[xquery-talk] Re: Optimizations

Fri Oct 3 16:23:45 PDT 2008

Hi again,

In the same spirit, this is not at all optimized.
Maybe I need Saxon SA ?

declare variable $level as xs:integer := 3 ;

declare function local:debug($l as xs:integer,$what){
  if($l >=4) then
    <debug>{$what}</debug>
  else ()
};

let $dosmthg := <oki>test trace</oki>

return
(local:debug($level,$dosmthg),$dosmthg)

Rémi

On Fri, Oct 3, 2008 at 3:17 PM, Rémi Dewitte <remi at gide.net> wrote:

> Hi,
>
> I have made a little experiment after reading Michael (Kay) blog posts
> about optimizations and recent James Fuller article.
>
> I have a question quite specific to saxon still interesting in general.
>
> Why in the following example even the function call is not skipped ?
>
>
> XQuery is ::
>
> declare variable $level := 3;
>
> declare function local:debug($what){
>   if($level >=4) then
>     <debug>{$what}</debug>
>   else ()
> };
>
> let $dosmthg := <oki>test trace</oki>
>
> return
> (local:debug($dosmthg),$dosmthg)
>
> When I run saxon with -explain we get
>
> <query>
>   <globalVariables>
>     <declareVariable name="level">
>       <literal value="3" type="xs:integer"/>
>     </declareVariable>
>   </globalVariables>
>   <declareFunction name="local:debug" tailRecursive="false">
>     <literal value="()"/>
>   </declareFunction>
>   <body>
>     <let variable="dosmthg" as="element(oki, {
> http://www.w3.org/2001/XMLSchema}untyped<http://www.w3.org/2001/XMLSchema%7Duntyped>
> )">
>       <be>
>         <directElement name="oki" validation="skip">
>           <valueOf>
>             <literal value="test trace" type="xs:string"/>
>           </valueOf>
>         </directElement>
>       </be>
>       <return>
>         <sequence>
>           <functionCall name="local:debug" tailCall="false">
>             <variableReference name="dosmthg"/>
>           </functionCall>
>           <variableReference name="dosmthg"/>
>         </sequence>
>       </return>
>     </let>
>   </body>
> </query>
>
> Cheers,
> Rémi
>
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