Add support for Cape Verde TIN

Fixes #387

stdnum/cv/__init__.py

@@ -0,0 +1,24 @@
+# __init__.py - collection of Cape Verde numbers
+# coding: utf-8
+#
+# Copyright (C) 2023 Leandro Regueiro
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+# 02110-1301 USA
+
+"""Collection of Cape Verde numbers."""
+
+# provide aliases
+from stdnum.cv import nif as vat  # noqa: F401

stdnum/cv/nif.py

@@ -0,0 +1,107 @@
+# nif.py - functions for handling Cape Verde NIF numbers
+# coding: utf-8
+#
+# Copyright (C) 2023 Leandro Regueiro
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+# 02110-1301 USA
+
+"""NIF (Número de Identificação Fiscal, Cape Verde tax number).
+
+This number consists of 9 digits, sometimes separated into three groups with
+three digits each to make it easier to read, like XXX XXX XXX.
+
+The first digit indicates the type of person:
+
+  * 1: Singular person, either resident or non resident.
+  * 2: Companies.
+  * 3: National entities.
+  * 4: International entities.
+  * 5: Other entities.
+
+The following six digits are either:
+
+  * The Bilhete de Identidade number, for singular resident persons, or
+  * A sequence automatically assigned, for all other cases.
+
+The last two digits are control digits.
+
+More information:
+
+* https://portondinosilhas.gov.cv/images/igrp-portal/img/documentos/EA834694B09A15FAE044002128A60A02.pdf
+* https://www.mf.gov.cv/documents/54571/273413/adenda_esclarecimentos_pdfs.pdf
+
+
+>>> validate('200129775')
+'200129775'
+>>> validate('200 144 731')
+'200144731'
+>>> validate('253.656.575')
+'253656575'
+>>> validate('12345')
+Traceback (most recent call last):
+    ...
+InvalidLength: ...
+>>> validate('VV3456789')
+Traceback (most recent call last):
+    ...
+InvalidFormat: ...
+>>> validate('923456789')
+Traceback (most recent call last):
+    ...
+InvalidComponent: ...
+>>> format('200 144 731')
+'200144731'
+"""  # noqa: E501
+
+from stdnum.exceptions import *
+from stdnum.util import clean, isdigits
+
+
+def compact(number):
+    """Convert the number to the minimal representation.
+
+    This strips the number of any valid separators and removes surrounding
+    whitespace.
+    """
+    return clean(number, ' -.').strip()
+
+
+def validate(number):
+    """Check if the number is a valid Cape Verde NIF number.
+
+    This checks the length and formatting.
+    """
+    number = compact(number)
+    if len(number) != 9:
+        raise InvalidLength()
+    if not isdigits(number):
+        raise InvalidFormat()
+    if number[0] not in ('1', '2', '3', '4', '5'):
+        raise InvalidComponent()
+    return number
+
+
+def is_valid(number):
+    """Check if the number is a valid Cape Verde NIF number."""
+    try:
+        return bool(validate(number))
+    except ValidationError:
+        return False
+
+
+def format(number):
+    """Reformat the number to the standard presentation format."""
+    return compact(number)