datetime module

Provides four classes: date, datetime, timedelta, timezone. The module-level time, tzinfo, and MINYEAR / MAXYEAR symbols are not exposed.

date

Constructor: date(year, month, day). Attributes: year, month, day. Methods: isoformat, strftime, replace, weekday, isoweekday.

Class methods today(), fromisoformat(), fromisocalendar(), fromtimestamp(), fromordinal() are not implemented. today() is missing because the sandbox has no access to the host clock.

datetime

Constructor: datetime(year, month, day, hour=0, minute=0, second=0, microsecond=0, tzinfo=None, *, fold=0). fold is accepted and validated (must be 0 or 1) for CPython argument-parsing parity but does not affect the stored value — Monty does not track DST-fold disambiguation. Attributes: year, month, day, hour, minute, second, microsecond, tzinfo. Methods: isoformat, strftime, replace, weekday, isoweekday, date, timestamp.

Class methods supported: now(tz=None), strptime(date_string, format), fromisoformat(date_string).

• now() reaches the host for the current time (the only "live" datetime call); it yields an external call.
• now(tz) returns a datetime whose tzinfo is == the input timezone but not is it: the original tzinfo object isn't threaded through the OS-call resume, so a fresh timezone is reconstructed from the offset/name on the return path.
• utcnow() (the deprecated class method) and today() are not implemented.
• combine(), fromtimestamp(), fromordinal(), utcfromtimestamp() are not implemented.

Subclassing datetime is not possible (no class statement; see language.md).

datetime.replace() and date.replace() accept only keyword arguments in Monty. CPython accepts positional args too (d.replace(2025) is valid in CPython 3.14). Calling with positionals in Monty raises TypeError: replace expected at most 0 arguments, got N.

timedelta

Constructor: timedelta(days=0, seconds=0, microseconds=0, minutes=0, hours=0). The CPython milliseconds and weeks parameters are not supported. Attributes: days, seconds, microseconds. No methods (.total_seconds() is not implemented).

Arithmetic (+, -, *, comparisons) works between timedeltas and between datetime/date and timedelta. Division and floor-division of two timedeltas is not implemented.

timezone

Constructor: timezone(offset, name=None) where offset is a timedelta. Attributes: offset, name.

timezone.utc and timezone.min / timezone.max class constants are not defined. The abstract tzinfo base class is not exposed.

Formatting

strftime supports the directives that map onto Rust's chrono formatting; locale-specific directives (%c, %x, %X, %p) follow Rust's defaults rather than the C locale and may differ from CPython. %Z always emits an empty string for naive datetimes.