29743 2016-07-20 05:07:06 +0000 XPath 3.1 maps recursive descent 2016-09-23 08:43:09 +0000 1 1 1 Unclassified XPath / XQuery / XSLT XPath 3.1 Working drafts PC All RESOLVED FIXED P2 normal --- 1 jorge.williams jonathan.robie andrew_coleman mike public-qt-comments oldest_to_newest 126991 0 jorge.williams 2016-07-20 05:07:06 +0000 We use JSONPath (http://goessner.net/articles/JsonPath/) along side of XPath, when working with JSON data. Now that XPath supports maps and JSON, I've started evaluating whether it may be worth consolidating around XPath exclusively. This would certainly make our lives easier especially as JSONPath implementations vary wildly. One feature that appears to be missing, but which is used quite often by our lazy developers is recursive decent ( .. in JSONPath). Notice the examples here: http://goessner.net/articles/JsonPath/ it's a bit of a challenge to replicate them with XPath 3.1. I've created a function in XQuery which I believe captures what JSONPath is doing and it looks like this: declare function r:d($m as item()) as item()* { let $funs := $m?*[. instance of map(*) or . instance of array(*)] let $mps := $funs[. instance of map(*)] return ($mps, $funs ! r:d(.)) }; Given that I can replicate all of the examples : | Description | JSONPath | XPath 3.1 | |------------------------------------+-------------------------+-------------------------------------| | All of the authors of a book | $.store.book[*].author | $_?store?book?*?author | | All authors | $..author | r:d($_)?author | | All things in the store | $.store.* | $_?store?* | | The price of everything in a store | $.store..price | r:d($_?store)?price | | The third book | $..book[ 2 ] | r:d($_)?book?3 | | The last book in order | $..book[(@.length-1)] | r:d($_)?book?*[position() = last()] | | | $..book[-1:] | | | The first two books | $..book[0,1] | r:d($_)?book?(1, 2) | | | $..book[:2] | r:d($_)?book?(1 to 2) | | Filter all books with isbn number | $..book[?(@.isbn)] | r:d($_)?book?*[?isbn] | | Filtar all books cheaper than 10 | $..book[?(@.price< 10)] | r:d($_)?book?*[?price < 10] | | All members of JSON structure | $..* | r:d($_) | Defining a function to do this doesn't seem right though. I must be missing something...or there is a gap. Thanks. 127310 1 mike 2016-09-06 19:28:13 +0000 Thank you for this usability feedback on the specification. After some consideration, the working group decided that a good part of the requirement could be met with a new function map:find($input as item()*, $key as xs:anyAtomic) as array(*) which searches $input recursively looking into contained maps at any depth to find an entry with key $key, and returning the associated values as members of the result array. This clearly doesn't satisfy all these examples but we felt it had the right blend of simplicity and capability, given how close we are to finishing. New syntax at this stage was felt to be far too risky. The WG has approved an outline sketch of the specification and will move on to consider the final proposed specification. 127511 2 andrew_coleman 2016-09-23 08:43:09 +0000 The function map:find() is available to review in the editor's draft of the F&O spec: https://www.w3.org/XML/Group/qtspecs/specifications/xpath-functions-31/html/#func-map-find Marking this bug resolved/fixed. Many thanks for raising this issue.