Component Model Aspect-oriented Components Brainstorming

Example

component declaration:

 <template name="x-base">
     <template name="top">
         <content select="X"></content>
     </template>
     <template name="center">
         <content select="Y"></content>
     </template>
     <template name="bottom">
         <content select="Z"></content>
     </template>
     <template> 
         <use name="top"></use>
         <use name="center"></use>
         <use name="bottom"></use>
         <content select="W"></content>        
     </template>
   </template>

derived component overriding main template. Pattern derived components will use most often.

 <template name="x-derived1" base="x-base">
     <template>
         <content select="Z"></content>        
         <use name="top"></use>
         <use name="center"></use>
         <use name="bottom"></use>
     </template>
 </template>

derived component overriding a part template. All <use> elements referring to "top" in the finalized component will now render below structure instead. Pattern decorators will use most often

 <template name="x-derived2" base="x-base">
     <template name="top">
         <content select="X"></content>
         <content select="Z"></content>        
     </template>
 </template>

combination: derived component overriding main template and a part template, and adding a new template, all at once. Pattern derived components will use often.

 <template name="x-derived1" base="x-base">
     <template name="bottom">
         <hr>
         <content select="Z"></content>
     </template>
     <template name="left">
         <content select="Y"></content>
     </template>
     <template>
         <use name="top"></use>
         <use name="bottom"></use>
     </template>
 </template>

Issues

• Splitting scripting among parts - how to "re-route" scripting to overriding parts? probably not possible -> rely on heavy messaging instead?
• Overriding parts again requires a certain knowledge of a components internals - at least which parts exist and what they do (then again, this is also the point)
• How to best apply & remove "decorators"?
• It's not possible to extend a template or part (adding or wrapping the base part, but also rendering it) - it's either leave the original or replace it completely. The ability to extend seems desirable in some cases, but would then re-raise the XBL inheritance questions. How to best reconcile this? (or ignore it?)
• In some sense all this creates a mother-of-all-flattened-trees
• Can this work if some parts are being isolated?