[sc34wg3] Problem with wildcards

Lars Marius Garshol larsga at garshol.priv.no
Sat Feb 28 05:11:00 EST 2009

While waiting for the baby to fall asleep last night I thought of a  
problem with wildcards. Imagine that we have geo.ctm, which contains  
all kinds of nice geographical stuff, including:

def capital($country, $name)
   ?capital isa city;
     - $name .
   is-located-in(location: $country, located: ?capital)
   capital-of(region: $country, capital: ?capital)

Looks reasonable, right?

Then we write in norway.ctm:
   %include <geo.ctm>
   norway isa geo:country;

And later sweden.ctm:
   %include <geo.ctm>
   sweden isa geo:country;

If we ever decide to merge sweden.ctm and norway.ctm Oslo and  
Stockholm wind up merging, because they both have the same item  

One possible fix might be to change the rules for %include so that  
only the item identifiers from the including master file are  
preserved, and the ones from the included file are lost.

Or maybe we have to give up the goal of predictable item identifiers  
for wildcards, although that would suck royally, as a lot of the tests  
in the suite rely on this.

--Lars M.

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