[tmcl-wg] Template and Expression layers: both needed for tmcl?

[Robert Barta]

On Sat, Mar 22, 2003 at 09:19:12PM +0900, Mary Nishikawa wrote:
> *Robert Barta
> 
> commenting on section 1.1.2.1:
> http://www.isotopicmaps.org/tmcl/requirements/
> 
> I do see the question whether there should be a
> 
>   TL (template layer), and a
>   EL (expression  layer)
> 
> independent whether the can be morphed into XML or not.
> 
> 
> *MN
> Comments Please!!! thanks 

I still like it :-)

Just to demonstrate the - probably - obvious thing, have a look
at the OSL template:

  <topic>
    <instanceOf>
      <internalTopicRef href="#TMTT_Standard"/>
    </instanceOf>

    <baseName min="1" max="Inf">
      <scope></scope>
    </baseName>
  </topic>

This TL could be translated into a expression ala:

forall $t [ * (TMTT_Standard) ]
   => exists $t [ bn : * ]

--

If we add the occurrence to it:

  <topic>
    <instanceOf>
      <internalTopicRef href="#TMTT_Standard"/>
    </instanceOf>

    <occurrence external="yes">
      <instanceOf>
        <internalTopicRef href="#TMOR_Specification"/>
      </instanceOf>
    </occurrence>

    <occurrence external="yes">
      <instanceOf>
        <internalTopicRef href="#TMOR_Homepage"/>
      </instanceOf>
    </occurrence>
  </topic>

then we would write

forall $x [ * (TMTT_Standard) ]
   forall $x [ oc ($t): * ]
      => exists $x [ oc ($t =~ TMOR_Specification) : * ]
         OR
         exists $x [ oc ($t =~ TMOR_Homepage) : * ]

\rho