add type annotations for indexer

[nominatim.git] / nominatim / tokenizer / token_analysis / generic.py

diff --git a/nominatim/tokenizer/token_analysis/generic.py b/nominatim/tokenizer/token_analysis/generic.py
index 2c720f1d6af9e38b93e6eea95f4ed70de866235a..3de915ba5254e1859976dd7e9842247df5a58b98 100644 (file)
--- a/nominatim/tokenizer/token_analysis/generic.py
+++ b/nominatim/tokenizer/token_analysis/generic.py
@@ -1,18 +1,56 @@
+# 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.
 """
 """
 Generic processor for names that creates abbreviation variants.
 """

-from collections import defaultdict

 import itertools
 
 import itertools
 

-from icu import Transliterator

 import datrie
 
 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
 
 ### Analysis section
 

-def create(norm_rules, trans_rules, config):
+def create(normalizer, transliterator, config):

     """ Create a new token analysis instance for this module.
     """
     """ Create a new token analysis instance for this module.
     """

-    return GenericTokenAnalysis(norm_rules, trans_rules, config['variants'])
+    return GenericTokenAnalysis(normalizer, transliterator, config)

 
 
 class GenericTokenAnalysis:
 
 
 class GenericTokenAnalysis:


@@ -20,91 +58,89 @@ class GenericTokenAnalysis:
         and provides the functions to apply the transformations.
     """
 
         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.
         """
 
     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)