24378 2014-01-23 22:56:07 +0000 [XSLT30] xsl:on-empty on more instructions 2014-07-27 19:08:08 +0000 1 1 1 Unclassified XPath / XQuery / XSLT XSLT 3.0 Last Call drafts PC Windows NT CLOSED FIXED P2 normal --- 1 abel.braaksma mike cmsmcq public-qt-comments oldest_to_newest 98964 0 abel.braaksma 2014-01-23 22:56:07 +0000 This was briefly mentioned in [1] and discussed earlier at the July 11, 2013 telcon [2]. The idea was to extend xsl:on-empty at least to all node-construction instructions for reasons of usability and orthogonality. Other conclusions from that mail: (a) the expression in the on-empty attribute must be type-consistent with the instruction it appears on. For example, on an LRE the on-empty expression must return an element or nothing. (b) specifically on xsl:copy, the condition should be based on the emptyness of the constructed element/document, not the emptiness of the selected element/document This is also relevant to related bugs bug-24142 and bug-24140. [1] https://lists.w3.org/Archives/Member/w3c-xsl-wg/2014Jan/0004.html [2] https://lists.w3.org/Archives/Member/w3c-xsl-wg/2013Jul/0060.html (minutes) 100171 1 cmsmcq 2014-02-10 16:25:57 +0000 We discussed this issue at the Prague face to face. On consideration, our inclination was not to extend on-empty to further elements, but indeed to cut it back from some places which allow it now. The current semantics of on-empty for xsl:copy make it mean different things in different cases, which is confusing to some WG members and potentially problematic for implementors. We discussed a proposal to allow on-empty only in cases where the node being constructed can have children (is an element or a document node). One WG member found the semantics on xsl:copy confusing enough that he wanted to eliminate it there and allow it only on literal result elements, xsl:element, and xsl:document (etc.) We didn't feel we had a strong enough consensus to make a binding decision at the moment, though, given that the spec is in Last Call. We may wish to come back to this on another day, earlier in the day. 109322 2 mike 2014-07-27 19:07:55 +0000 On 24 July 2014 the WG decided that the [xsl:]on-empty attribute should apply only to literal result elements, xsl:element, and xsl:copy, and that in the case of xsl:copy it should apply only when the node being copied is an element node. The reasons for this are that (a) the major use cases for on-empty are concerned with construction of element nodes; (b) the concept of "emptiness" for elements and for nodes such as attributes is quite different, and overloading the concept gets messy, especially in the case of xsl:copy where the different meanings are mixed in one instruction.