[xsl] Help with recursion (was: my brain is hurting)

[Chris Picton <chrisp@xxxxxxxxxxxxx>]

Hi all

Sorry about the subject line - my brain was more off than hurting, and 
looking at the instance I gave, I wonder why I wrote that at all.  I had 
only just joined the list, and so didn't see David's mail about 
meaningful subject lines (which I should have used anyway).  Sorry

Let my try clear up my own confusion (as I was writing from home where I 
didn't have my instance in front of me)

I have two (or more) separate subtrees in the instance.
The first, <users>, defines users and group and the relationship between 
them, and looks like:

 <users>
   <user name="chris" parent="othergroup">
     ...
   </user>
   <user name="phil" parent="othergroup">
     ...
   </user>
   <group name="default" parent="">
     ...
   </group>
   <group name="othergroup" parent="default">
     ...
   </group>
 </users>

The ... are to refer to extra nodes regarding the user not important 
here (such as full name, password, etc)

Then there is the <settings> subtree (there could be more than on such 
subtree, with settings for a different aspect of the user).  I cannot 
merge the settings subtrees with the users subtrees, though (ie, I 
cannot have the settings per user under the <user> node the the <users> 
subtree).  Design decision out of my hands.

the <settings> subtree looks like (fixed from first mail, and have 
renamed some nodes for legibility)

 <modulesettings>
   <user name="chris">
     <module useparent="1" >
         ...empty...
     </module>
   </user>
   <user name="phil">
     <module useparent="0" >
         ...module settings...
     </module>
   </user>
   <group name="default">
     <module useparent="0" >
         ...module settings...
     </module>
   </group>
   <group name="othergroup">
     <module useparent="1" >
         ...empty...
     </module>
   </group>
 </settings>

the 'useparent' attribute specifies if that user or group should inherit 
its settings from its parent (1), or if it should specify its own (0).  
I am trying to get a list of users per group who should use the settings 
defined by that group.

I iterate over each group name, and run the transform with <param 
name='group'/>, passing in each group name in turn.

In the above case, user 'phil' is not inheriting setting from the 
parent, and as such wont appear in the list for any group.
User 'chris' is inheriting from group 'othergroup', which is in turn 
inheriting from group 'default'.  So, the user list for group 'default' 
should contain the user 'chris'.
The user list list for group 'othergroup' should be empty, as it has no 
settings of its own.

Hope that makes more sense!

I know I should be using recursion here, but I can't get my mind around 
the xsl way of doing things.


Thanks

Chris




Geert Josten wrote:

> Hi Chris,
>
> Could you be more precise? I'm confused about the way you are using 
> <usegroup> (which doesn't look like a valid element to me? And why 
> should parameter value 'default' result only in 'chris'?
>
> Cheers,
> Geert
>
> Chris Picton wrote:
>
> > Hi all
> >
> > I have the following xml structure.  To paraphrase quickly, I have users
> > and groups, each user or group has a parent group defined - except for
> > group 'default', which is always top of the tree.  I have settings for
> > each user and group.  Each settings node can be specified as 'use
> > settings from parent group', or 'specify my own settings'.
> >
> > <root>
> >   <settings>
> >     <user name="chris">
> >       <usegroup="1" />
> >     </user>
> >     <user name="phil">
> >       <usegroup="0" />
> >       ...
> >     </user>
> >     <group name="default">
> >       <usegroup="0" />
> >       ...
> >     </group>
> >     <group name="othergroup">
> >       <usegroup="1" />
> >     </group>
> >
> >   </settings>
> >   <users>
> >     <user name="chris" parent="othergroup">
> >       ...
> >     </user>
> >     <user name="phil" parent="othergroup">
> >       ...
> >     </user>
> >     <group name="default" parent="">
> >       ...
> >     </group>
> >     <group name="othergroup" parent="default">
> >       ...
> >     </group>
> >   </users>
> > </root>
> >
> >
> >
> > I am trying to write a transform which, when given a group name as a
> > parameter, will output a list of usernames which will use that group's
> > settings.
> >
> > Example, if parameter 'group' == default,
> > it will output "chris" in the above example
> >
> > However, my xsl skills are nowhere near good enough for this.
> >
> > Does anyone have ideas for me?
> >
> > Regards
> >
> > Chris