29683 2016-06-02 09:46:43 +0000 [XP31] Map lookup through function-call syntax does not explain what happens if the key does not exist 2016-07-20 13:58:45 +0000 1 1 1 Unclassified XPath / XQuery / XSLT XPath 3.1 Member-only Editors Drafts PC Windows NT CLOSED FIXED P2 minor --- 1 abel.braaksma jonathan.robie mike public-qt-comments oldest_to_newest 126645 0 abel.braaksma 2016-06-02 09:46:43 +0000 Section 3.11.1.2 Map Lookup using Function Call Syntax in FO31 does not explain what happens if 1) the key does not exist (should it through an error, or behave like map:get?) 2) the key is not comparable using the collation (behave like map:get?) Perhaps we should normatively link this section to the semantics of map:get, or conversely, move the semantics of map:get to this section and link back from map:get to this section. Alternatively, using this syntax may raise an error for non-existing map keys, but I doubt that was the intend. Note: sections 3.11.3.1 Unary Lookup and 3.11.3.2 Postfix Lookup do not seem to explain this either. 126646 1 abel.braaksma 2016-06-02 10:06:15 +0000 Note, the example in FO31 section 17.5.3 fn:json-to-xml suggests that $m(x), where $m is a map, should return the empty sequence. Checking this code was what brought me to reporting this, as I had expected map:exists($c0chars, $char) in there somewhere. This rule is implied from the lines with $replacement in the code below: .... let $c0chars := map { '\u0000':'[NUL]', '\u0001':'[SOH]', '\u0002':'[STX]', ... '\u001E':'[RS]', '\u001F':'[US]' }, $replacement := $c0chars($char) return if (exists($replacement)) .... 126647 2 mike 2016-06-02 10:43:36 +0000 The reference in Section 3.11.1.2 Map Lookup using Function Call Syntax in FO31 should be to 3.11.1.2 in *XP31*. I agree that the semantics of $M($K) should be defined as equivalent to map:get($M, $K). 126696 3 jonathan.robie 2016-06-07 15:22:03 +0000 (In reply to Michael Kay from comment #2) > I agree that the semantics of $M($K) should be defined as equivalent to > map:get($M, $K). Yes. And for arrays, $A($K) should be defined as array:get($A, $K). 126765 4 jonathan.robie 2016-06-14 15:36:46 +0000 Resolved by accepting comment #2 and comment #3. 127006 5 abel.braaksma 2016-07-20 13:58:45 +0000 Checked, looks good, thanks.