minimum counts for tokens should always be 1

[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 f790dad27a24d9f11300ab1f6d78c147b829797b..1ed9bf4d383107e0c00a071d3f768057499f432e 100644 (file)
--- a/nominatim/tokenizer/token_analysis/generic.py
+++ b/nominatim/tokenizer/token_analysis/generic.py
@@ -7,151 +7,53 @@
 """
 Generic processor for names that creates abbreviation variants.
 """
 """
 Generic processor for names that creates abbreviation variants.
 """

-from collections import defaultdict, namedtuple
+from typing import Mapping, Dict, Any, Iterable, Iterator, Optional, List, cast

 import itertools
 import itertools

-import re

 
 

-from icu import Transliterator

 import datrie
 
 import datrie
 

-from nominatim.config import flatten_config_list

 from nominatim.errors import UsageError
 from nominatim.errors import UsageError

+from nominatim.data.place_name import PlaceName
+from nominatim.tokenizer.token_analysis.config_variants import get_variant_config
+from nominatim.tokenizer.token_analysis.generic_mutation import MutationVariantGenerator

 
 ### Configuration section
 
 
 ### Configuration section
 

-ICUVariant = namedtuple('ICUVariant', ['source', 'replacement'])
-
-def configure(rules, normalization_rules):
+def configure(rules: Mapping[str, Any], normalizer: Any, _: Any) -> Dict[str, Any]:

     """ Extract and preprocess the configuration for this module.
     """
     """ Extract and preprocess the configuration for this module.
     """

-    config = {}
+    config: Dict[str, Any] = {}

 
 

-    config['replacements'], config['chars'] = _get_variant_config(rules.get('variants'),
-                                                                  normalization_rules)
+    config['replacements'], config['chars'] = get_variant_config(rules.get('variants'),
+                                                                 normalizer)

     config['variant_only'] = rules.get('mode', '') == 'variant-only'
 
     config['variant_only'] = rules.get('mode', '') == 'variant-only'
 

-    return config
-
-
-def _get_variant_config(rules, normalization_rules):
-    """ Convert the variant definition from the configuration into
-        replacement sets.
-    """
-    immediate = defaultdict(list)
-    chars = set()
-
-    if rules:
-        vset = set()
-        rules = flatten_config_list(rules, 'variants')
-
-        vmaker = _VariantMaker(normalization_rules)
-
-        for section in rules:
-            for rule in (section.get('words') or []):
-                vset.update(vmaker.compute(rule))
-
-        # Intermediate reorder by source. Also compute required character set.
-        for variant in vset:
-            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)
-
-    return list(immediate.items()), ''.join(chars)
-
-
-class _VariantMaker:
-    """ Generater for all necessary ICUVariants from a single variant rule.
-
-        All text in rules is normalized to make sure the variants match later.
-    """
-
-    def __init__(self, norm_rules):
-        self.norm = Transliterator.createFromRules("rule_loader_normalization",
-                                                   norm_rules)
-
-
-    def compute(self, rule):
-        """ Generator for all ICUVariant tuples from a single variant rule.
-        """
-        parts = re.split(r'(\|)?([=-])>', rule)
-        if len(parts) != 4:
-            raise UsageError("Syntax error in variant rule: " + rule)
-
-        decompose = parts[1] is None
-        src_terms = [self._parse_variant_word(t) for t in parts[0].split(',')]
-        repl_terms = (self.norm.transliterate(t).strip() for t in parts[3].split(','))
-
-        # If the source should be kept, add a 1:1 replacement
-        if parts[2] == '-':
-            for src in src_terms:
-                if src:
-                    for froms, tos in _create_variants(*src, src[0], decompose):
-                        yield ICUVariant(froms, tos)
-
-        for src, repl in itertools.product(src_terms, repl_terms):
-            if src and repl:
-                for froms, tos in _create_variants(*src, repl, decompose):
-                    yield ICUVariant(froms, tos)
-
-
-    def _parse_variant_word(self, name):
-        name = name.strip()
-        match = re.fullmatch(r'([~^]?)([^~$^]*)([~$]?)', name)
-        if match is None or (match.group(1) == '~' and match.group(3) == '~'):
-            raise UsageError("Invalid variant word descriptor '{}'".format(name))
-        norm_name = self.norm.transliterate(match.group(2)).strip()
-        if not norm_name:
-            return None
-
-        return norm_name, match.group(1), match.group(3)
+    # 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']))

 
 

-
-_FLAG_MATCH = {'^': '^ ',
-               '$': ' ^',
-               '': ' '}
-
-
-def _create_variants(src, preflag, postflag, repl, decompose):
-    if preflag == '~':
-        postfix = _FLAG_MATCH[postflag]
-        # suffix decomposition
-        src = src + postfix
-        repl = repl + postfix
-
-        yield src, repl
-        yield ' ' + src, ' ' + repl
-
-        if decompose:
-            yield src, ' ' + repl
-            yield ' ' + src, repl
-    elif postflag == '~':
-        # prefix decomposition
-        prefix = _FLAG_MATCH[preflag]
-        src = prefix + src
-        repl = prefix + repl
-
-        yield src, repl
-        yield src + ' ', repl + ' '
-
-        if decompose:
-            yield src, repl + ' '
-            yield src + ' ', repl
-    else:
-        prefix = _FLAG_MATCH[preflag]
-        postfix = _FLAG_MATCH[postflag]
-
-        yield prefix + src + postfix, prefix + repl + postfix
+    return config

 
 
 ### Analysis section
 
 
 
 ### Analysis section
 

-def create(transliterator, config):
+def create(normalizer: Any, transliterator: Any,
+           config: Mapping[str, Any]) -> 'GenericTokenAnalysis':

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

-    return GenericTokenAnalysis(transliterator, config)
+    return GenericTokenAnalysis(normalizer, transliterator, config)

 
 
 class GenericTokenAnalysis:
 
 
 class GenericTokenAnalysis:


@@ -159,7 +61,8 @@ class GenericTokenAnalysis:
         and provides the functions to apply the transformations.
     """
 
         and provides the functions to apply the transformations.
     """
 

-    def __init__(self, to_ascii, config):
+    def __init__(self, norm: Any, to_ascii: Any, config: Mapping[str, Any]) -> None:
+        self.norm = norm

         self.to_ascii = to_ascii
         self.variant_only = config['variant_only']
 
         self.to_ascii = to_ascii
         self.variant_only = config['variant_only']
 


@@ -171,19 +74,51 @@ class GenericTokenAnalysis:
         else:
             self.replacements = None
 
         else:
             self.replacements = None
 

+        # set up mutation rules
+        self.mutations = [MutationVariantGenerator(*cfg) for cfg in config['mutations']]
+
+
+    def get_canonical_id(self, name: PlaceName) -> str:
+        """ Return the normalized form of the name. This is the standard form
+            from which possible variants for the name can be derived.
+        """
+        return cast(str, self.norm.transliterate(name.name)).strip()
+

 
 

-    def get_variants_ascii(self, norm_name):
+    def compute_variants(self, norm_name: str) -> List[str]:

         """ Compute the spelling variants for the given normalized name
             and transliterate the result.
         """
         """ 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: str,
+                                   iterable: Iterable[str]) -> Iterator[Optional[str]]:
+        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: str) -> Iterable[str]:

         baseform = '^ ' + norm_name + ' ^'
         baseform = '^ ' + norm_name + ' ^'

+        baselen = len(baseform)

         partials = ['']
 
         startpos = 0
         if self.replacements is not None:
             pos = 0
             force_space = False
         partials = ['']
 
         startpos = 0
         if self.replacements is not None:
             pos = 0
             force_space = False

-            while pos < len(baseform):
+            while pos < baselen:

                 full, repl = self.replacements.longest_prefix_item(baseform[pos:],
                                                                    (None, None))
                 if full is not None:
                 full, repl = self.replacements.longest_prefix_item(baseform[pos:],
                                                                    (None, None))
                 if full is not None:


@@ -207,24 +142,9 @@ class GenericTokenAnalysis:
 
         # No variants detected? Fast return.
         if startpos == 0:
 
         # No variants detected? Fast return.
         if startpos == 0:

-            if self.variant_only:
-                return []
-
-            trans_name = self.to_ascii.transliterate(norm_name).strip()
-            return [trans_name] if trans_name else []
-
-        return self._compute_result_set(partials, baseform[startpos:],
-                                        norm_name if self.variant_only else '')
-
-
-    def _compute_result_set(self, partials, prefix, exclude):
-        results = set()
+            return (norm_name, )

 
 

-        for variant in partials:
-            vname = (variant + prefix)[1:-1].strip()
-            if vname != exclude:
-                trans_name = self.to_ascii.transliterate(vname).strip()
-                if trans_name:
-                    results.add(trans_name)
+        if startpos < baselen:
+            return (part[1:] + baseform[startpos:-1] for part in partials)

 
 

-        return list(results)
+        return (part[1:-1] for part in partials)