Named tuples

Named tuples exist as a heap type but cannot be constructed by sandboxed Python code:

• collections.namedtuple — collections is not importable.
• typing.NamedTuple — exists as a marker only; subscripting / class inheritance does not produce a type (no class statement; see language.md).
• There is no builtin namedtuple factory.

Named tuples enter the sandbox in two ways: as sys.version_info, and as values passed in from the host via the MontyObject API.

Supported operations

• Indexing by integer: nt[0]. IndexError on out-of-range.
• Field access by name as an attribute: nt.major. AttributeError on unknown names.
• len(nt), iteration (for x in nt).
• Equality: nt == nt2 and nt == (a, b, c) — a named tuple equals a plain tuple with the same elements (matches CPython).
• Hashing: same hash as a plain tuple with the same elements; usable as a dict key or set element.
• repr(nt) — Name(field1=v1, field2=v2, ...) matching CPython.
• bool(nt) — True if non-empty, False if empty (tuple semantics).

NOT supported

• Slicing: nt[1:3] raises — __getitem__ only accepts integer keys. (CPython returns a plain tuple for slices.)
• Lookup by string key: nt["major"] raises TypeError: ... indices must be integers. Use attribute access instead.
• Named-tuple methods from CPython: ._replace(**kw), ._asdict(), ._make(iterable), ._fields, ._field_defaults, ._source.
• Concatenation / multiplication: nt + nt2, nt * 3 are not implemented (plain tuples support these; named tuples in Monty do not).
• Subclassing.