nominatim/tokenizer/icu_token_analysis.py

   1 # SPDX-License-Identifier: GPL-2.0-only
   2 #
   3 # This file is part of Nominatim. (https://nominatim.org)
   4 #
   5 # Copyright (C) 2022 by the Nominatim developer community.
   6 # For a full list of authors see the git log.
   7 """
   8 Container class collecting all components required to transform an OSM name
   9 into a Nominatim token.
  10 """
  11
  12 from icu import Transliterator
  13
  14 class ICUTokenAnalysis:
  15     """ Container class collecting the transliterators and token analysis
  16         modules for a single NameAnalyser instance.
  17     """
  18
  19     def __init__(self, norm_rules, trans_rules, analysis_rules):
  20         self.normalizer = Transliterator.createFromRules("icu_normalization",
  21                                                          norm_rules)
  22         trans_rules += ";[:Space:]+ > ' '"
  23         self.to_ascii = Transliterator.createFromRules("icu_to_ascii",
  24                                                        trans_rules)
  25         self.search = Transliterator.createFromRules("icu_search",
  26                                                      norm_rules + trans_rules)
  27
  28         self.analysis = {name: arules.create(self.normalizer, self.to_ascii, arules.config)
  29                          for name, arules in analysis_rules.items()}
  30
  31
  32     def get_analyzer(self, name):
  33         """ Return the given named analyzer. If no analyzer with that
  34             name exists, return the default analyzer.
  35         """
  36         return self.analysis.get(name) or self.analysis[None]