+# SPDX-License-Identifier: GPL-2.0-only
+#
+# This file is part of Nominatim. (https://nominatim.org)
+#
+# Copyright (C) 2022 by the Nominatim developer community.
+# For a full list of authors see the git log.
"""
Generic processor for names that creates abbreviation variants.
"""
-from collections import defaultdict
import itertools
-from icu import Transliterator
import datrie
+from nominatim.errors import UsageError
+from nominatim.tokenizer.token_analysis.config_variants import get_variant_config
+from nominatim.tokenizer.token_analysis.generic_mutation import MutationVariantGenerator
+
+### Configuration section
+
+def configure(rules, normalization_rules):
+ """ Extract and preprocess the configuration for this module.
+ """
+ config = {}
+
+ config['replacements'], config['chars'] = get_variant_config(rules.get('variants'),
+ normalization_rules)
+ config['variant_only'] = rules.get('mode', '') == 'variant-only'
+
+ # parse mutation rules
+ config['mutations'] = []
+ for rule in rules.get('mutations', []):
+ if 'pattern' not in rule:
+ raise UsageError("Missing field 'pattern' in mutation configuration.")
+ if not isinstance(rule['pattern'], str):
+ raise UsageError("Field 'pattern' in mutation configuration "
+ "must be a simple text field.")
+ if 'replacements' not in rule:
+ raise UsageError("Missing field 'replacements' in mutation configuration.")
+ if not isinstance(rule['replacements'], list):
+ raise UsageError("Field 'replacements' in mutation configuration "
+ "must be a list of texts.")
+
+ config['mutations'].append((rule['pattern'], rule['replacements']))
+
+ return config
+
+
### Analysis section
-def create(norm_rules, trans_rules, config):
+def create(normalizer, transliterator, config):
""" Create a new token analysis instance for this module.
"""
- return GenericTokenAnalysis(norm_rules, trans_rules, config['variants'])
+ return GenericTokenAnalysis(normalizer, transliterator, config)
class GenericTokenAnalysis:
and provides the functions to apply the transformations.
"""
- def __init__(self, norm_rules, trans_rules, replacements):
- self.normalizer = Transliterator.createFromRules("icu_normalization",
- norm_rules)
- self.to_ascii = Transliterator.createFromRules("icu_to_ascii",
- trans_rules +
- ";[:Space:]+ > ' '")
- self.search = Transliterator.createFromRules("icu_search",
- norm_rules + trans_rules)
-
- # Intermediate reorder by source. Also compute required character set.
- immediate = defaultdict(list)
- chars = set()
- for variant in replacements:
- if variant.source[-1] == ' ' and variant.replacement[-1] == ' ':
- replstr = variant.replacement[:-1]
- else:
- replstr = variant.replacement
- immediate[variant.source].append(replstr)
- chars.update(variant.source)
- # Then copy to datrie
- self.replacements = datrie.Trie(''.join(chars))
- for src, repllist in immediate.items():
- self.replacements[src] = repllist
-
-
- def get_normalized(self, name):
- """ Normalize the given name, i.e. remove all elements not relevant
- for search.
+ def __init__(self, norm, to_ascii, config):
+ self.norm = norm
+ self.to_ascii = to_ascii
+ self.variant_only = config['variant_only']
+
+ # Set up datrie
+ if config['replacements']:
+ self.replacements = datrie.Trie(config['chars'])
+ for src, repllist in config['replacements']:
+ self.replacements[src] = repllist
+ else:
+ self.replacements = None
+
+ # set up mutation rules
+ self.mutations = [MutationVariantGenerator(*cfg) for cfg in config['mutations']]
+
+
+ def normalize(self, name):
+ """ Return the normalized form of the name. This is the standard form
+ from which possible variants for the name can be derived.
"""
- return self.normalizer.transliterate(name).strip()
+ return self.norm.transliterate(name).strip()
+
def get_variants_ascii(self, norm_name):
""" Compute the spelling variants for the given normalized name
and transliterate the result.
"""
- baseform = '^ ' + norm_name + ' ^'
- partials = ['']
+ variants = self._generate_word_variants(norm_name)
- startpos = 0
- pos = 0
- force_space = False
- while pos < len(baseform):
- full, repl = self.replacements.longest_prefix_item(baseform[pos:],
- (None, None))
- if full is not None:
- done = baseform[startpos:pos]
- partials = [v + done + r
- for v, r in itertools.product(partials, repl)
- if not force_space or r.startswith(' ')]
- if len(partials) > 128:
- # If too many variants are produced, they are unlikely
- # to be helpful. Only use the original term.
- startpos = 0
- break
- startpos = pos + len(full)
- if full[-1] == ' ':
- startpos -= 1
- force_space = True
- pos = startpos
- else:
- pos += 1
- force_space = False
+ for mutation in self.mutations:
+ variants = mutation.generate(variants)
- # No variants detected? Fast return.
- if startpos == 0:
- trans_name = self.to_ascii.transliterate(norm_name).strip()
- return [trans_name] if trans_name else []
+ return [name for name in self._transliterate_unique_list(norm_name, variants) if name]
- return self._compute_result_set(partials, baseform[startpos:])
+ def _transliterate_unique_list(self, norm_name, iterable):
+ seen = set()
+ if self.variant_only:
+ seen.add(norm_name)
- def _compute_result_set(self, partials, prefix):
- results = set()
+ for variant in map(str.strip, iterable):
+ if variant not in seen:
+ seen.add(variant)
+ yield self.to_ascii.transliterate(variant).strip()
- for variant in partials:
- vname = variant + prefix
- trans_name = self.to_ascii.transliterate(vname[1:-1]).strip()
- if trans_name:
- results.add(trans_name)
- return list(results)
+ def _generate_word_variants(self, norm_name):
+ baseform = '^ ' + norm_name + ' ^'
+ baselen = len(baseform)
+ partials = ['']
+ startpos = 0
+ if self.replacements is not None:
+ pos = 0
+ force_space = False
+ while pos < baselen:
+ full, repl = self.replacements.longest_prefix_item(baseform[pos:],
+ (None, None))
+ if full is not None:
+ done = baseform[startpos:pos]
+ partials = [v + done + r
+ for v, r in itertools.product(partials, repl)
+ if not force_space or r.startswith(' ')]
+ if len(partials) > 128:
+ # If too many variants are produced, they are unlikely
+ # to be helpful. Only use the original term.
+ startpos = 0
+ break
+ startpos = pos + len(full)
+ if full[-1] == ' ':
+ startpos -= 1
+ force_space = True
+ pos = startpos
+ else:
+ pos += 1
+ force_space = False
- def get_search_normalized(self, name):
- """ Return the normalized version of the name (including transliteration)
- to be applied at search time.
- """
- return self.search.transliterate(' ' + name + ' ').strip()
+ # No variants detected? Fast return.
+ if startpos == 0:
+ return (norm_name, )
+
+ if startpos < baselen:
+ return (part[1:] + baseform[startpos:-1] for part in partials)
+
+ return (part[1:-1] for part in partials)
projects / nominatim.git / blobdiff