1. CQL 2018May Ballot Reconciliation

2. Ballot Level and Iteration
Ballot Summary
Name
Ballot Level and Iteration
Affirmative Votes
Negative Votes
Abstains
No Vote Returned
Total Pool Size
Quorum
Affirmatives Needed
HL7 Cross-Paradigm Specification: Clinical Quality Language, Release 1 (PI ID: 1108) S3 70 11 65 26
172
84.88% 49
Category
Count
3VL 8
Arithmetic Operators 1
Clarification 12
Date/Time Arithmetic 27
Duplicate
ELM
Equality/Equivalence 11
Errata 18
Evaluation
Examples 6
FHIRPath
Formatting 35
Guidance 15
Interval Operators 9
Language 4
Message 2
Navigation
Promotion 13
Query Question
String Operators 3
Terminology
Typo
Updates
Website Comment 24
Amalgamation Results
Ballot Count 8
Line Count
225
In Person 40
Negative 74
Affirmative Total
150
Affirmative-A 2
Affirmative-S 96
Affirmative-T 30
Affirmative-Q 19
Affirmative-C 3
No Vote 1

3. Disposition Status (as of 6/13/2018)
Count
Withdrawn 1
Blank 97
Not persuasive 12
Not persuasive with mod
Persuasive
108
Persuasive with mod 6
Primary Questions to resolve:
Query Change Proposal
Equality/Equivalence Behavior
List Membership/Duplicate Detection
Date/DateTime Operations
Interval Promotion

4. Query Change Proposal
Should the "from" keyword be required for all queries
Ballot says "no" unless it is done backwards compatibly
Only 4 responses, all from toolsmiths using the current stack, not authors or toolsmiths that use a different stack
Strawman Proposal
Introduce from as an optional keyword for single-source queries
Add a translator option "require-from-keyword" to require it for all queries
Needs to be vetted in the translator before we can be sure it will work

5. Equality/Equivalence Behavior
Detailed in comments #219, #220
Date/Time Comparison is performed at the unit with the most precision of either input.
For equality, null will only be returned if the inputs have different levels of precision
For equivalence, if equality would return null, equivalence returns false
Tuple/Object Comparison ignores elements that are null in both inputs.
Null will only be returned if the inputs have different null elements
Provides a basis for proposed resolutions for the Equality/Equivalence category

6. List Membership/Duplicate Detection
Detailed in Comment #221
List membership and duplicate detection would use Equality semantics rather than Equivalence semantics throughout
Aligns with FHIRPath
One issue is ValueSet membership currently relies on Equivalence behavior of Codes, rather than Equality

7. Date/DateTime Operations
Many of the resolutions will depend on the Equality/Equivalence question
Several comments related to the use of the Date/DateTime type as result/operand in
Literals
Today()
Age calculations
Subtract overloads for DateTime/Date
Possibly returning a list of durations (e.g. 2 years, 3 months, 5 days)

8. Interval Promotion/Demotion
Concern about unintended consequences of Interval Promotion/Demotion
Mitigation is
Intervals are not as pervasive as lists, especially in queries, so there is less opportunity for unintentional promotion (i.e. it only occurs in timing phrases and interval operators)
Added translator options to separately control interval vs list promotion and demotion
Can always require strict use of date/time and interval operators rather than enabling the translator option

9. Interval Operators
Concern about difference between overloads in ELM versus signatures enabled by implicit conversion and promotion/demotion in CQL
Mitigation proposed in comments #224 and #225
Better ELM documentation overall (ELM category comments)
Document mixed type overloads on interval operators that are enabled by implicit conversion or promotion/demotion

10. Next Steps
Discuss these straw men with submitters and stakeholders to get consensus around the primary questions for the ballot
Prepare dispositions based on the consensus views
Prepare block votes for the non-controversial categories:
Clarification, Errata, Examples, Formatting, Typo, Updates, Website Comment