Creating supertype for PNG

#1

In some analyses in my library, I need to have a PNG feature introduced at a new point, namely on the HEAD.POSS feature that I’ve defined in matrix.tdl in my branch:

head := head-min &
[ ...
POSS poss ].

poss := *top*.
possessive := poss.
nonpossessive := poss.
possessor := possessive.
possessum := possessive.

Right now, PNG is defined on ref-ind:

ref-ind := index & event-or-ref-index &
[ PNG png ].

So I can’t just add it to POSS like this:

poss :+ [ PNG png ].

Without getting a ‘feature is introduced at multiple types’ error from the LKB. I tried creating a supertype along these lines that both ref-ind and poss could inherit from:

png-item := avm & [ PNG png ].

But that made the regression test crash – as in not produce any results whatsoever. I think there’s some way to create a supertype for both ref-ind and poss, but I’m having a hard time figuring out what it would look like.

#2

You can’t add the feature PNG to any type that doesn’t inherit from ref-ind (or that ref-ind doesn’t inherit from).

However, you don’t want to add the feature anyway. You want to add a different feature with the same range of possible values as the feature PNG. That is, the type is what you’re reusing, not the feature.

So:

poss :+ [ POSS-AGR png ].