On 26.02.2024 15:26, Mike Sanders wrote:
>
> So tell me, what are you coding these days? Haven't seen much from you
> lately...

Wasn't it you who asked me (probably in the Awk newsgroup) to create
a web page (or use github) to post all my tools? - If so then I'm
surprised that you're asking again since I already told you that I
don't post my personal projects unless there's a concrete demand.

Have you any concrete demands for some code? - The please tell me
and I'll see whether I can provide something for you.

Janis

PS: I acknowledge if you seem to have some urge to post lots of code
(as I recall from the Awk NG), and that's fine - despite I'd wished
you'd take more care in quality, but since it's your code you define
the rules for your code (amount, frequency, quality). From me you'll
get hints and suggestions, and that's all.

On 26.02.2024 15:32, Mike Sanders wrote:
> Janis Papanagnou <janis_papanagnou+ng@hotmail.com> wrote:
>
>> And both dates, western and eastern, are anyway arbitrary. But if you
>> decide to neglect the existing facts, either by wrongly assuming that
>> there's only one "correct" Easter date, or by (arrogantly?) presuming
>> that one is more correct than the other, then you are discriminating
>> Christian folks that follow the one [arbitrary] definition (or the
>> other).
>
> And what's this? c'mon now, there's nothing arrogant or presumptuous here.
> I'm not discriminating against anyone (I'm Catholic if it makes a difference).
> Now then - don't start an argument where there is none...

While it may be personal arrogance (I can't tell; that's why I had put
it in parenthesis and with a question mark) I had more the often
observed "Western Arrogance" in mind. The country I'm living in is no
exception here! Sadly we can observe (more often than desirable) that
other cultures than the ones we are used to or living in are ignored,
their culture despised or neglected.

Speaking (in general contexts), say, only about male people will
discriminate the female ones. Considering only the sexually straight
people (is that word correct?) will discriminate the "LGBT..." folks.
Disregarding non-Christian religions will discriminate the majority
of religious people in the world. And if Christians exclude the
Orthodox Christians it's also a discrimination.

In case of the calendar issues even an unnecessary discrimination.

Whether you are a Catholic or not might explain a preference, or may
make some ignorance concerning other cultures understandable; I can't
tell, and it's not the relevant point when we're speaking about any
objective discrimination.

Janis

've just noticed I was formulating it as if it was your code. Of course
it was addressed at the author of the code. My apologies!

On 26.02.2024 16:17, Janis Papanagnou wrote:
> On 26.02.2024 15:46, David Brown wrote:
>>
>> Yes, I realise that's likely to be a problem here. For variables that
>> exist solely to break up a long complicated calculation into manageable
>> parts, good names are hard or impossible.
>>
>> However, I would guess - without having looked at the details of the
>> algorithm - that this could be split into parts that are a bit clearer,
>
> Unfortunately not, I fear.
>
>> and at least some of the variables could then have names showing what's
>> going on. You might have the offset into the lunar month, or the number
>> of days in February, or a boolean for before/after the spring equinox.
>
> You seem to have chosen a source where "Spencer's" algorithm is
> described. In a corresponding Wikipedia article (here in German:
> e.g. https://de.wikipedia.org/wiki/Spencers_Osterformel)
> you find the same non-descriptive names.
>
>>
>> If the expressions can only be split in somewhat arbitrary positions,
>> and therefore the variables have arbitrary and meaningless names, so be
>> it. But if it is possible and practical to do better, then I'd
>> recommend that.
>
> If you put in a reference to the document source - while not
> explaining anything - that might suffice. Otherwise you'd have
> to spend more effort describing the variables in detail.
>
> Janis
>

porkchop@invalid.foo (Mike Sanders) writes:
>David Brown <david.brown@hesbynett.no> wrote:
>
>> Don't use "int" when you mean "bool". That applies to parameters,
>> return types, and variables.
>
>But I dont mean bool, I mean int, because the function (well my
>private code at any rate) now includes other Holi/Holy days:
>
>int foo(const struct tm *now, int hDay);

I would expect that an enumeration would be superior
to an 'int' for this purpose.

On 26/02/2024 15:38, Mike Sanders wrote:
> David Brown <david.brown@hesbynett.no> wrote:
>
>> Don't use "int" when you mean "bool". That applies to parameters,
>> return types, and variables.
>
> But I dont mean bool, I mean int, because the function (well my
> private code at any rate) now includes other Holi/Holy days:
>
> int foo(const struct tm *now, int hDay);
>
> switch (hDay)...
>
> But you all still raise some good points.
>

I can only comment on the code you've given. And "isLeapYear()", and
"isEasterOrGoodFriday()" should both return "bool". The parameter
"checkGoodFriday" should be bool too. (Actually, it should be scraped
and the function split, as discussed on another branch.)

And if you are returning "holiday type" from a function, it should not
be "int" either - make it return an enumerated type.

On Mon, 26 Feb 2024 11:45:36 +0100, David Brown wrote:

> On 25/02/2024 18:39, Lew Pitcher wrote:
>> On Sat, 24 Feb 2024 21:15:56 +0000, Mike Sanders wrote:
>>
>>> Calculate the date of Easter Sunday or Good Friday:
>>>
>>> https://busybox.neocities.org/notes/is-easter-or-goodfriday.txt
>>
>> I don't have the expertise to discuss whether or not your code
>> properly implements the calculations necessary to determine the
>> date of Good Friday and/or Easter. However, I /do/ have some
>> expertise on writing understandable code.
>>
>> My suggestions, with respect to your program, would be to
[snip]
>> b) Don't place your calculations /in/ the object initializations.
>> Doing so obfuscates the intent of the logic, and makes
>> problem determination and resolution difficult.
>
> I'd disagree with that one. Initialise your variables when you have
> something to put in them, and that is often a calculated value.

I base my suggestion on the OP's source:
int isEasterOrGoodFriday(const struct tm *now, int checkGoodFriday) {

int Y = now->tm_year + 1900; // correcting the year
int a = Y % 19;
int b = Y / 100;
int c = Y % 100;
int d = b / 4;
int e = b % 4;
int f = (b + 8) / 25;
int g = (b - f + 1) / 3;
int h = (19 * a + b - d - g + 15) % 30;
int i = c / 4;
int k = c % 4;
int L = (32 + 2 * e + 2 * i - h - k) % 7;
int m = (a + 11 * h + 22 * L) / 451;
int month = (h + L - 7 * m + 114) / 31;
int day = ((h + L - 7 * m + 114) % 31) + 1;

if (checkGoodFriday) {
[rest of code elided]

The program code /depends/ on the specific order of
the declarations: <<Y>> /must/ be declared before <<a>>,
<<a>> /must/ be declared before <<h>>, etc.

If some good-meaning (or unknowledgable) maintainer decides to
reorder or consolidate the above declarations, the program
either fails or gives erroneous results.

The OP embedded the /logic/ of the program within the declarations.
That, to me. is /not/ good programming.

Hope this helps clarify my earlier remarks.
--
Lew Pitcher
"In Skills We Trust"

On 26/02/2024 17:10, Janis Papanagnou wrote:
> On 26.02.2024 15:32, Mike Sanders wrote:
>> Janis Papanagnou <janis_papanagnou+ng@hotmail.com> wrote:
>>
>>> And both dates, western and eastern, are anyway arbitrary. But if you
>>> decide to neglect the existing facts, either by wrongly assuming that
>>> there's only one "correct" Easter date, or by (arrogantly?) presuming
>>> that one is more correct than the other, then you are discriminating
>>> Christian folks that follow the one [arbitrary] definition (or the
>>> other).
>>
>> And what's this? c'mon now, there's nothing arrogant or presumptuous here.
>> I'm not discriminating against anyone (I'm Catholic if it makes a difference).
>> Now then - don't start an argument where there is none...
>
> While it may be personal arrogance (I can't tell; that's why I had put
> it in parenthesis and with a question mark) I had more the often
> observed "Western Arrogance" in mind. The country I'm living in is no
> exception here! Sadly we can observe (more often than desirable) that
> other cultures than the ones we are used to or living in are ignored,
> their culture despised or neglected.
>
> Speaking (in general contexts), say, only about male people will
> discriminate the female ones. Considering only the sexually straight
> people (is that word correct?) will discriminate the "LGBT..." folks.
> Disregarding non-Christian religions will discriminate the majority
> of religious people in the world. And if Christians exclude the
> Orthodox Christians it's also a discrimination.
>
> In case of the calendar issues even an unnecessary discrimination.
>
> Whether you are a Catholic or not might explain a preference, or may
> make some ignorance concerning other cultures understandable; I can't
> tell, and it's not the relevant point when we're speaking about any
> objective discrimination.
>
> Janis
>

"Arrogance" is one possibility. But people may fail to include a given
group for many different reasons, including (but not limited to) :

1. Ignorance. Maybe the OP knows little or nothing about the Eastern
Orthodox churches and when they have Easter. My guess is that many who
know that much, do not know about Oriental Orthodox churches, and these
are different from Eastern Orthodox, and that some of these use the
Easter date from Western Christian (Protestant and Catholic) tradition,
and some use Eastern Orthodox Easter. Then there are other Christian
groups such as Jehovah's Witnesses that do not celebrate Easter at all,
and there are not doubt many others that I have never heard of that do
do things somewhat differently.

2. Simplification. You can't cover /everything/.

3. Local bias. If you are involved in a particular Church, then that
determines the Easter of relevance to you. Many countries will also
have a strong bias towards one interpretation of Easter - perhaps for
public holidays, school terms, or other purposes.

4. Lack of thought or consideration - people don't always think things
through or consider all implications of things they write. That does
not make them arrogant or bigoted - it just makes them a normal,
fallible human.

5. Lack of relevance. If the code was just some sample C code for
learning the language, details of what it is actually calculating don't
matter in the context.

It might have been better for the OP to use "The Catholic Church Easter"
rather than just "Easter", but I don't think it is fair to suggest a
particular arrogance (much less to imply bigotry of some kind as you do
here) on the part of the OP.

(I think it is a good thing to take a stand against bigotry when you see
it, but it is not helpful to go searching for it where it is not present.)

Lawrence D'Oliveiro <ldo@nz.invalid> writes:

> On Sat, 24 Feb 2024 21:15:56 -0000 (UTC), Mike Sanders wrote:
>
>> Calculate the date of Easter Sunday or Good Friday:
>
> Did you know that one of the requirements of the rules was that Easter
> would never coincide with Passover? Because the sight of Christians
> celebrating together with Jews was seen as heretical or something ...

That's an Eastern Orthodox rule, not Western. Last year (western)
Easter was April 9, while Passover was April 5 through 13 (this year
they don't overlap).

Lawrence D'Oliveiro <ldo@nz.invalid> writes:

> On Sat, 24 Feb 2024 23:57:16 +0100, Janis Papanagnou wrote:
>
>> ... and that there's not a unique definition of Easter.
>
> Easter, Christmas ... both ancient pagan festivals co-opted by the
> Christians and given an invented meaning under their ideology, for their
> own propaganda purposes.

While that unquestionably true of Christmas, Easter very clearly comes
from Passover. It's true that in German-derived languages the name comes
from a Germanic goddess, and some countries have some traditions taken
from there as well, but that doesn't change the origin.

> Just like they took a lot of existing pagan deities (e.g. in Celtic lands)
> and reinvented them as “saints”.

Scott Lurndal <scott@slp53.sl.home> wrote:

>>int foo(const struct tm *now, int hDay);
>
> I would expect that an enumeration would be superior
> to an 'int' for this purpose.

Just now getting around to thinking of that to be honest
Scott (seems you're step ahead of me), but enums are
great in my thinking, consider:

enum weekdays { Sun, Mon, Tue, Wed, Thu, Fri, Sat };

if (Wed > Sun) { ... }

Nice & easy to read yeah?

--
:wq
Mike Sanders

porkchop@invalid.foo (Mike Sanders) writes:
>Scott Lurndal <scott@slp53.sl.home> wrote:
>
>>>int foo(const struct tm *now, int hDay);
>>
>> I would expect that an enumeration would be superior
>> to an 'int' for this purpose.
>
>Just now getting around to thinking of that to be honest
>Scott (seems you're step ahead of me), but enums are
>great in my thinking, consider:
>
>enum weekdays { Sun, Mon, Tue, Wed, Thu, Fri, Sat };
>
>if (Wed > Sun) { ... }
>
>Nice & easy to read yeah?

When you're working with dates, wednesday both preceeds
and follows sunday; so your if statement is logically
ambiguous.

Often, struct tm is useful for representing date/times
(unless you need year values 12024 or more years before present).

seconds [0-59]
minutes [0-59]
hours [0-23]
day [1-31]
month [0-11]
year [INT_MIN - INT_MAX]
wday [0-6] /* day of week */
yday [0-365] /* day of year */
isdst [-1,0,1] /* DST flag */

In any case, your 'hday' would have enumerated a
list of holidays, right? Where ordering wouldn't
be a prime criteria, rather the usefulness of an
enumeration would be in readability and maintainabilty
of the code.

Scott Lurndal <scott@slp53.sl.home> wrote:

> In any case, your 'hday' would have enumerated a
> list of holidays, right? Where ordering wouldn't
> be a prime criteria, rather the usefulness of an
> enumeration would be in readability and maintainabilty
> of the code.

Likely something close to (beware word-wrap) the following:

#define MAXNODES 6000

int foo(const struct tm *now, this, that, FILE *file) {

int totalDays = 366;
int count = 0;

BLOCK *nodes = (BLOCK *)malloc(MAXNODES * sizeof(BLOCK));
if (!nodes) return eMsg(errALLOC, 0);

temp_date = *now;

if (ops.hly) {
for (int j = temp_date.tm_mday; j <= totalDays && count < MAXNODES; j++) {
BLOCK tmp = putHoliday(tmp_date, ENUM_WILL_BE_PLACED_HERE);
if (tmp) {
nodes[count] = tmp;
temp_date = addDays(tmp_date, 1); // so we can see ahead of the curve...
count++;
}
}
}

if (count) {
for (int q = 0; q < count; q++)
fprintf(file, "%s whatever", node[q].member);
}

free(nodes); // etc...
return 0;

}

BLOCK putHoliday(const struct tm *now, ENUM_WILL_BE_PLACED_HERE) {

// you get the idea i'm guessing

}

struct tm addDays(struct tm date, int days) {
date.tm_mday += days; // add days to the current date
mktime(&date); // normalize date
return date;
}

--
:wq
Mike Sanders

On Mon, 26 Feb 2024 11:24:29 -0700, Joe Pfeiffer wrote:

> Lawrence D'Oliveiro <ldo@nz.invalid> writes:
>
>> Easter, Christmas ... both ancient pagan festivals co-opted by the
>> Christians and given an invented meaning under their ideology, for
>> their own propaganda purposes.
>
> While that unquestionably true of Christmas, Easter very clearly comes
> from Passover.

Easter bunny? Eggs? Both fertility symbols, associated with (northern)
spring and the beginning of the planting season? And both with origins
older than Christianity and Judaism combined?

Somehow I doubt it.

Lawrence D'Oliveiro <ldo@nz.invalid> writes:
>On Mon, 26 Feb 2024 11:24:29 -0700, Joe Pfeiffer wrote:
>
>> Lawrence D'Oliveiro <ldo@nz.invalid> writes:
>>
>>> Easter, Christmas ... both ancient pagan festivals co-opted by the
>>> Christians and given an invented meaning under their ideology, for
>>> their own propaganda purposes.
>>
>> While that unquestionably true of Christmas, Easter very clearly comes
>> from Passover.
>
>Easter bunny? Eggs? Both fertility symbols, associated with (northern)
>spring and the beginning of the planting season? And both with origins
>older than Christianity and Judaism combined?
>
>Somehow I doubt it.

March was the first month of the year in Roman times (which is why september
is derived from the latin for seven). It's likely that there were a
number of pagen festivals in the northern hemisphere spring associated
with rebirth (of the year, of the crops, etc).

On Mon, 26 Feb 2024 20:06:44 GMT, Scott Lurndal wrote:

> porkchop@invalid.foo (Mike Sanders) writes:
>
>>if (Wed > Sun) { ... }
>>
>>Nice & easy to read yeah?
>
> When you're working with dates, wednesday both preceeds and follows
> sunday; so your if statement is logically ambiguous.

There is a term for that: it’s “modulo arithmetic”.

On Mon, 26 Feb 2024 11:45:36 +0100, David Brown <david.brown@hesbynett.no>
wrote in <urhq4h$2g5oc$1@dont-email.me>:

> On 25/02/2024 18:39, Lew Pitcher wrote:
>> On Sat, 24 Feb 2024 21:15:56 +0000, Mike Sanders wrote:
>>
>>> Calculate the date of Easter Sunday or Good Friday:
>>>
>>> https://busybox.neocities.org/notes/is-easter-or-goodfriday.txt
>>
>> I don't have the expertise to discuss whether or not your code properly
>> implements the calculations necessary to determine the date of Good
>> Friday and/or Easter. However, I /do/ have some expertise on writing
>> understandable code.
>>
>> My suggestions, with respect to your program, would be to a) name your
>> objects with relevant, understandable names
>> You code uses quite a lot of meaningless one-letter objects, and it
>> is difficult to keep track of the purpose of the calculations using
>> them.
>
> I agree here.
>
> I'd also avoid single-letter capital letter variables, and avoid
> single-letter variables that are easily misread (so don't use "L" or
> "O", big or small). Single-letter variables are fine if their scope is
> small and their meaning is clear - such as "i" for a loop variable, and
> "x" and "y" for coordinates.
>
> Good names here, together with some comments, would go a long way to
> making it possible to understand your algorithm here. Links to web
> pages for reference are useful (and it's always polite to give your
> references), but remember that web pages don't last for ever - try to
> make your code stand alone as code, or at least have enough comments to
> cover the information.
>
>> b) Don't place your calculations /in/ the object initializations.
>> Doing so obfuscates the intent of the logic, and makes problem
>> determination and resolution difficult.
>
> I'd disagree with that one. Initialise your variables when you have
> something to put in them, and that is often a calculated value.
>
>
>> Otherwise, it /appears/ to do the job. Good first attempt.
>
> Some other suggestions:
>
> Don't use "int" when you mean "bool". That applies to parameters,
> return types, and variables.
>
> Don't have one function that appears to do two different things. It's
> much better to have "isEaster()" and "isGoodFriday()" functions. Clearly
> these are heavily related, so have a static helper function that does
> the common calculations.
>
> Consider making and using several general functions, rather than having
> a single impenetrable function. You might have a "numberOfDaysInYear()"
> function, and functions for converting (day, month) pairs back and forth
> to the number of days since the first of January. You can have lunar
> calculations also based on the number of days from a given starting
> point (perhaps using Unix epoch time rather than struct tm). Then you
> can have a "findEaster()" function that returns the date of Easter for a
> given year as the number of days from the first of January.

ncal(1) has the -e and -o options for both Easters. I went looking for
the source of the Easter-computation code, found one copy here:

https://github.com/lattera/freebsd/blob/master/lib/libcalendar/easter.c

On Ubuntu with source repositories enabled, one can get the BSD
ncal (with its bundled libcalendar) with

$ apt-get source ncal

I really wish the function easterg() was commented better.

/* Compute Easter Sunday in Gregorian Calendar */
date *
easterg(int y, date *dt)
{ int c, i, j, k, l, n;

n = y % 19;
c = y / 100;
k = (c - 17) / 25;
i = (c - c/4 -(c-k)/3 + 19 * n + 15) % 30;
i = i -(i/28) * (1 - (i/28) * (29/(i + 1)) * ((21 - n)/11));
j = (y + y/4 + i + 2 - c + c/4) % 7;
l = i - j;
dt->m = 3 + (l + 40) / 44;
dt->d = l + 28 - 31*(dt->m / 4);
dt->y = y;
return (dt);
}

The code is 27 years old. I will not pretend to understand it. (Yet?)

Feed the easterg() function to ChatGPT, and it will pretend
to explain it. (Is it correct? Beats me. But it did
introduce me to the concept of the "Computus"[*].)

[*] Described in here: https://en.wikipedia.org/wiki/Date_of_Easter

--
-v
"What did you give up for Lent?" "Religion."

On Tue, 27 Feb 2024 01:28:53 -0000 (UTC), vallor wrote:

> I really wish the function easterg() was commented better.

I’m not really sure that longer symbol names would make anything clearer.
Maths is like that: the important thing is the structure of the formula,
not the names for the quantities in it.

On 26/02/2024 19:20, Joe Pfeiffer wrote:
> Lawrence D'Oliveiro <ldo@nz.invalid> writes:
>
>> On Sat, 24 Feb 2024 21:15:56 -0000 (UTC), Mike Sanders wrote:
>>
>>> Calculate the date of Easter Sunday or Good Friday:
>>
>> Did you know that one of the requirements of the rules was that Easter
>> would never coincide with Passover? Because the sight of Christians
>> celebrating together with Jews was seen as heretical or something ...
>
> That's an Eastern Orthodox rule, not Western. Last year (western)
> Easter was April 9, while Passover was April 5 through 13 (this year
> they don't overlap).

Are you sure it is a rule at all?

In one of the early counsels establishing the "official" doctrine of the
early Christian (Catholic) church, the date system for holy days was
defined as independent of the Hebrew calendar. That meant that the
system for determining the date of Easter was not the same as for the
Jewish Passover, and they did not have to match up. But it /also/ meant
that they could, coincidentally, occur at the same time.

Did the Eastern Orthodox church specifically add this rule afterwards?
I thought the Eastern Orthodox churches used basically the same
algorithm as the Western churches, just with a different calender and (I
think) a slightly different way to define their "lunar" cycles. (I put
"lunar" in quotation marks, since neither Eastern nor Western "lunar"
cycles matches exactly with the moon.)

My knowledge of the details of Eastern Orthodox churches is shaky at
best, so I could be getting this wrong.

On 26/02/2024 18:26, Lew Pitcher wrote:
> On Mon, 26 Feb 2024 11:45:36 +0100, David Brown wrote:
>
>> On 25/02/2024 18:39, Lew Pitcher wrote:
>>> On Sat, 24 Feb 2024 21:15:56 +0000, Mike Sanders wrote:
>>>
>>>> Calculate the date of Easter Sunday or Good Friday:
>>>>
>>>> https://busybox.neocities.org/notes/is-easter-or-goodfriday.txt
>>>
>>> I don't have the expertise to discuss whether or not your code
>>> properly implements the calculations necessary to determine the
>>> date of Good Friday and/or Easter. However, I /do/ have some
>>> expertise on writing understandable code.
>>>
>>> My suggestions, with respect to your program, would be to
> [snip]
>>> b) Don't place your calculations /in/ the object initializations.
>>> Doing so obfuscates the intent of the logic, and makes
>>> problem determination and resolution difficult.
>>
>> I'd disagree with that one. Initialise your variables when you have
>> something to put in them, and that is often a calculated value.
>
> I base my suggestion on the OP's source:
> int isEasterOrGoodFriday(const struct tm *now, int checkGoodFriday) {
>
> int Y = now->tm_year + 1900; // correcting the year
> int a = Y % 19;
> int b = Y / 100;
> int c = Y % 100;
> int d = b / 4;
> int e = b % 4;
> int f = (b + 8) / 25;
> int g = (b - f + 1) / 3;
> int h = (19 * a + b - d - g + 15) % 30;
> int i = c / 4;
> int k = c % 4;
> int L = (32 + 2 * e + 2 * i - h - k) % 7;
> int m = (a + 11 * h + 22 * L) / 451;
> int month = (h + L - 7 * m + 114) / 31;
> int day = ((h + L - 7 * m + 114) % 31) + 1;
>
> if (checkGoodFriday) {
> [rest of code elided]
>
> The program code /depends/ on the specific order of
> the declarations: <<Y>> /must/ be declared before <<a>>,
> <<a>> /must/ be declared before <<h>>, etc.

Yes, because "a" is initialised with an expression using "Y".

>
> If some good-meaning (or unknowledgable) maintainer decides to
> reorder or consolidate the above declarations, the program
> either fails or gives erroneous results.

Why would anyone do that? These are initialised variables that depend
on each other. Re-ordering makes no more sense than re-ordering
printf("world\n") before printf("Hello ").

>
> The OP embedded the /logic/ of the program within the declarations.

You mean, the variables are declared only when there was something to
put in them?

> That, to me. is /not/ good programming.

It has been good programming for many decades in C - it doesn't even
need C99.

>
> Hope this helps clarify my earlier remarks.

If you are trying to say that you think the "correct" way to write C
code is to declare all your variables without initialisation at the
start of the function and have a strict separation from the expressions
and statements of the function, then I know what you are saying. I
totally disagree with it, but that is a discussion that comes up
regularly, and I believe we've been through it recently. It would be
on-topic in c.l.c., which is nice, but I'm not sure we'll cover anything
new.

If that's /not/ what you are saying, them I'm afraid I don't yet
understand your point.

On 2/26/24 18:20, Lawrence D'Oliveiro wrote:
> On Mon, 26 Feb 2024 11:24:29 -0700, Joe Pfeiffer wrote:
>
>> Lawrence D'Oliveiro <ldo@nz.invalid> writes:
>>
>>> Easter, Christmas ... both ancient pagan festivals co-opted by the
>>> Christians and given an invented meaning under their ideology, for
>>> their own propaganda purposes.
>>
>> While that unquestionably true of Christmas, Easter very clearly comes
>> from Passover.
>
> Easter bunny? Eggs? Both fertility symbols, associated with (northern)
> spring and the beginning of the planting season? And both with origins
> older than Christianity and Judaism combined?
>
> Somehow I doubt it.

He was not talking about Easter customs, he was talking about the
*definition" of Easter - the date on which it is celebrated, which is
the very Subject of this [OT] thread. The Last Supper is unambiguously
described in the Christian Bible as occurring during the week of
Passover, which starts on Nissan 15 in the Hebrew calendar. As a result,
the early Christians, who merely considered themselves a sect of
Judaism, originally celebrated Easter a few days later, corresponding to
Jesus' supposed resurrection from the dead.

By the Council of Nicaea, some Christians had come to believe that the
Jews were misinterpreting their own rules for the Jewish calendar,
sometimes starting the month of Nissan on the wrong date. They were
chafing against the idea that they had to accept Jews as authorities on
that matter, which is why Council decided otherwise. They were not
co-opting a pagan date - they were trying to be MORE correct than the
Jews as to the timing of Passover.

On Mon, 26 Feb 2024 11:20:14 -0700
Joe Pfeiffer <pfeiffer@cs.nmsu.edu> wrote:

> Lawrence D'Oliveiro <ldo@nz.invalid> writes:
>
> > On Sat, 24 Feb 2024 21:15:56 -0000 (UTC), Mike Sanders wrote:
> >
> >> Calculate the date of Easter Sunday or Good Friday:
> >
> > Did you know that one of the requirements of the rules was that
> > Easter would never coincide with Passover? Because the sight of
> > Christians celebrating together with Jews was seen as heretical or
> > something ...
>
> That's an Eastern Orthodox rule, not Western. Last year (western)
> Easter was April 9, while Passover was April 5 through 13 (this year
> they don't overlap).

This year Western Easter does not overlap with Passover because of
approximately four day difference in definition of official start of
Spring. When there is a full moon between 21st and 24th of Martch, by
Western rules it's already Spring, but by Jewish rules it's still
Winter and does not count.
It happens approximately 3 times in 19-year cycle. Or, may be, exactly
3 times, I don't know for sure.
So, it seems, Western Easter overlaps with Passover in overwhelming
majority of years - 16 out of 19.

On 27.02.2024 00:31, Scott Lurndal wrote:
>
> March was the first month of the year in Roman times (which is why september
> is derived from the latin for seven). [...]

Actually true for September, October, November, and December (derived
from numbers 7, 8, 9, 10 in Latin).

Janis

On 27.02.2024 10:08, David Brown wrote:
> [...] I
> thought the Eastern Orthodox churches used basically the same algorithm
> as the Western churches, [...]

That was the impression I got when skimming through the Wikipedia
articles.[*]

Janis

[*] See chapter "Gültigkeit" on
https://de.wikipedia.org/wiki/Gau%C3%9Fsche_Osterformel
which says that (at least the Gauss') calculation applies to Julian
and Gregorian calendars, and at the end of the next chapter explains
the parameters for Julian calendar and that it can easily be adjusted
for the Gregorian by OS_Ost = OS + (X div 100) − (X div 400) − 2.

On Tue, 27 Feb 2024 13:12:44 +0200
Michael S <already5chosen@yahoo.com> wrote:

> On Mon, 26 Feb 2024 11:20:14 -0700
> Joe Pfeiffer <pfeiffer@cs.nmsu.edu> wrote:
>
> > Lawrence D'Oliveiro <ldo@nz.invalid> writes:
> >
> > > On Sat, 24 Feb 2024 21:15:56 -0000 (UTC), Mike Sanders wrote:
> > >
> > >> Calculate the date of Easter Sunday or Good Friday:
> > >
> > > Did you know that one of the requirements of the rules was that
> > > Easter would never coincide with Passover? Because the sight of
> > > Christians celebrating together with Jews was seen as heretical or
> > > something ...
> >
> > That's an Eastern Orthodox rule, not Western. Last year (western)
> > Easter was April 9, while Passover was April 5 through 13 (this year
> > they don't overlap).
>
> This year Western Easter does not overlap with Passover because of
> approximately four day difference in definition of official start of
> Spring. When there is a full moon between 21st and 24th of Martch, by
> Western rules it's already Spring, but by Jewish rules it's still
> Winter and does not count.
> It happens approximately 3 times in 19-year cycle. Or, may be, exactly
> 3 times, I don't know for sure.
> So, it seems, Western Easter overlaps with Passover in overwhelming
> majority of years - 16 out of 19.
>

P.S.
Eastern Easter, more properly called Pascha, rarely coincides with
Passover week, but not by ideological design, as insinuated by Lawrence
D'Oliveiro. It happens because, due to accumulated errors, Julian
Spring starts ~15 days after solar equinox while Jewish Spring starts
~5 days after solar equinox*.

Despite that, sometimes Pascha does happen during Passover. The next
such time will be in 2028, where Pascha will be in the last day of
Passover. I would think that few centuries ago it happened more often
and 1000 years ago it happened most of the time.

* - it's more complicated, really, but for practical purposes of
calculation of Passover day the above holds.

On Tue, 27 Feb 2024 05:02:58 -0500, James Kuyper wrote:

> They were not co-opting a pagan date - they were trying to be MORE
> correct than the Jews as to the timing of Passover.

Religion is a matter of belief, not fact. Trying to be “more correct” than
official religious authorities has a name: “heresy”.