Re: Three Access Language Paradigms

Richard Light (richard@light.demon.co.uk)
Wed, 19 Nov 1997 16:41:22 +0000

In message <1.5.4.32.19971119155058.00a6527c@pop.mindspring.com>,
Jonathan Robie <jwrobie@mindspring.com> writes
>
>In XLL, is there a way to combine conditions with boolean operators? Say I
>am using XL7, and I need to do a query for those billable items for a
>particular patient number AND for a particular physician. Can I do this with
>XLL? If there are boolean operators, is there a way to specify precedence?

No. An XLL expression supports a chain of locators, each of which
starts from the last place you got to in the target document's
structure. You can have a second chain, pointing to somewhere else, in
which case the XPointer is deemed to point to the span witihn the
document whose end-points are the two elements or characters you have
specified by your locators.

I've just checked over the original TEI Extended Pointer mechanism on
which XPointers are based, and there is nothing in that to support
boolean logic either.

Richard Light
SGML/XML and Museum Information Consultancy
richard@light.demon.co.uk