public class TreeCollinizer
Does detransformations to a parsed sentence to map it back to the
standard treebank form for output or evaluation.
This version has Penn-Treebank-English-specific details, but can probably
be used without harm on other treebanks.
Returns labels to their basic category, removes punctuation (should be with
respect to a gold tree, but currently isn't), deletes the boundary symbol,
changes PRT labels to ADVP.
Does whatever one needs to do to a particular tree.
This routine is passed a whole Tree, and could itself
work recursively, but the canonical usage is to invoke this method
via the Tree.transform() method, which will apply the
transformer in a bottom-up manner to each local Tree,
and hence the implementation of TreeTransformer should
merely examine and change a local (one-level) Tree.