add type annotations for token analysis

No annotations for ICU types yet.

nominatim/tokenizer/token_analysis/base.py

@@ -0,0 +1,45 @@
+# 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.
+"""
+Common data types and protocols for analysers.
+"""
+from typing import TypeVar, Mapping, List, Any
+
+from typing_extensions import Protocol
+
+
+T_config = TypeVar('T_config') # pylint: disable=invalid-name
+
+class Analyser(Protocol):
+    """ Instance of the token analyser.
+    """
+
+    def normalize(self, name: str) -> str:
+        """ Return the normalized form of the name. This is the standard form
+            from which possible variants for the name can be derived.
+        """
+
+    def get_variants_ascii(self, norm_name: str) -> List[str]:
+        """ Compute the spelling variants for the given normalized name
+            and transliterate the result.
+        """
+
+class AnalysisModule(Protocol[T_config]):
+    """ Protocol for analysis modules.
+    """
+
+    def configure(self, rules: Mapping[str, Any], normalization_rules: str) -> T_config:
+        """ Prepare the configuration of the analysis module.
+            This function should prepare all data that can be shared
+            between instances of this analyser.
+        """
+
+    def create(self, normalizer: Any, transliterator: Any, config: T_config) -> Analyser:
+        """ Create a new instance of the analyser.
+            A separate instance of the analyser is created for each thread
+            when used in multi-threading context.
+        """