anchor.diff:    <container id="lastname"/>
   </template>
   
  +Finally, it is not clear to me whether the following is correct or not, but we could give more controls to templates throw some calculation, although I think EVERY calculation should be in the controller, so...
  +
  +We could have some expressions that expand to dataflow cells:
  +
  +<template class="person-viewer">
  +  <container id="name"/>
  +  <container id="lastname"/>
  +  <div class="age">
  +    <formula f="(+1 (age comp))"/>
  +  </div>
  +</template>
  +
  +(+1 (age comp)) should expand to something like:
  +
  +(make-formula :formula (lambda ()
  +			 (+1 (age comp)))) and compiled in an environment where comp makes sense
  +
  +
  +
  +
   |#
positive.code: </template>
  
  <template class="employee-viewer">
     <sub-template/>
     <container id="company"/>
  </template>
  
  
  Last, but not least, we should make the template system extensible. On the one hand, it should be possible to implement
  new template-combinations. On the other hand, the template system should be extensible by means of options too. So, for example, we should be able to implement layered templates extending the options engine:
  
  <template class="person-viewer"
  
negative.code: <template class="<component-class>"
            combination="<template-combination>">
     ...
     <next-template/>
  </template>
  
  Examples:
  
  We may want to have :above (equivalent to :before), :below (equivalent to :after) and :around. Besides, we can embed other templates (in the case of subclassing or :around method combinations, for example) using the special XML element <next-template/>
  
  <template class="object-editor"
            combination="above">
  