Yeah - I guess I read that line and didn't think much about it until now.
So, when other parameters in the same call aren't the empty sequence, could
it be considered a bug that the entire function isn't called?
Steve
On Fri, Apr 2, 2010 at 3:25 PM, Danny Sokolsky <danny.sokol...@marklogic.com
> wrote:
> What is happening is that, as a result of function mapping, when you pass
> in the empty sequence the function is being called 0 times.
>
> Here is what the documentation says to try and explain this (from the
> "MarkLogic Server Enhanced XQuery Language" chapter of the XQuery Reference
> Guide):
>
> One consequence of function mapping, which can be surprising the first time
> you see it, is that if the value passed for a parameter is the empty
> sequence, it could result in the function being called 0 times (that is, in
> the function never runs and results in the empty sequence. For example, if
> you entered the empty sequence as the parameter to the above function call,
> it returns empty, as follows:
>
> xquery version "1.0-ml";
>
> declare function local:print-word ($word as xs:string) { $word };
>
> local:print-word( () )
> (:
> evaluates the print-word function zero times, resulting
> in the empty sequence
> :)
>
> The local:print-word function is never called in this case, because it is
> iterating over the empty sequence, which causes zero invocations of the
> function. If your function calls are fed by code that can return the empty
> sequence (an XPath expression, for example), then you might see this
> behavior.
>
> -Danny
>
> From: general-boun...@developer.marklogic.com [mailto:
> general-boun...@developer.marklogic.com] On Behalf Of spig
> Sent: Friday, April 02, 2010 2:19 PM
> To: General Mark Logic Developer Discussion
> Subject: Re: [MarkLogic Dev General] Unexpected behavior
>
> Yes, with xdmp:mapping set to "false" it does throw an expected coercion
> error.
>
> So, how come?
>
> I was under the impression that xdmp:mapping applies the function's logic
> to each parameter. Does xdmp:mapping also not call functions under certain
> circumstances? Is there someone who can help explain this functionality or a
> document I can read?
>
> Steve
>
> So, can someone explain, or point me to a document where xdmp:mapping is
> explained? I've read the xdmp:mapping section in the MarkLogic
> On Fri, Apr 2, 2010 at 3:05 PM, Micah Dubinko <micah.dubi...@marklogic.com>
> wrote:
> Try turning off function mapping with this declration at the top (after any
> module imports)
>
> declare option xdmp:mapping "false";
>
> Does that at least allow the function to get called (or cause a coercion
> error involving ())?
>
> -m
>
> On Apr 2, 2010, at 2:01 PM, spig wrote:
>
> > The point is that the function is never called (it is throwing fn:error
> just to prove that it's not called, errors or not). Also, there is no
> warning that the function is not being called, or that there is an error in
> the parameter. Anyone know why this is? Try running the code and you'll see
> what I mean. It's almost like there is a hidden try/catch around my code -
> no errors raised and doesn't show that nothing was called.
> >
> > Steve
> >
> > On Fri, Apr 2, 2010 at 2:55 PM, Ruth Stryker <ruth.stry...@marklogic.com>
> wrote:
> > Hi spig,
> >
> >
> > Not sure about fn:error(). Maybe approach with try get instead.?
> >
> >
> > try {
> > 1 div 0
> > }
> > catch ($e) {
> > $e
> > }
> >
> > Or just use an if then else for checking if your field exists.?
> >
> >
> > if(xdmp:get-request-field("q"))
> >
> > then local:search-results()
> >
> > else .
> >
> >
> >
> >
> > From: general-boun...@developer.marklogic.com [mailto:
> general-boun...@developer.marklogic.com] On Behalf Of spig
> > Sent: Friday, April 02, 2010 1:43 PM
> > To: general@developer.marklogic.com
> > Subject: [MarkLogic Dev General] Unexpected behavior
> >
> >
> > If I run the following code, my function is never called and no errors
> are raised. Any ideas?
> >
> >
> > xquery version "1.0-ml";
> >
> > declare function local:test($param1 as xs:string, $param2 as xs:string,
> $param3 as xs:string) {
> > fn:error()
> > };
> >
> > let $var := xdmp:get-request-field("non-existent-param")
> >
> > let $blah := local:test("", "", $var)
> >
> > return "Function Call Successful"
> >
> >
> >
> > Thanks,
> > Steve Spigarelli
> >
> >
> > _______________________________________________
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> >
> >
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