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Common Calendrical Fallacies

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Re: Common Calendrical Fallacies

#41

Post by charcircuit »

cutler wrote: post #37
charcircuit wrote: post #34

Earlier quoted context omitted.

I don't really care about what causes it. The exact start and end dates of the seasons don't really matter, nor do they need to be consistent. Each season has things associated with them like fall has leafs turning orange and falling, or snow in winter.

Well now you're defining seasons in terms of weather and we all know how reliable that is. Here in London we've had zero snow this winter so far so does that mean we haven't had a winter? There are plenty of countries, especially the ones close to the equator, who have never experienced snow and whose summers and winters are barely distinguishable in terms of temperature yet they still have a summer and a winter defi…

>Here in London we've had zero snow this winter so far so does that mean we haven't had a winter?

If it didn't get colder than fall than it would be possible to skip winter.

Re: Common Calendrical Fallacies

#42

Post by ksaj »

This is like the problem with astrology, since there are actually 13 sidereal months. You can even see that in the charts that show the star and planet locations on any given day, but somehow they are ignored by "psychics" everywhere.

Re: Common Calendrical Fallacies

#43

Post by cutler »

charcircuit wrote: post #41
cutler wrote: post #37

Earlier quoted context omitted.

Well now you're defining seasons in terms of weather and we all know how reliable that is. Here in London we've had zero snow this winter so far so does that mean we haven't had a winter? There are plenty of countries, especially the ones close to the equator, who have never experienced snow and whose summers and winters are barely distinguishable in terms of temperature yet they still have a summer and a winter defi…

>Here in London we've had zero snow this winter so far so does that mean we haven't had a winter? If it didn't get colder than fall than it would be possible to skip winter.

So seasons are defined by temperature? In the UK we sometimes have our coldest weather in March. Does that mean the seasons have shifted? And what about countries close to the equator - do they have permanent summer? Seasons have nothing to do with temperature. Global warming is set to make that even more apparent.

Re: Common Calendrical Fallacies

#44

Post by tdeck »

dahfizz wrote: post #3

This comes off as very "well akchtually"; more snarky than helpful. A great example: >It is normal that the Sept-, Oct-, Nov-, and Dec- months are numbered 9, 10, 11, and 12 >False. This is very weird. They used to be months 7, 8, 9, and 10, but some reform to the Roman calendar back in the day resulted in the creation of January and February, which messed everything up. No software project cares what the calendar lo…

While we're at it, I'm surprised there's no mention that the new year started in March for English speakers into the late 18th century:

https://en.m.wikipedia.org/wiki/Old_Style_and_New_Style_date...

Re: Common Calendrical Fallacies

#45

Post by charcircuit »

cutler wrote: post #43
charcircuit wrote: post #41

Earlier quoted context omitted.

>Here in London we've had zero snow this winter so far so does that mean we haven't had a winter? If it didn't get colder than fall than it would be possible to skip winter.

So seasons are defined by temperature? In the UK we sometimes have our coldest weather in March. Does that mean the seasons have shifted? And what about countries close to the equator - do they have permanent summer? Seasons have nothing to do with temperature. Global warming is set to make that even more apparent.

>So seasons are defined by temperature?

In part. I'd say it's a combination of the temperature and amount of light you get per day.

Re: Common Calendrical Fallacies

#46

Post by alexdbird »

I was relieved to read the final paragraph.

I have found NSDate/NSCalendar to be the best designed API for date and time calculations, and I never knew it was built on top of ICU. It discourages bad assumptions while many others try to make a more 'fluent' interface that encourages them.

When I first tried Joda in Java it had a builder interface that stank, I was able to easily write tests that produced the wrong date or threw an exception simply by changing the order of construction. But I think that's long gone.

Re: Common Calendrical Fallacies

#47

Post by _vdpp »

cutler wrote: post #36
dahfizz wrote: post #35

Earlier quoted context omitted.

The entire concept of a "season" is invented. Quantizing a continuous natural phenomena into descreet bits is something humans do with everything, and we nearly never do it rigorously. When is it "night"? At what exact moment in time does it become "night"? Nobody knows, nobody cares. It's still a useful concept.

Night is clearly defined by the Sun setting over the horizon and the following rising. The Sun's passage over the meridian is the astronomical midnight.

It’s not always clear. For instance pilots can log night hours once it’s civil twilight, but there’s also nautical twilight and then astronomical twilight, all defined by the number of degrees below the horizon the sun is. What we consider “night” is pretty arbitrary.

Re: Common Calendrical Fallacies

#48

Post by atoav »

nulbyte wrote: post #9
atoav wrote: post #2

Some of these are quite interesting, e.g. that Oceania has an offset from ITC >12 hours. Others are coming of more like pedantic "gotcha" questions where the answer is that some more or less obscure calendar system is the exception here. Yeah sure it is, why wouldn't the year in the japanese calendar depend on the death of their emperor. That just isn't something my small software tool is likely willing to support an…

> So I think instead of "scolding" the reader with a False here, maybe a Depends would be both more friendly and more well suited. I like this. False suggests it is objectively false, but you're right, it really depends on more information. And it's important that people working with dates and times understand that they need more information.

At least they need enough i formation to realize they don't wanna handle this entirely by themselves.

The point however is that every dev sometimes needs to make assumptions about an calendar — even those who are smart enough not to write their own calendar. E.g. if you think about a typical fitness tracker of course the devs will have to make assumptions about weeks and months, instead of supprting every calendar under the sun.

This is why a Depends makes a lot more sense here: Knowing that it exists is good, but you might not have to support it in an 1.0 release

Re: Common Calendrical Fallacies

#49

Post by berkes »

dahfizz wrote: post #3

This comes off as very "well akchtually"; more snarky than helpful. A great example: >It is normal that the Sept-, Oct-, Nov-, and Dec- months are numbered 9, 10, 11, and 12 >False. This is very weird. They used to be months 7, 8, 9, and 10, but some reform to the Roman calendar back in the day resulted in the creation of January and February, which messed everything up. No software project cares what the calendar lo…

> Obviously, anyone who says "the current year is 2020" is talking about the Gregorian calendar that everyone is familiar with

Context always matters.

Which is why we have (or should have) Domain Boundaries. Within which we have (or should have) ubiquitous language. And within wich our deliberate assumptions always hold true.

More practical, this is one reason why you want to isolate dependencies behind an anti-corruption layer, or some adapters or whatever architecture to isolate. It isolates your internal context, where it is fine to assume 2020 is western calendar and not the Thai calendar (where the current year is 2565, and used by some hundred million potential customers). Eventhough the library you use may deal with all those intricacies, within your domain, you deliberately don't.

These problems are solved. Eric Evans wrote a fantastic book (DDD) explaining how it has been solved, 18 years ago. We must keep bringing such problems up. But we should try to avoid inventing solutions again and again.

And we should certainly avoid giving up, and saying this silly, unsolvable or Just Too Hard™.

Re: Common Calendrical Fallacies

#50

Post by cutler »

charcircuit wrote: post #45
cutler wrote: post #43

Earlier quoted context omitted.

So seasons are defined by temperature? In the UK we sometimes have our coldest weather in March. Does that mean the seasons have shifted? And what about countries close to the equator - do they have permanent summer? Seasons have nothing to do with temperature. Global warming is set to make that even more apparent.

>So seasons are defined by temperature? In part. I'd say it's a combination of the temperature and amount of light you get per day.

The summer solstice around 20th June will always be mid-summer in the northern hemisphere even if it's freezing cold for the 45 days before and after. It's all about daylight and darkness. Nothing else.
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