[xquery-talk] Re: Best engine for learning?

Jason Hunter jhunter at servlets.com
Tue May 13 15:31:50 PDT 2003

Per Bothner wrote:

>  > 2) The engine must be rigorously faithful to the specs.  People
>  > shouldn't learn bad habits.
> Huh?  The most recent specs are about a week old.  

True.  I wouldn't expect conformance to the May drafts.  November 2002
would be nice.  I actually like any engine that conforms well to a
particular date, rather than being a mix with some-April, some-November,
and some-May for example.  It gets old trying everything three different
ways.  :-)

> Even those have
> plenty of inconsistencies and unclear issues.  Are there any
> implementations are are "regorously faithful to the specs"?  Even
> the Novembver '02 version?  

Good question.  I'd hope to point newbies at an engine that was as
faithful as possible, with the ideal being one where the developers say,
"It's not perfect, but we can't do anything to be more compliant til the
next draft rev clears some things up."

> One peeve:  On the x-query.com homepage, only Qexo is listed as a
> "partial implementation", with the misleading implication that the
> other implementations are complete.  Qexo is complete enough
> to do useful work with, as illustrated by the pages linked to
> from Qexo home page (http://www.gnu.org/software/qexo/).
> I admit there are big holes;  no schema support, very limited
> static typing (though the hooks are there), no sorting, no
> duplicate removal in path expressions, many functions are not
> yet implemented, builtin functions are in the wrong namespace.
> But it has FLWR expressions, functions, typeswitch, some typing
> support, element constructors (both kinds), namespace support
> (except for namespace nodes), an efficient XML parser and DOM
> representation, decent error handling, a Java interface, lots
> of functions, and can be used in various modes, including
> command-line and servlets.

<grin> I knew I was getting myself into hot water by expressing any
opinions about engines.  The list of items TBD on Qexo justifies its
"partial" status IMO.  Whether the others can or should be inferred to
be "complete" is debatable, but their "pending" lists seem significantly
shorter.  I don't mean to offend anyone, but I do want to provide a
little editorial guidance for visitors so they know what to expect.


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