19626 2012-10-19 08:55:29 +0000 [XQ31] Awkward option declarations 2014-04-22 15:43:24 +0000 1 1 1 Unclassified XPath / XQuery / XSLT XQuery 3.1 Working drafts PC Windows NT CLOSED FIXED P2 normal --- 1 tim jonathan.robie mike public-qt-comments oldest_to_newest 76663 0 tim 2012-10-19 08:55:29 +0000 Consider the following query. import schema namespace s = "http://www.w3.org/XQueryTest/RequireProhibitF eature"; declare function local:foo() as schema-element(s:foo) { ... } declare option prohibit-feature "schema-aware"; local:foo() It is not until we are well into parsing that the option prohibiting use of import schema is encountered. This is quite annoying. Consider also a processor which has schema awareness disabled by default. import schema namespace s = "http://www.w3.org/XQueryTest/RequireProhibitF eature"; declare function local:foo() as schema-element(s:foo) { ... } declare option require-feature "schema-aware"; local:foo() It is not until we are well into parsing that the option enabling use of import schema is encountered. This is similarly annoying. 76664 1 mike 2012-10-19 09:08:13 +0000 Another example of the same effect occurs when the higherOrderFunction feature is disabled after a function or variable declaration that makes use of it. However, I'm inclined to live with it. In general, we allow forwards references; it's a hassle for implementors, but that's the job that implementors are paid for. 76667 2 tim 2012-10-19 09:16:19 +0000 There's also a usability issue. It's natural to write the require/prohibit before the feature is used - but this is grammatically incorrect. Other examples include use of validate expressions in a function, or use of fn:serialize with serialization disabled. That means it's awkward for every XQuery 3.0-defined feature except static typing. 76673 3 tim 2012-10-19 11:02:05 +0000 Additionally, I don't find this construct particularly intuitive. Without a detailed reading of the specification, I'd expect: declare option prohibit-feature "higher-order-function"; declare option require-feature "all-optional-features"; either a) to complain that the higher-order-function feature is both prohibited and required (since higher-order-function is in the set of all optional features), OR b) to disable the higher-order-function feature and then re-enable it. 77293 4 jonathan.robie 2012-10-29 15:51:26 +0000 The Working Group has decided not to change this in XQuery 3.0. Feel free to open this against 3.1 as a potential requirement. 77386 5 tim 2012-10-30 09:54:16 +0000 Reopening as a potential change for XQuery 3.1. I suggest something along the lines of [6] Prolog ::= ((DefaultNamespaceDecl | NamespaceDecl) Separator)* ((OptionDecl) Separator)* ((DefaultNamespaceDecl | Setter | NamespaceDecl | Import) Separator)* ((ContextItemDecl | AnnotatedDecl | OptionDecl) Separator)* to permit option declarations to appear before schema/module imports. 104169 6 jonathan.robie 2014-04-22 15:43:01 +0000 We had no consensus to adopt this change. 104170 7 tim 2014-04-22 15:43:24 +0000 Happy to close.