base64 module

The base64, base32, base16, base85 and ascii85 codecs plus the MIME helpers encodebytes/decodebytes are implemented: b64encode, b64decode, standard_b64encode, standard_b64decode, urlsafe_b64encode, urlsafe_b64decode, b32encode, b32decode, b32hexencode, b32hexdecode, b16encode, b16decode, b85encode, b85decode, z85encode, z85decode, a85encode, a85decode, encodebytes, decodebytes. Output bytes, error types and error messages match CPython 3.14 subject to the divergences below.

Not implemented

• base64.encode(input, output) and base64.decode(input, output), which read and write binary file objects. Monty's file objects have no read position, so the chunked read these perform has nothing to implement against — see open.md.
• The python -m base64 command line interface.

a85encode / a85decode

• wrapcol reaches CPython's max() and then a slice expression. Every non-int fails at one or the other, so what differs is which message you get, not whether the call fails. Monty matches CPython for a float ('float' object cannot be interpreted as an integer) and for a type that cannot be ordered against an int. A class defining both __gt__ and __index__ diverges: CPython gets past max() and range() to fail on i + wrapcol (unsupported operand type(s) for +), while Monty rejects it at the comparison, since it does not dispatch ordering dunders at all (see classes.md).

Input types

Encoders take bytes; decoders take bytes or an ASCII-only str. Monty has no bytearray, memoryview or array, so the "bytes-like object" the CPython docs describe is always bytes here.

binascii

binascii.Error, the hex pair (hexlify/unhexlify and their b2a_hex/a2b_hex aliases), the base64 pair (b2a_base64/a2b_base64) and crc32 are implemented. The uuencode and quoted-printable conversions (a2b_uu, b2a_uu, a2b_qp, b2a_qp) are absent and raise AttributeError.