From bf6ecf378a365f39ea144343d71010663cb7db85 Mon Sep 17 00:00:00 2001
From: Dylan Verheul <dylan@dyve.net>
Date: Sat, 24 Jan 2026 10:26:01 +0100
Subject: [PATCH 1/2] Add stricter Place Code validation

---
 src/euring/codes.py    | 12 ++++++++++++
 src/euring/fields.py   | 13 ++++++++++---
 tests/test_decoding.py | 11 +++++++++++
 3 files changed, 33 insertions(+), 3 deletions(-)

diff --git a/src/euring/codes.py b/src/euring/codes.py
index fa57eac..548b40b 100644
--- a/src/euring/codes.py
+++ b/src/euring/codes.py
@@ -1,3 +1,4 @@
+import re
 from collections.abc import Callable, Mapping
 from datetime import date
 from typing import Any
@@ -200,6 +201,17 @@ def parse_direction(value: str) -> int | None:
     return parsed
 
 
+_PLACE_CODE_RE = re.compile(r"^[A-Z]{2}([A-Z]{2}|[0-9]{2}|--)$")
+
+
+def parse_place_code(value: str) -> str:
+    """Validate the place code pattern (AA##, AAAA, or AA--)."""
+    value_str = f"{value}"
+    if not _PLACE_CODE_RE.match(value_str):
+        raise EuringConstraintException(f'Value "{value}" is not a valid place code format.')
+    return value_str
+
+
 def _parse_decimal_coordinate(value: str, *, max_abs: int, max_decimals: int, field_name: str) -> float:
     """Parse and validate a decimal latitude/longitude string."""
     try:
diff --git a/src/euring/fields.py b/src/euring/fields.py
index 583acc5..a8cb96d 100644
--- a/src/euring/fields.py
+++ b/src/euring/fields.py
@@ -42,6 +42,7 @@
     parse_latitude,
     parse_longitude,
     parse_old_greater_coverts,
+    parse_place_code,
 )
 from .field_schema import EuringField, EuringFormattedField, EuringLookupField
 from .types import (
@@ -173,8 +174,13 @@
         lookup=LOOKUP_ACCURACY_OF_DATE,
     ),
     EuringField(name="Time", key="time", type_name=TYPE_ALPHANUMERIC, length=4),
-    EuringLookupField(
-        name="Place Code", key="place_code", type_name=TYPE_ALPHANUMERIC, length=4, lookup=lookup_place_code
+    EuringFormattedField(
+        name="Place Code",
+        key="place_code",
+        type_name=TYPE_ALPHANUMERIC,
+        length=4,
+        parser=parse_place_code,
+        lookup=lookup_place_code,
     ),
     EuringFormattedField(
         name="Geographical Co-ordinates",
@@ -337,12 +343,13 @@
         required=False,
         parser=parse_longitude,
     ),
-    EuringLookupField(
+    EuringFormattedField(
         name="Current Place Code",
         key="current_place_code",
         type_name=TYPE_ALPHANUMERIC,
         length=4,
         required=False,
+        parser=parse_place_code,
         lookup=lookup_place_code,
     ),
     EuringField(name="More Other Marks", key="more_other_marks", type_name=TYPE_ALPHABETIC, required=False),
diff --git a/tests/test_decoding.py b/tests/test_decoding.py
index 3a09f2b..ee04a7b 100644
--- a/tests/test_decoding.py
+++ b/tests/test_decoding.py
@@ -9,6 +9,7 @@
     parse_direction,
     parse_geographical_coordinates,
     parse_old_greater_coverts,
+    parse_place_code,
 )
 from euring.exceptions import EuringConstraintException, EuringTypeException
 from euring.fields import EURING_FIELDS
@@ -180,6 +181,16 @@ def test_parse_direction_allows_hyphens(self):
         assert parse_direction("---") is None
         assert parse_direction("-") is None
 
+    def test_parse_place_code_allows_country_unknown_subdivision(self):
+        assert parse_place_code("NL--") == "NL--"
+
+    def test_parse_place_code_allows_numeric_subdivision(self):
+        assert parse_place_code("ES00") == "ES00"
+
+    def test_parse_place_code_rejects_invalid_pattern(self):
+        with pytest.raises(EuringConstraintException):
+            parse_place_code("N1--")
+
     def test_parse_direction_rejects_out_of_range(self):
         with pytest.raises(EuringConstraintException):
             parse_direction("360")

From 9da1b0edf5678db5a087f6338d4f88277b64d0ab Mon Sep 17 00:00:00 2001
From: Dylan Verheul <dylan@dyve.net>
Date: Sat, 24 Jan 2026 10:26:30 +0100
Subject: [PATCH 2/2] CHANGELOG

---
 CHANGELOG.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 901f888..d1cfb5c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@
 
 ## Unreleased
 
+- Add stricter Place Code validation (#99).
 - Parse raw values to values for all fields (#98).
 - Add constraints and tests for Direction (#97).
 - Improve support for Distance, Direction and Elapsed Time (#96).