Re: Which DOW is day #1?
On Fri, 24 Jan 2003, Peter J. Acklam wrote: I believe this thread proves that what is considered the first day of the week must be customizable. If it isn't, then someone (perhaps not someone on this mailing list, but someone) will be dissatisfied and consider the DateTime modules useless and write their own modules -- and much of the point with the DateTime modules will be lost. As Rich pointed out, the idea of offering a rich API that supports all of these things is good. The idea of a narrow API which has a changing meaning is very bad. We already have some of the rich API needed, like day_of_week and day_of_week_0. In relation to week numbers and day of week numbers, there are at least four parameters that must be customizable: 1) What is the first day of a week (Sunday, Monday, ...)? I just need method names for this. Monday as first day of week is day_of_week (Monday is 1) and day_of_week_0 (Monday is 0). Equivalent methods using Sunday are welcome, but they need good names. 2) What is the number of this day (0, 1)? See above. 3) How many days of a week must be in the new year before the week is considered the first week in the new year? (ISO: 4, US: 1 and 7) Eek, I'm not sure I want to touch this yet. But if people have good mehod names, I'm happy to include it. 4) What is the number of this week (0, 1)? This can be done with more *_0 methods. This all comes down to have appropriately named methods, basically. -dave /*=== House Absolute Consulting www.houseabsolute.com ===*/
Re: Which DOW is day #1?
On Fri, 24 Jan 2003, Dave Rolsky wrote: On Fri, 24 Jan 2003, Peter J. Acklam wrote: In relation to week numbers and day of week numbers, there are at least four parameters that must be customizable: 1) What is the first day of a week (Sunday, Monday, ...)? I just need method names for this. Monday as first day of week is day_of_week (Monday is 1) and day_of_week_0 (Monday is 0). Equivalent methods using Sunday are welcome, but they need good names. So if I want to use Sunday as the first day of the week every will method I use will have sunday in it? What if for some business reason I decide that it's easier to do my calculations if Wednesday is the first day of the week? How about: use DateTime; use DateTime::Lingua::EN; use DateTime::Lingua::FR; DateTime::first_day_of_week( DateTime::Lingua::EN::SUNDAY ); or maybe we can make english the blessed default language like we are doing for the Gragorian Calendar DateTime::first_day_of_week( SUNDAY ); # Exported Constant? DateTime::first_day_of_week( DateTime::Lingua::EN::DIMANCHE ); And then use the '_0' methods as desired if you want a 0 based index I'd prefer the above plus $d-weekday_num_0 over $d-weekday_num_sunday_0; $d-weekday_num_wednesday_0; 3) How many days of a week must be in the new year before the week is considered the first week in the new year? (ISO: 4, US: 1 and 7) Eek, I'm not sure I want to touch this yet. But if people have good mehod names, I'm happy to include it. DateTime::min_days_first_week_of_year(7) If it's a Class value and is object overridable ... Clayton
Re: Which DOW is day #1?
On Fri, 24 Jan 2003, Clayton L. Scott wrote:
So if I want to use Sunday as the first day of the week every will
method I use will have sunday in it? What if for some business reason
I decide that it's easier to do my calculations if Wednesday is the first
day of the week?
How about:
use DateTime;
use DateTime::Lingua::EN;
use DateTime::Lingua::FR;
DateTime::first_day_of_week( DateTime::Lingua::EN::SUNDAY );
or maybe we can make english the blessed default language like we are
doing for the Gragorian Calendar
DateTime::first_day_of_week( SUNDAY ); # Exported Constant?
DateTime::first_day_of_week( DateTime::Lingua::EN::DIMANCHE );
This is not going to happen. Allowing this sort of thing makes it
impossible for a module to trust a DateTime object that it's given. The
API needs to be fixed, so that day_of_week _always_ means the same thing.
And if you _really_ want to treat Wednesday as day 1, you can do this.
sub day_of_week_wednesday_first
{
my $dt = shift;
my $dow = $dt-day_of_week; # monday first
$dow = ( ( $dow + 7 ) - 2 ) % 7 );
return $dow;
}
3) How many days of a week must be in the new year before
the week is considered the first week in the new year?
(ISO: 4, US: 1 and 7)
Eek, I'm not sure I want to touch this yet. But if people have good mehod
names, I'm happy to include it.
DateTime::min_days_first_week_of_year(7)
If it's a Class value and is object overridable ...
Again, for the same reasoning as above, this is not going to happen.
Module authors need to be able to say given a DateTime object,
function/method X returns Y, without having to set class variables of its
own (and then who wins?)
-dave
/*===
House Absolute Consulting
www.houseabsolute.com
===*/
Re: Which DOW is day #1?
Dave Rolsky wrote: [...] Make that: $month[ $date-month_0 ] vs. $date-month_name $date-month returns a 1-based numbers $date-month_0 a 0-based named $date-month_name returns a name based on the DateTime::Language module the $date object is holding onto. While I like returning 1 based numbers by default, I'd like to suggest eliminating the _ for the 0 based returns: $date-month0 instead of $date-month_0. Just preference... brad
Re: Which DOW is day #1?
On Sun, 12 Jan 2003, Nick Tonkin wrote: You completely misunderstood my point, Rich. I was not implying any slight whatsoever. I continue to disagree with your opinion about the first day of the week in the Christian tenet(s), about which I know a good deal more than you evidently think. I apologize for taking offence where there was none. I suppose that I am now utterly confused as to in what way you disagree with me. In the Christian week, if we are to call it that, Sunday is the first day of the week, and traditional Christianity recognizes that the Sabbath, which is Saturday, is the seventh day, on which God rested. Which part of that do you feel that I have wrong? But my point was simply that cultural and religious traditions that may not make sense to the programmer are often very important. Similar to what you stated above. OK, true. Since our job is to provide an interface that regular people can understand, and not have to add and subtract to make sense of it. Like adding 1900 to years. :-) -- Rich Bowen - [EMAIL PROTECTED] http://kenya.rcbowen.com/
Re: Which DOW is day #1?
On Sun, Jan 12, 2003 at 09:13:07AM -0500, John Peacock wrote: Dave Rolsky wrote: I'm inclined to go with ISO rather than backwards compatibility with C. We really have to go with ISO because that battle has already been fought and won(?) in the international community. And we have already committed to ignore localtime's perversions when required... iCalendar (rfc 2445) specifies a WKST property for recurrence rules to let you define your own start of the (work) week. The default for this is Monday. Martijn
Re: Which DOW is day #1?
On Sunday, January 12, 2003, at 11:15 AM, John Peacock wrote: A lot of the 0-based vs 1-based arguments should be resolved simply by having our interface design in place. Programmers will be less inclined to have to look up some 0-based array when the API we provide does it for them, i.e. month[$date-month_num] vs. $date-month both return January I think that this will be resolved by: month[$date-month_0] vs. $date-month both return January David -- David Wheeler AIM: dwTheory [EMAIL PROTECTED] ICQ: 15726394 http://david.wheeler.net/ Yahoo!: dew7e Jabber: [EMAIL PROTECTED]
Re: Which DOW is day #1?
On Sunday, January 12, 2003, at 10:48 AM, Rich Bowen wrote: On Sun, 12 Jan 2003, John Peacock wrote: We really have to go with ISO because that battle has already been fought and won(?) in the international community. Well, I was going to say the following: This is not about either ISO standard or backward compatibility with C, but about common usage. People think of Sunday as the first day, and so we should stick with that, so as not to confuse people. However, based on your comment, I'm not sure if that is the case. This is a classic localization problem, with the convention varying from one place and time to another. I've seen a number of indications that many, perhaps most, Europeans consider the week to start on Monday, and a quick Google search turned up more anecdotal support for this theory, ex: Many British calendars and diaries use Monday as the start of the week; but some still use Sunday. (http://www.merlyn.demon.co.uk/weekinfo.htm) Another source clarifies that starting on Sunday is in fact the original pattern, and that counting from Monday is a later development of European cultures, especially Protestant and German-speaking ones. (http://www.friesian.com/week.htm) Personally, I've always preferred calendar weeks that start on Monday, partly for the onomatopoeia (mONEday, TWOsday, 3ednesday, FOURsday, FrIVEsday, ...), and partly because it synched up with the school-day/work-day cycle. Synchronization to the work week is also useful in some kinds of business contexts -- if you're scheduling weekday shifts, it's more convenient for your work days to run from 1-5 than from 2-6 -- and I believe the ISO week-numbering work is based on existing practices in the manufacturing industry. Some desktop calendar software allows you to switch the display to Monday weeks, and many business-week planning calendars also start on Monday. In a sense, one would like to be able to treat this as a locale issue, so that a user could specify the convention used in their setting, in the same way that they can select the language used. (I'm in Germany, give me German day names and ISO weeks.) A simpler solution would be to support multiple interfaces: ($year, $week_num, $week_day) = $dt-greg_week(); ($year, $week_num, $week_day) = $dt-iso_week(); Callers could choose to request whichever number they wanted: - $dt-iso_week_day - 1..7 starting with Monday - $dt-iso_week_day_0 - 0..6 starting with Monday - $dt-greg_week_day - 1..7 starting with Sunday - $dt-greg_week_day_0- 0..6 starting with Sunday -Simon
Re: Which DOW is day #1?
On Sun, 12 Jan 2003, David Wheeler wrote: On Sunday, January 12, 2003, at 11:15 AM, John Peacock wrote: A lot of the 0-based vs 1-based arguments should be resolved simply by having our interface design in place. Programmers will be less inclined to have to look up some 0-based array when the API we provide does it for them, i.e. month[$date-month_num] vs. $date-month both return January I think that this will be resolved by: month[$date-month_0] vs. $date-month both return January Make that: $month[ $date-month_0 ] vs. $date-month_name $date-month returns a 1-based numbers $date-month_0 a 0-based named $date-month_name returns a name based on the DateTime::Language module the $date object is holding onto. -dave /*=== House Absolute Consulting www.houseabsolute.com ===*/
Re: Which DOW is day #1?
On Sun, 12 Jan 2003, Rich Bowen wrote:
On Sun, 12 Jan 2003, Nick Tonkin wrote:
Funny how the Christian point of view is that Sunday is the first day of
the week, when God rested on the seventh day after working to make the
world. Seventh which is Sunday for Christians .. (and Saturday which is
seventh for Jews, so for them Sunday _is_ the first day).
I would greatly prefer it if we not indulge in implied or actual
criticizm of various religions, if it's all the same to you. Your
comments here show that you're unaware of the Christian point of view,
which makes a very clear distinction between the seventh day, on which
God rested, and Sunday, which is a celebration of the resurrection of
Jesus. The seventh day, the Sabbath, is Saturday in the Jewish
tradition. Sunday has been celebrated in the Christian church,
since the first Century AD, in commeration of the resurrection,
not as equated to the Sabbath. That confusion may exist in certain
protestant denominations, but is not the understanding of the larger
Christian Church.
Really the only reason for making this clarification at all, and not
entirely dropping the religious pursuit of this discussion, is that
religion is critical in many of the most interesting calendars on this
planet, and one cannot fully appreciate the history and nuances of any
of these calendars, notwithstanding the ISO, without a correct
understanding of the religious communities that stand behind them, even
if you view them merely as historical curiosities, rather than as
transcendent truths.
So, I, for one, and I'm sure many others, would appreciate it if
everyone restrain from slights, implied or actual, on religions that
will, of necessity, arise in calendrical discussion.
Thanks.
Rich
You completely misunderstood my point, Rich. I was not implying any slight
whatsoever. I continue to disagree with your opinion about the first day
of the week in the Christian tenet(s), about which I know a good deal more
than you evidently think. But my point was simply that cultural and
religious traditions that may not make sense to the programmer are often
very important. Similar to what you stated above. You took offense where
one was neither intended nor made.
- nick
Nick Tonkin {|8^)
