src/mjacob/nltk/parse/tag/AbstractTagChartRule.py

   1 # This Python file uses the following encoding: utf-8
   2 '''
   3 Created on May 18, 2011
   4
   5
   6 @author: mjacob
   7 '''
   8 from itertools import product
   9 from nltk.parse.chart import AbstractChartRule
  10
  11 class AbstractTagChartRule(AbstractChartRule):
  12     def application_filter(self, chart, grammar):
  13         return {}
  14
  15     def applies_to(self, chart, grammar, edge):
  16         """
  17         i was going to do some sophisticated caching of this data, but
  18         now i'm pretty sure it's only called once for every edge/rule combo
  19         so that would be a complete waste
  20         """
  21         for key, value in list(self.application_filter(chart, grammar).items()):
  22             if not hasattr(edge, key):
  23                 raise ValueError("unexpected key %s" % (key))
  24             if getattr(edge, key)() != value:
  25                 return False
  26         return True
  27
  28     # Default: loop through the given number of edges, and call
  29     # self.apply() for each set of edges.
  30     def apply_everywhere_iter(self, chart, grammar):
  31         for edges in product(chart, repeat=self.NUM_EDGES):
  32             for new_edge in self.apply_iter(chart, grammar, *edges):
  33                 yield new_edge
  34
  35     def apply(self, *args):
  36         super(AbstractTagChartRule, self).apply(*args)