Mapping in real life

OK. So today's epiphany is as follows: Given a unit "invoice" which I have already specified (i.e. filled in), I can map that onto a "document" unit that might look like this:

document
  text title "Invoice #3"
  text customer
     Customer name
     Street 9
     D-whatever Germany
  text identifying
     Job # whatever
  table
     header
        text "Description"
        text "Units"
        text "Unit price"
        text "Price"
     row
        text "Translation DE-EN"
        text "4802 wds"
        text "See PO"
        text "438.00 €"
  text (align=right) "Total: 438.00 €"
  text bottom_boilerplate

This maps back and forth to the invoice, which is the abstract view of the same thing. And this can be specified even further with layout information, either in the abstract document or a different, more specific template, and then that structure can be mapped onto a Word document or PDF. (Or both.)

The point being that this map is then itself a live object that can be stored and represented, and that is semantic programming. This part is a lot like XSLT, because XSLT is all about mapping and transforming tree structures. But it's unlike XSLT because (1) it doesn't presume that the mapping is a one-way, one-time transformation, and (2) the organization of the maps and semantic units is organized in a lexical database somehow. That lexical database is itself the program. In some way.

I hope this cleared all that up.