nltk/nltk — Issue #127: Trees do not display unified features correctly
Author: alexrudnick
Created: 2012-01-17 06:26:41+00:00
State: open

Reported by Rajesh on the nltk-users list:

The final trees returned by the parser do not display full resolution of unified features. One can see that full reunification actually takes place as in the cases when it does not, one gets failure of unification as expected. Is there a way to force the features in the final tree to be the resolved features?

Here's an example of the problem [I haven't installed the new version
yet; this is what I am getting with the older version]:

Jody disappeared today

(CProot[]
(S[+FIN]
(NP[AGR=[NUM='sg', PER=3], -WH]
(NAME[AGR=[NUM='sg', PER=3]] Jody))
(VP[AGR=?a, +FIN]
(VP[AGR=?a, +FIN]
(V[-AUX, -COP, +FIN, SUBCAT='intrans'] disappeared))
(AdvP[-WH] today))))

I have a rule that unifies the AGR feature of the NP and VP and so
AGR=?a on the VP should get resolved to [NUM='sg', PER=3]. The feature
unifier is behaving correctly here as one can see by putting in a V
with the wrong features. But the display mechanism does not show the
resolution.

Migrated from http://code.google.com/p/nltk/issues/detail?id=607