maths.is_ipv6_address_valid
===========================

.. py:module:: maths.is_ipv6_address_valid

.. autoapi-nested-parse::

   Validate IPv6 addresses (full and compressed forms).

   References:
   - Wikipedia: https://en.wikipedia.org/wiki/IPv6_address
   - RFC 4291: https://tools.ietf.org/html/rfc4291

   Rules implemented (subset of RFC 4291):
   - Hex groups are 1-4 hex digits (0-9, a-f, A-F).
   - Exactly 8 groups in total. A single '::' may compress one or more groups of
     zeros. No more than one '::' is allowed.
   - No leading/trailing single ':' (e.g., ':1:2::' is invalid).
   - Does NOT support IPv4-mapped endings like '::ffff:192.0.2.128'.

   Examples (doctests):

   >>> is_ipv6_address_valid("2001:0db8:85a3:0000:0000:8a2e:0370:7334")
   True
   >>> is_ipv6_address_valid("2001:db8:85a3:0:0:8A2E:0370:7334")
   True
   >>> is_ipv6_address_valid("2001:db8:85a3::8A2E:0370:7334")  # '::' compresses two groups
   True
   >>> is_ipv6_address_valid("::1")  # loopback, 7 groups compressed
   True
   >>> is_ipv6_address_valid("2001:db8::")  # trailing compression is OK
   True
   >>> is_ipv6_address_valid("::")  # all groups compressed
   True

   Invalids:

   >>> is_ipv6_address_valid("")  # empty
   False
   >>> is_ipv6_address_valid("2001:db8:85a3:::8a2e:370:7334")  # multiple '::'
   False
   >>> is_ipv6_address_valid("2001:db8:85a3:0:0:8a2e:370:7334:abcd")  # 9 groups
   False
   >>> is_ipv6_address_valid("2001:db8:85a3:0:0:8a2e:0370:g334")  # non-hex char
   False
   >>> is_ipv6_address_valid("2001:db8:85a3:0:0:8a2e:0370:")  # trailing ':'
   False
   >>> is_ipv6_address_valid(":2001:db8::1")  # leading ':'
   False
   >>> is_ipv6_address_valid("a::b:c:d:e:f:g:h")  # '::' compresses zero groups (already 8)
   False
   >>> is_ipv6_address_valid("1::1:1:1:1:1:1:1")  # same idea; zero groups compressed
   False



Attributes
----------

.. autoapisummary::

   maths.is_ipv6_address_valid._HEX_DIGITS
   maths.is_ipv6_address_valid.ip


Functions
---------

.. autoapisummary::

   maths.is_ipv6_address_valid._is_valid_group
   maths.is_ipv6_address_valid.is_ipv6_address_valid


Module Contents
---------------

.. py:function:: _is_valid_group(group: str) -> bool

   Return True iff group is 1-4 hex digits.
   Args:
       group (str): The hex group to validate.

   Returns:
       bool: True if the group is 1-4 hex digits, False otherwise.

   Examples:

   >>> _is_valid_group("1")
   True
   >>> _is_valid_group("abcd")
   True
   >>> _is_valid_group("12345")  # too long
   False
   >>> _is_valid_group("g")  # non-hex character
   False


.. py:function:: is_ipv6_address_valid(address: str) -> bool

   Return True iff `address` is a valid IPv6 address in full or compressed form.

   See module docstring for rules and doctests.


.. py:data:: _HEX_DIGITS

.. py:data:: ip