You're filling a personal injury insurance claim: When did injury start? is easy, but what if you're still getting treatment? What do you put in the finish date box? D/a/y lets you put 'not yet' which is the only accurate answer. (And D/a/y also knows how to do calculations using that value.)
When did you have a particular vaccination? How are you with YY/MM/DD for 30-ish years ago? Depending on the application a guessed year or Not-known or A long time ago might be appropriate.
Your project is delayed a month so how do you add one month to Jan 31st? (2015 or 2016) D/a/y has a clear specification for the slippery and elastic matter of months.
17th September is a real world date, your birthday perhaps. Talking of birthdays, when is the new baby due?
|Year, month and day or year and month or just a year|
|We simply don't know. (Not the same thing as)|
|We've found some logical error. (Not the same thing as)|
|We don't have data going back beyond a certain point|
|Ongoing. A very common pattern in real-world applications|
|A month or a month and a day. Start of tax years for example|
|Numeric values of days, months and years used when comparing or shifting days|
|Something went wrong with calculations|
years months and days. Using Day you'll do something like|
var age = dToday.Difference(dBorn); then age.ToString() for + 44y 6m 12d
|How old are you?||Today - 1960||Oh dear! 1960 is a real-world date but we've got two problems.|
(2) Then it gives us a result with false (day) precision.
Day would subtract 1960 from 2015 say and report that it had an answer only accurate to years.
|How long since you left school?||Today - June 1978||Clearly without a day we're only able to calculate to monthly precision. That's no problem for Day|
|How long since the battle of Hastings?||Today - 1066||Similar problem. Day will tell us 949 years|
|How long was/is your arm in plaster?||Today - 12 June 2015||The 'Today' value is a very common input. In this case we can do a simple sum with 'Today' meaning 'so far'.|
|What is 31st January 2015 plus one month?||Shennanigans!||28 Feb 2015|
|What is 28th January 2015 plus one month?||Shennanigans!||27 Feb 2015|
|When is the end of the tax year?||4th April||No year! We call this a floating date. Happy birthday!|
|What about internationalisation?||Easy to edit dictionaries are part of the Day architecture|
|What are limits?||4095 BC to 4095 AD|
|Is it tested?||There's a test suite available for download.|
|Is it free?||Yes|
|Is it available?||Probably late summer 2015|