Re: [xsl] simplifying the XSL for an intersection

[Joerg Heinicke <joerg.heinicke@xxxxxx>]

Hello Leona,

isn't it possible that your requirement gets out of hand? For example I 
add an Item like the following:

<Item iID="1">
    <RoleLink iRoleID="X"/>
    <RoleLink iRoleID="A"/>
</Item>

and a simple Role like the following:

<Role roleID="A">
    <PlayerLink player="1"/>
    <PlayerLink player="3"/>
</Role>

A won't be caught in the first run, but maybe it has to, because it's in 
the same Item as X. It seems that a recursive approach is needed, isn't it?

Without recursion and not really simpler, but I think more readable and 
easier to understand is the following rewriting:

<xsl:variable name="player" select="53"/>

You can pull the root element <Matrix/> into the variable declaration of 
$matrix. So you avoid to type it always in the expressions below:
<xsl:variable name="matrix" select="document('matrix.xml')/Matrix"/>

<xsl:variable name="playerroles" 
select="$matrix/Role[PlayerLink/@player=$player]"/>

Your expression was:
<xsl:variable name="matrixroles"
select="$matrix/Role[@roleID = $matrix/Item/RoleLink/@iRoleID
[../../RoleLink/@iRoleID = $playerroles/@roleID]]"/>

rewritten:
<xsl:variable name="matrixroles"
select="$matrix/Role[@roleID = $matrix/Item
[RoleLink/@iRoleID = $playerroles/@roleID]/RoleLink/@iRoleID]"/>

or adding a new variable for further better readability:

<xsl:variable name="items" select="$matrix/Item[RoleLink/@iRoleID = 
$playerroles/@roleID]"/>
<xsl:variable name="matrixroles" 
select="$matrix/Role[@roleID=$items/RoleLink/@iRoleID]"/>

Does this help a bit? And what about my first comment?

Regards,

Joerg

leona s wrote:
> Hi All,
>
> I am trying to get a set of nodes that is really an intersection
> and would appreciate some ideas for a solution.
>
> What I need is the set of Matrix/Role nodes,
>   that contains all of Roles for Items
>   where $player is in at least one of the Roles for that Item.
>
> For example, if I have a variable $player = '53', I
> should get the set of Roles where roleID = {W,X,Y}, because
> 53 is in W and Y, and although 53 is not in X, that Role
> is in at least one Item that also has roles W and Y. Also,
> 53 is in Role Z, but that Role does not belong to any Item so it is not
> included.
>
> I have a solution that works, but I was wondering if there is a simpler
> way to express this.
>
> <xsl:variable name="player" select="53"/>
> <xsl:variable name="matrix" select="document('matrix.xml')"/>
> <xsl:variable name="playerroles"
> select="$matrix/Matrix/Role[PlayerLink/@player=$player]"/>
> <xsl:variable name="matrixroles"
> select="$matrix/Matrix/Role[@roleID=$matrix/Matrix/Item/RoleLink/@iRoleID[..
> /../RoleLink/@iRoleID=$playerroles/@roleID]]"/>
>
> <Matrix>
>   <Role roleID="W">
>     <PlayerLink player="1"/>
>     <PlayerLink player="3"/>
>     <PlayerLink player="6"/>
>     <PlayerLink player="53"/>
>   </Role>
>   <Role roleID="X">
>     <PlayerLink player="1"/>
>     <PlayerLink player="3"/>
>   </Role>
>   <Role roleID="Y">
>     <PlayerLink player="1"/>
>     <PlayerLink player="3"/>
>     <PlayerLink player="51"/>
>     <PlayerLink player="53"/>
>   </Role>
>   <Role roleID="Z">
>     <PlayerLink player="3"/>
>     <PlayerLink player="53"/>
>   </Role>
>
>   <Item iID="123">
>     <RoleLink iRoleID="W"/>
>     <RoleLink iRoleID="X"/>
>     <RoleLink iRoleID="Y"/>
>   </Item>
>
>   <Item iID="456">
>     <RoleLink iRoleID="X"/>
>     <RoleLink iRoleID="Y"/>
>   </Item>
>
>   <Item iID="789">
>     <RoleLink kgRoleID="Y"/>
>   </Item>
> </Matrix>
>
> Thanks very much,
> Leona Slepetis
> lrs@xxxxxxxxxxxx


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