[Xpath-ng] List constructor syntax

[Jeni Tennison]

Hi David,

>   Also, if we adopt the XPath 2.0 convention of using an empty list to
>   mean an unknown or invalid value,
>
> I'm fairly sure that's a bad convention, one that the xpath2 drafts
> seem to have been moving away from as far as possible.
>
> Initially they tried to use () as an "unknown" value and give
> logical operators three valued logic sematics using true() false()
> and () but using () as an exceptional value doesn't fit well with
> the fact that it's a perfectly normal and expected return value for
> any path expression, what used to be called an empty node set... So
> later xpath2 drafts seem to be backing off the 3 valued logic idea.

Yeah, all true.

Cheers,

Jeni

---
Jeni Tennison
http://www.jenitennison.com/