsheet based systems might find misleading if the definition of the FEEL "modulo" gets bind to the Java (default) definition, the following table illustrate the difference:

    Dividend Divisor MOD() from Microsoft Excel, Google Sheets, LibreOffice Calc, Wolfram Alpha, etc. Java % or BigDecimal#remainder or other languages default
    10 4 2 2
    10 -4 -2 2
    -10 4 2 -2
    -10 -4 -2 -2

    or to other implementation languages where the definition of Modulo/Remainder is not explicit, or the default one is not consistent with Spreadsheet default one.

    It is proposed therefore to change the specification in 10.3.4.5 Numeric functions Table 70 for the FEEL "modulo" built-in function
    FROM: "Returns the remainder of the division of dividend by divisor."
    TO: "Returns the remainder of the division of dividend by divisor. In case either dividend or divisor is negative, the result has the same sign of the dividend."

    This would avoid ambiguity by making a clear definition of what should be the sign in case either of the operands are negative.
    This should make this consistent with Spreadsheet based system result of "MOD()" expression, which should address being Friendly Enough for DMN practitioners and DM analyst.
    This would not make the result the same as the default of Java % operator or BigDecimal#remainder, but Java based implementation/Vendor can trivially address the result to be compliant with the spec.

  • Reported: DMN 1.2b1 — Fri, 4 Jan 2019 18:34 GMT
  • Updated: Thu, 14 Mar 2019 00:24 GMT

Minor typos in the FEEL grammar

  • Key: DMN13-120
  • Status: open  
  • Source: Goldman Sachs ( Octavian Patrascoiu)
  • Summary:

    Typo in rule

    51. comparison =
    a.expression , ( "=" | "!=" | "<" | "<=" | ">" | ">=" ) , expression |
    b.expression , "between" , expression , "and" , expression |
    c.expression , "in" , positive unary test ;
    d.expression , "in" , " (", positive unary tests, ")" ;

    c. should have | at the end not ;

    We should replace non-terminal Boolean literal with boolean literal for consistency.

  • Reported: DMN 1.2b1 — Sat, 8 Dec 2018 19:36 GMT
  • Updated: Thu, 14 Mar 2019 00:24 GMT
  • Attachments:

Ambiguty for the source/target of DMNEdge when there is multiple depictions of its source and target

  • Key: DMN13-109
  • Status: open  
  • Source: Trisotech ( Denis Gagne)
  • Summary:

    DMN DI allows to depict element more than once. When drawing a diagram, tools need to check graphically the way points to know to which DMNShape a DMNEdge is actually connected to.

  • Reported: DMN 1.2 — Mon, 26 Nov 2018 22:50 GMT
  • Updated: Thu, 14 Mar 2019 00:24 GMT
  • Attachments:

example shows literal inline function definition whereas grammar says function definitions only in boxed expressions.

  • Key: DMN13-121
  • Status: open  
  • Source: Montera Pty Ltd ( Greg McCreath)
  • Summary:

    The spec example shows a function definition inline in a literal expression using sort(). My take on the FEEL grammar spec is that a function definition can only exist inside a boxed expression, not inside a literal expression. A function definition inside a literal expression whose body has names with spaces or additional characters makes the parsing of the entire expression before execution darn hard - we'll I haven't figured it out anyways.

    In the specific case of the sort function, the type of the 'list' parameter may only be known at execution time, and thus the types of the arguments to the 'precedes' function can only be known at execution time - that is, when actually executing the sort. And to execute a sort, you need to pass it its arguments - which means a parsed function definition. If that function definition has names with spaces, then parsing can't be done until the types are known - during the sort execution. A little bit chicken an egg.

    But, if I read the spec correctly, you should not be able to have a function definition inside a literal expression. In which case, it is parsed separately to its invoking function and the above is not an issue.

    As a note, the given example and some tests in the TCK (which I am not sure should be there) involve simple params or simple names and can be parsed. But the scenario above is not covered by the TCK.

    Happy to be guided otherwise. An all advice appreciated.

  • Reported: DMN 1.2b1 — Thu, 15 Nov 2018 08:00 GMT
  • Updated: Thu, 14 Mar 2019 00:24 GMT

Inconsistency DMNv1.2 dropping [a]=a and get entries example

  • Key: DMN13-134
  • Status: open  
  • Source: Red Hat ( Matteo Mortari)
  • Summary:

    Since DMNv1.2 the spec dropped the equivalence of:

    [a] = a
    

    because it does not apply to the statement that

    a singleton list L, when used in an expression where a list is not expected, behaves as if L[1] is written.

    So the expression

    [a] = a
    

    on DMNv1.2 is expected to return false.

    However, in section 10.3.2.6 Context of the spec, it provides the following statement for the get entries function:

    To retrieve a list of key,value pairs from a context m, the following built-in function may be used: get entries(m).
    For example, the following is true:

    get entries({key 1 : "value 1 "})[key="key 1 "].value = "value 1 "
    

    BUT

    get entries({key1 : "value1"})[key="key1"].value = "value1"
    
      by substitution:
    
    [ { key : "key1", value : "value1" } ][key="key1"].value = "value1"
    [ { key : "key1", value : "value1" } ].value = "value1"
    [ "value1" ] = "value1"
    

    according to DMNv1.2 should be false

    By the same principle that the DMNv1.2 for the following literal expression:

    [123] = 123
    

    on DMNv1.2 is expected to be false

  • Reported: DMN 1.2b1 — Wed, 30 Jan 2019 14:43 GMT
  • Updated: Tue, 12 Mar 2019 16:38 GMT

"instance of" not possible with some built-in functions

  • Key: DMN13-123
  • Status: open  
  • Source: Montera Pty Ltd ( Greg McCreath)
  • Summary:

    some built in functions are overloaded in that they can have multiple signatures. So, say, performing an "instance of" to compare against the function "min" is meaningless as the signature is not known unless it is invoked.

    Unless the type system is to take into account overloaded functions?

  • Reported: DMN 1.2b1 — Thu, 15 Nov 2018 08:15 GMT
  • Updated: Tue, 5 Mar 2019 17:25 GMT

Remove the limitation that the second operand of exponentiation be an integer

  • Key: DMN13-111
  • Status: open  
  • Source: Trisotech ( Denis Gagne)
  • Summary:

    Table 55: Semantics of exponentiation limits the second operand to be an integer. It allow any number.

  • Reported: DMN 1.2b1 — Tue, 27 Nov 2018 14:10 GMT
  • Updated: Thu, 13 Dec 2018 00:17 GMT

Remove reference to SQL and PMML three value logic to eliminate misinterpretation

  • Key: DMN13-106
  • Status: open  
  • Source: Trisotech ( Denis Gagne)
  • Summary:

    The spec says: Three-valued logic (true, false, null) based on SQL and PMML
    This statement can lead to misinterpretation (given their understanding of the SQL and/or PMML three value logic) for nothing given that we define the semantic of the FEEL three Value logic clearly below.

  • Reported: DMN 1.2b1 — Tue, 20 Nov 2018 17:12 GMT
  • Updated: Thu, 13 Dec 2018 00:17 GMT

Allow representation of black-box Decision Service

  • Key: DMN13-90
  • Status: open  
  • Source: Decision Management Solutions ( James Taylor)
  • Summary:

    As DMN gets used to produce publicly available decision services we will need some way to represent a decision service that the modeler cannot see into. They know its a side-effect free, stateless decision service and know its signature so they can add a decision to their own model that is implemented by it but they don't know what decisions, BKMs, knowledge sources etc were used to produce it. There is currently no way to do this - a decision service can be shown collapsed but only if the model "knows" what the expanded version looks like. It feels like it would be useful to do so.

  • Reported: DMN 1.2 — Thu, 27 Sep 2018 01:04 GMT
  • Updated: Tue, 23 Oct 2018 16:37 GMT

Fix interchange of links to objects in BPMN/BMM

  • Key: DMN13-91
  • Status: open  
  • Source: Decision Management Solutions ( James Taylor)
  • Summary:

    The current spec uses objects from BMM and BPMN. However it is not at all clear how links to these objects, and the objects at the end of the links, should be interchanged. Does the DMN file contain a snippet of BPMN? Should a separate BPMN file be generated and then referenced? If we are going to have these links then we need to show/explain how to interchange them both with tools that only support DMN (and so only have a few BPMN or BMM objects) and with those that support DMN/BPMN/BMM.

  • Reported: DMN 1.2 — Thu, 27 Sep 2018 01:07 GMT
  • Updated: Tue, 16 Oct 2018 16:47 GMT