[Zope3-dev] RFC: zcml:condition

[Jim Fulton]

Roger Ineichen wrote:
> Hi Jim
> 
>>-----Original Message-----
>>From: zope3-dev-bounces+dev=projekt01.ch at zope.org 
>>[mailto:zope3-dev-bounces+dev=projekt01.ch at zope.org] On 
>>Behalf Of Jim Fulton
>>Sent: Thursday, February 17, 2005 10:42 PM
>>To: zope3-dev at zope.org
>>Subject: [Zope3-dev] RFC: zcml:condition
>>
>>
>>We've identified a real need for conditional ZCML
>>processing.
>>
>>Consider an optional feature, like onlinehelp or zsync.
>>These system define directives or components that individual
>>packages will want to provide if these systems are available.
>>
>>For example, a package might want to register on-line-help
>>documents if the on-line help system is available:
>>
>><configure
>>     xmlns="http://namespaces.zope.org/zope"
>>     xmlns:help="http://namespaces.zope.org/help"
>>     zcml:condition="have onlinehelp"
>>     >
>>
>>   <help:register
>>       id="zope.app.authentication"
>>       parent="dev"
>>       title="Authentication"
>>       doc_path="README.txt"
>>       class="zope.app.onlinehelp.onlinehelptopic.RESTOnlineHelpTopic"
>>       />
>>
>>   <help:register
>>       id="principalfolder"
>>       parent="dev/zope.app.authentication"
>>       title="Principal Folder"
>>       doc_path="principalfolder.txt"
>>       class="zope.app.onlinehelp.onlinehelptopic.RESTOnlineHelpTopic"
>>       />
>>
>>   <help:register
>>       id="groupfolder"
>>       parent="dev/zope.app.authentication"
>>       title="Group Folder"
>>       doc_path="groupfolder.txt"
>>       class="zope.app.onlinehelp.onlinehelptopic.RESTOnlineHelpTopic"
>>       />
>>
>></configure>
> 
> 
> Can we use this condition like a sub configure directive:
> 
> <configure
>      xmlns="http://namespaces.zope.org/zope">
> 
>   <browser:page
>      name="foo"
>      template="foo.pt"
>      ...
>      />
> 
>   <configure
>      xmlns:help="http://namespaces.zope.org/help"
>      zcml:condition="have onlinehelp"
>      >
> 
>    <help:register
>        id="zope.app.authentication"
>        parent="dev"
>        title="Authentication"
>        doc_path="README.txt"
>        class="zope.app.onlinehelp.onlinehelptopic.RESTOnlineHelpTopic"
>        />
> 
>    <help:register
>        id="principalfolder"
>        parent="dev/zope.app.authentication"
>        title="Principal Folder"
>        doc_path="principalfolder.txt"
>        class="zope.app.onlinehelp.onlinehelptopic.RESTOnlineHelpTopic"
>        />
>   </configure>
> 
> </configure>

Yup.

> Or what's the scope of the zcml:condition.

The condition attribute applies to the elements it's on (and all
subelements, of course).  It can go on any element in zcml.

The condigure directive is a pure grouping directive. It can be
used as many times as you want.  It's roughly the zcml equivalent
of div.

Jim

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