Homework 03

Download the data. The zip file contains a part of PDT annotated up to the tectogrammatical layer (t-layer), namely directory train-1 with t-files (tectogrammatical layer), a-files (analytical layer), m-files (morphological layer) and w-files (word layer).

Write a btred script that searches for a-nodes (nodes on the analytical layer) that are not referred to from the tectogrammatical layer (i.e. from any t-node).
Using the system of hooks in the btred script, compute and print a (sorted) distribution list of analytical functions (attribute afun) of these a-nodes.
As a result of the homework, submit both the script and the resulting distribution.

Before delivering the homework, make sure that the distribution starts with these lines:

  4113 AuxK
  3733 AuxX

and ends with these lines:

    11 Apos
     1 Adv

(The leading spaces do not matter.)

Notes

The analytical tree (its root node) is referred to from the root of the tectogrammatical tree in the attribute atree.rf.
$root->attr('atree.rf') - gets an id of the root of the analytical tree corresponding to the tectogrammatical tree given by $root
PML_T::GetANodeByID($a_node_id) - gets a node at the analytical layer with a given id
PML_T::GetANodes($t_node) - gets analytical counterparts of the given tectogrammatical node (both lexical and auxiliary)
To compute the distribution in the btred script, you need to redefine function exit_hook. Its description in the documentation is not entirely clear, it should also mention that - if used in btred - it is executed once after all input files are processed.