forked from hans/Nominatim
139 lines
4.8 KiB
Python
139 lines
4.8 KiB
Python
# 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.
|
|
"""
|
|
import itertools
|
|
|
|
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(transliterator, config):
|
|
""" Create a new token analysis instance for this module.
|
|
"""
|
|
return GenericTokenAnalysis(transliterator, config)
|
|
|
|
|
|
class GenericTokenAnalysis:
|
|
""" Collects the different transformation rules for normalisation of names
|
|
and provides the functions to apply the transformations.
|
|
"""
|
|
|
|
def __init__(self, to_ascii, config):
|
|
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 get_variants_ascii(self, norm_name):
|
|
""" Compute the spelling variants for the given normalized name
|
|
and transliterate the result.
|
|
"""
|
|
variants = self._generate_word_variants(norm_name)
|
|
|
|
for mutation in self.mutations:
|
|
variants = mutation.generate(variants)
|
|
|
|
return [name for name in self._transliterate_unique_list(norm_name, variants) if name]
|
|
|
|
|
|
def _transliterate_unique_list(self, norm_name, iterable):
|
|
seen = set()
|
|
if self.variant_only:
|
|
seen.add(norm_name)
|
|
|
|
for variant in map(str.strip, iterable):
|
|
if variant not in seen:
|
|
seen.add(variant)
|
|
yield self.to_ascii.transliterate(variant).strip()
|
|
|
|
|
|
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
|
|
|
|
# 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)
|