- From: Michael Kay <mhk@mhk.me.uk>
- Date: Fri, 20 Feb 2004 19:13:20 -0000
- To: "'Stephen Buxton'" <Stephen.Buxton@oracle.com>, <public-qt-comments@w3.org>
> SECTION 2: Basics > > The language should allow for nested sequences. Nested > sequences (a.k.a sequences of sequences) will help in > returning a set of related values easily. The current > mechanism requires one to put those values inside an XML > element which removes node identities, typing etc. > > Allowing nested sequence in later versions might be quite > hard because of implicit rules governing atomization, > normalization and concatenation of sequences. > Actually, allowing nested sequences isn't impossible to graft on. You can do it by defining a third kind of item: a sequence-reference. Then you just need a pair of functions to create a reference to a sequence and to dereference a seqref; and of course you need to review all the existing functions and operators to say what they do when they encounter a seqref; and of course you need some enhancements to the type system. Which means that it's probably worth allocating a couple of years to the task. Michael Kay
Received on Friday, 20 February 2004 14:12:37 UTC