+# 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.
+"""
+Specialized processor for postcodes. Supports a 'lookup' variant of the
+token, which produces variants with optional spaces.
+"""
+
+from nominatim.tokenizer.token_analysis.generic_mutation import MutationVariantGenerator
+
+### Configuration section
+
+def configure(rules, normalization_rules): # pylint: disable=W0613
+ """ All behaviour is currently hard-coded.
+ """
+ return None
+
+### Analysis section
+
+def create(normalizer, transliterator, config): # pylint: disable=W0613
+ """ Create a new token analysis instance for this module.
+ """
+ return PostcodeTokenAnalysis(normalizer, transliterator)
+
+class PostcodeTokenAnalysis:
+ """ Detects common housenumber patterns and normalizes them.
+ """
+ def __init__(self, norm, trans):
+ self.norm = norm
+ self.trans = trans
+
+ self.mutator = MutationVariantGenerator(' ', (' ', ''))
+
+
+ def normalize(self, name):
+ """ Return the standard form of the postcode.
+ """
+ return name.strip().upper()
+
+
+ def get_variants_ascii(self, norm_name):
+ """ Compute the spelling variants for the given normalized postcode.
+
+ The official form creates one variant. If a 'lookup version' is
+ given, then it will create variants with optional spaces.
+ """
+ # Postcodes follow their own transliteration rules.
+ # Make sure at this point, that the terms are normalized in a way
+ # that they are searchable with the standard transliteration rules.
+ return [self.trans.transliterate(term) for term in
+ self.mutator.generate([self.norm.transliterate(norm_name)])]