29449 2016-02-11 22:35:05 +0000 [xslt 3.0] Streamability of $map($key) and $array($index) 2016-02-19 12:29:54 +0000 1 1 1 Unclassified XPath / XQuery / XSLT XSLT 3.0 Candidate Recommendation PC All CLOSED FIXED P2 normal --- 1 mike mike public-qt-comments oldest_to_newest 125001 0 mike 2016-02-11 22:35:05 +0000 In 19.8.8.10 Streamability of Dynamic Function Calls It would be useful to explain the effect of these rules on dynamic function calls where the "function" in question is a map or an array. Intuitively, if we know that the "base expression" (the function) is a map or an array, and the argument is motionless, then the dynamic function call itself is motionless; if we don't know (because the type analysis doesn't tell us), then we can't determine that the expression is guaranteed-streamable, and the user should be advised to write map:get($map, $key) or array:get($array, $index) instead; or perhaps to use the "?" lookup operator if XPath 3.1 is available. 125053 1 mike 2016-02-15 16:27:17 +0000 Resolution: add a note to the spec along the following lines: Note that in a dynamic function call $F($A), the operand usage of $F is inspection, so what is passed to $F has no direct bearing. As for $A, if we know that $F is a map or array, then we know that $A has usage absorption (because the inferred type is xs:anyAtomicType), and therefore passing a streamed node is OK (the result will be consuming), but if we don't know that $F is a map or array, then passing a streamed node will be roaming/free-ranging. So advice is users is: if you want it to be streamable, make sure $F is declared to be a map or array, or use an alternative construct such as $F?($A) (3.1) or map:get($F, $A). 125159 2 mike 2016-02-19 12:29:54 +0000 The spec has been updated along the lines agreed.