split code into submodules

src/nominatim_db/tools/special_phrases/sp_csv_loader.py

@@ -0,0 +1,46 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+#
+# This file is part of Nominatim. (https://nominatim.org)
+#
+# Copyright (C) 2024 by the Nominatim developer community.
+# For a full list of authors see the git log.
+"""
+    Module containing the SPCsvLoader class.
+
+    The class allows to load phrases from a csv file.
+"""
+from typing import Iterable
+import csv
+import os
+
+from nominatim_core.errors import UsageError
+from .special_phrase import SpecialPhrase
+
+class SPCsvLoader:
+    """
+        Handles loading of special phrases from external csv file.
+    """
+    def __init__(self, csv_path: str) -> None:
+        self.csv_path = csv_path
+
+
+    def generate_phrases(self) -> Iterable[SpecialPhrase]:
+        """ Open and parse the given csv file.
+            Create the corresponding SpecialPhrases.
+        """
+        self._check_csv_validity()
+
+        with open(self.csv_path, encoding='utf-8') as fd:
+            reader = csv.DictReader(fd, delimiter=',')
+            for row in reader:
+                yield SpecialPhrase(row['phrase'], row['class'], row['type'], row['operator'])
+
+
+    def _check_csv_validity(self) -> None:
+        """
+            Check that the csv file has the right extension.
+        """
+        _, extension = os.path.splitext(self.csv_path)
+
+        if extension != '.csv':
+            raise UsageError(f'The file {self.csv_path} is not a csv file.')