QT4 CG Meeting 129 Minutes 2025-07-15

Regrets: DB, BTW.

• [ ] David J Birnbaum (DB)
• [X] Reece Dunn (RD)
• [X] Christian Grün (CG)
• [X] Joel Kalvesmaki (JK)
• [X] Michael Kay (MK)
• [X] Juri Leino (JLO)
• [X] John Lumley (JWL)
• [ ] Dimitre Novatchev (DN)
• [X] Wendell Piez (WP)
• [X] Ed Porter (EP)
• [ ] Bethan Tovey-Walsh (BTW)
• [X] Norm Tovey-Walsh (NW) Scribe. Chair.

Proposal: Accept the agenda.

Accepted.

Proposal: Accept the minutes of the previous meeting.

Accepted.

The next meeting is scheduled for 22 July 2025.

DB gives regrets.

(Items marked [X] are believed to have been closed via email before this agenda was posted.)

• [ ] QT4CG-082-02: DN to work with NW to come to agreement on the fn:ranks proposal
• [ ] QT4CG-112-01: JLO to propose a concrete example that uses “.” in a ~%method~s.
• [ ] QT4CG-116-01: Add a specific error code for unsupported options on doc and doc-available
• [ ] QT4CG-118-01: MK to make an incorrect type raise an error in #1906
• [ ] QT4CG-123-01: MK to do the set example in XQuery.
• [ ] QT4CG-127-01: NW to diagram the JTree representing arbitrary XDM content.
• [ ] QT4CG-128-01 CG to consider using “standard” or some other term instead of “regular” in the file: module.
• [ ] QT4CG-128-02 CG to investigate what to say about permissions.
• [ ] QT4CG-128-03 NW to compare the file: module against the equivalent XProc 3.1 steps

This section summarizes all of the issues and pull requests that need to be resolved before we can finish. See Technical Agenda below for the focus of this meeting.

declare record local:a(b as local:b?);
declare record local:b(a as local:a?);
() => local:a() => local:b()

Last week, we agreed to return to this with an eye towards accepting it unless there are objections.

See PR #2083: 2054 Generalized Path Expressions and PR #2031: 2025 JNodes

(I believe that #2083 subsumes #2031, so accepting #2083 should also close #2031.)

• MK: Just want to draw your attention to the fact that I responded to several comments.
  • … The mixed case names are now all lowercase
  • … Gunther Radamacher’s comment about needing to reserve more function names; we had both a type and a function called jnode(). I’ve renamed the type as jnode-type() but we may want to resolve that differently.
  • … The property names now use “..” instead of “¶”.
• CG: I think it’s a good idea to merge this PR; but it’s so huge.
  • … I think that transitive closure functions might need some revisions.
• NW: I think we should merge it.
• JK: I’d like to merge it, but I think we need to have a discussion about how definitions are worded.

Proposal: merge this PR.

Accepted.

This obsoletes #2031.

• JWL: Is it worth putting something on Slack that we’re making this big change.

See PR #2094

MK introduces the PR.

• MK: This is confined to a fairly small part of the XPath spec.
  • … I’ve moved things around a bit.
  • … The section begins with an example of something you didn’t used to be able to do.
  • … The new case is that an ExprSingle can be written without a : and it must return zero or more map items.

The example with employee has an error, it should be: { //employee ! {@id : .} }.

• JWL: Can you use a predicate?
• MK: Yes, I’ll add an example.
• JLO: One thing that struck me: the map key expression and map value expression are no longer used by the map constructor expression but are referenced elsewhere.
• MK: I thought I’d dropped all reference to them.
  • … Oh, you’re right. There are.

ACTION: QT4CG-129-01: MK to fix the remaining prose references to MapKeyExpr and MapValueExpr

Some discussion of why it was dropped. Avoiding lookahead was the goal.

• RD: With the key, if you have a sequence of values, are we handling the semantics of that?
• MK: The result of atomizing must be a single atomic item otherwise it’s a type error.
• JLO: I’d like to be able to put in a variable into a map and have it expand into key and value.
  • … Previously we said this shouldn’t be allowed because of substitutability
  • … But we’re so close now. Wouldn’t it be possible?
• MK: I’m not sure I understand the example.
• JLO: I want:

let $a := 1
let $m := { $a }

to return {"a": 1}

• MK: Substitutability certainly means you should be able to rename variables without changing expressions.
• CG: In this example, $a will be allowed and if it returns a map that will become a map.

Proposal: accept this PR.

Accepted.

See PR #2014

MK introduces the PR starting with the general rules about where XPath expressions occur in XSLT.

• MK: There is some reordering of sections.
  • … “Creating nodes and sequences” has moved into “Callable components”.
  • … Some examples have been added.

Proposal: accept this PR.

Accepted.

See PR #2019

Not ready yet.

See PR #2037

Needs to be reviewed.

See PR #2043

MK introduces this PR.

• MK: We introduced fn:apply-templates() largely so that we could use XPath array and map constructors and do apply templates in the middle.
  • … In implementing it, I realized there was a complication that wasn’t really adding any value: you could make it use the default mode from the static context.
  • … I don’t think we want to keep the default mode around in every dynamic context.
  • … Let’s make it compulsory to say what mode you want to apply templates in if you’re using the functional form.
  • … The effect is to remover #default from the list of available modes.
• JWL: Would this apply in an XPath expression that’s in an enclosed mode?
• MK Yes.

Proposal: accept the PR.

Accepted.

See PR #2011

MK introduces the PR.

• MK: This just updates the current table of rules to add some new constructs.
  • … The U-type of a choice item type is defined.
  • … The table and its description have been expanded.
  • … OtherwiseExpr has been added.
  • … Some notational changes have been made.
  • … StringTemplate has been added.
  • … ContextValueRef becomes a bit more complicated as a consequence of generalizing the context item.
  • … Partial Function Application has been added (with a TODO).
  • … Deep Lookup needs to be examined again
• MK: It doesn’t address streamability, it just updates the relevant static type information.
• JWL: Is adding jnodes going to be about adding map types?
• MK: No, they’re a new type.

Proposal: accept the PR.

Accepted.