Both keep the same Typikon and read it a little differently, and until now
this library silently picked one reading and called it the Typikon. Two
differences are modelled, each one visible in the output and named in the
day's reason:
- The Protection of the Theotokos is a great feast in Slavic usage. Greek
practice ranks it lower, and the Church of Greece keeps it on 28 October
besides. This has teeth: rank is what lifts a Wednesday or Friday fast.
- Greek practice admits fish on any day of the Nativity Fast but Wednesday
and Friday until 17 December; Slavic practice keeps fish to Saturdays and
Sundays throughout.
Every jurisdiction carries the usage its books follow, and --tradition
overrides it for a parish that does not match its jurisdiction's default. The
difference in the calendar lives in a data overlay compiled in beside the
common menologion, which is where a local church's own commemorations would
go; the difference in the fast lives in the rule, because that is where it is.
Each rank also now carries the mark the books print beside it, circled cross,
cross and Jerusalem cross for great, vigil and polyeleos. Unicode has no glyph
for the polyeleos sign, a cross over a half-circle, so the Jerusalem cross
stands in as digital calendars generally settle on.
The engine is the same; only the front door is new. pyo3 behind an optional
feature, maturin for the wheel, and the bindings mirror DayJson rather than Day
because DayJson is already the shape front ends read and the one that has to stay
still. to_dict() therefore gives exactly what --json gives, and a test holds the
two to that.
That test earned its place immediately. The bindings were calling
jurisdictions::resolve(None), which answers with a built-in default that knows
nothing about the machine, so Python was reckoning by the New Calendar while the
command line on the same box reckoned by ROCOR — every field downstream of the
calendar differed, including the fast. They now take the same two steps main.rs
takes, and agree field for field on Pascha, the Nativity and Theophany.
The wheel is abi3, so one build serves 3.9 upward rather than one per
interpreter. That costs the datetime C API, which the limited API does not
expose, so a date is read through its attributes instead — which incidentally
makes datetime.datetime work as well as datetime.date. Constructing dates is
unaffected, pyo3 calls Python's own constructor for that.
panic = "abort" comes out of the release profile. An extension module has to be
able to unwind a panic into a Python exception; aborting would take the
interpreter down with it. The CLI keeps the same behaviour it always had, a
panic there just unwinds now.
Mixed layout so the wheel can carry py.typed and a stub file, which a bare
extension module has nowhere to put. mypy --strict is clean against the stubs
and catches a deliberate error, so the Typing :: Typed classifier is not a claim
about nothing.
--format takes text, json, csv, tsv or ics. --json and --ics stay as
shorthand, because the widgets already call them.
csv and tsv are RFC 4180 quoted, one header row, one row per day, with
commemorations joined by a semicolon: a cell that is itself a table is worse
than a cell you have to split. --list-fields prints the twenty columns,
--fields picks a subset in the order you name them, and a column that does
not exist is caught before anything is printed rather than silently emitting
an empty cell.
--no-emoji drops the glyphs from every format, including the emoji field in
the JSON, and collapses the column in the text output rather than leaving a
hole where a glyph used to be.
Python was never the house language here: the mw-* desktop surface it came
from is 39 bash scripts and was exactly one Python script, the one this was
extracted from. What it cost was distribution, a widget dependency that
needed pipx and a Python floor, and 24ms of interpreter startup before a line
of the program ran.
The port is verified rather than asserted. Both implementations were run over
199,446 day-records, 26 jurisdictions across 21 years, with every field of
every record required to match; the JSON, the iCalendar and 480 renderings of
the text output are identical too. examples/dump.rs is the harness.
What the type system actually buys, which is less than the usual claim and
more than nothing:
- Level is an ordered enum, strictest first, so reads as 'a is
stricter' and relaxed_to() is the one place a feast can lift a fast. No
rule can get the direction backwards.
- Date is a newtype over the Julian Day Number and JulianDate is a separate
type, so a civil date and an ecclesiastical one cannot be mixed up. That
confusion is the single most common way calendar code goes wrong.
- Octets is a newtype in the iCalendar folder, because the bug it replaced
counted characters against a limit RFC 5545 states in octets.
- Movables is a struct, not a map, so a mistyped key is a compile error
rather than a None at the far end of the program.
Of the six defects an adversarial review found in the Python, exactly one had
a shape a type system would have caught. The rest were logic, and the tests
came with them.
The menologion is compiled in with include_str!, so the binary answers on its
own: 930KB, no runtime, 1.2ms to start against Python's 36ms.
An adversarial pass found the rules throwing away the feast rank that
describe() computes, in exactly the seasons where it decides the answer.
- A saint of vigil or polyeleos rank now lifts a weekday of a fast, to wine
and oil inside the Great Fast and as far as fish in the three lesser
ones. This is why the printed calendars mark so many Wednesdays in the
Nativity Fast; 74 days across 2020-2030 were being reported stricter than
any published calendar keeps them, St Nicholas and the Forty Martyrs of
Sebaste among them.
- The Annunciation was tested after Great Friday and Great Saturday, so on
the years it lands there it vanished into them entirely -- the Great Feast
of the Incarnation demoted to a bullet, reported as a total fast, and its
rank overwritten with the lesser movable one the rules then read. It is
now tested first and lifts those days to wine and oil. Five such years
this century on the Gregorian paschalion, seven on the Julian.
- Lazarus Saturday and Palm Sunday belonged to no season at all, sitting
between the Forty Days and Great Week. Any rule keying on the season fell
through, so Byzantine Catholic jurisdictions reported a meat glyph and
'no fast' on Palm Sunday.
- The eves of the Nativity and Theophany are relaxed to wine and oil when
they fall on a weekend, which ruthenian.py already implemented and this
module did not.
Also: iCalendar folded on characters where RFC 5545 counts octets, so an
emoji put lines up to 80 octets over a 75-octet limit; a malformed --date
printed a traceback; the overlaid menologion was rebuilt for every single day
asked about; the Nativity of the Forerunner was ranked below its class.
Fourteen new tests, each one able to fail. The old sweep asserted only
all(d.fast), and 'none' is a truthy string.
Feasts, seasons and the fast for twenty-three jurisdictions, derived from
the paschalion and the fixed calendar so it needs no network and cannot go
stale.
The three things calendar code usually conflates are kept apart: the
paschalion that gives Pascha, the menologion the fixed feasts are read on,
and the fasting rule that is kept. Almost every Orthodox Church keeps the
Julian Paschalion; what divides them is the menologion, so one file of
commemorations indexed by ecclesiastical date serves old and new calendars
alike.
Six fasting levels rather than three, because the difference between
xerophagy and wine-and-oil is the difference the books actually make. Level
and obligation are carried separately: the Orthodox rule reports everything
as customary, and Ruthenian particular law reports both how a day is kept
and the far smaller minimum that binds.
The menologion covers all 366 days and is dedicated to the public domain.
Sets published by someone else are fetched, never redistributed.
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