Re: [whatwg] Week Strings
Ian Hickson writes: On Fri, 19 Jun 2009, Smylers wrote: For input type=week elements the spec requires: The value attribute, if specified, must have a value that is a valid week string. -- http://www.whatwg.org/html5#week-state But the spec's HTML source contains this comment immediately afterwards: !-- ok to set out-of-range value, we never know when we might have to represent bogus input -- it [...] means that there's no requirement that the value= be within the range given by min= and max=. Thanks for clarifying that. input type=week value=2010-W53 input type=week value=2010-W54 If out-of-range week values are to be permitted in input elements then a validator should permit both of them. Conversely if they aren't permitted then it should accept neither of them. Please report such bugs straight to Henri. :-) Of course -- but I wanted to check what the correct behaviour was first. Smylers
Re: [whatwg] Week Strings
On Fri, 19 Jun 2009, Smylers wrote: For input type=week elements the spec requires: The value attribute, if specified, must have a value that is a valid week string. -- http://www.whatwg.org/html5#week-state But the spec's HTML source contains this comment immediately afterwards: !-- ok to set out-of-range value, we never know when we might have to represent bogus input -- Does that comment mean that the above requirement will be changed to something along the lines of must have a value that is a syntactically valid week string but may represent a week that doesn't actually exist? No, it just means that there's no requirement that the value= be within the range given by min= and max=. It's a reminder to myself in case I notice there's no such requirement one day and go and add one thinking it was a mistake. That is, the author can seed a browser's week-picker control to a value which the browser must not submit back to the server? So long as it is a valid week string, yes. In general determining that something is a valid week string requires knowing which day of the week the year in question begins on. For example 2009-W53 is a valid week string (because 2009 began on a Thursday) but 2010-W53 isn't (because 2010 will begin on a Friday). Browsers will need to do this to know whether they can submit a week value. Yup. The spec doesn't appear to provide an algorithm for determining which day of the week a year begins on (however I am not a browser developer; possibly this is sufficiently straightforward that those who are don't need it spelling out). As far as I can tell, it is well-defined in the spec. Currently Validator.nu accepts this: input type=week value=2010-W53 but not this: input type=week value=2010-W54 If out-of-range week values are to be permitted in input elements then a validator should permit both of them. Conversely if they aren't permitted then it should accept neither of them (and therefore have to implement a 'which day is January 1st' algorithm, which I'm guessing it currently doesn't). Please report such bugs straight to Henri. :-) -- Ian Hickson U+1047E)\._.,--,'``.fL http://ln.hixie.ch/ U+263A/, _.. \ _\ ;`._ ,. Things that are impossible just take longer. `._.-(,_..'--(,_..'`-.;.'
Re: [whatwg] Week Strings
On Fri, 19 Jun 2009, 'Smylers' wrote: And even states the blindingly obvious: The 'week number of the last day' of a week-year with 53 weeks is 53; the 'week number of the last day' of a week-year with 52 weeks is 52. I use the term week number of the last day as a kind of function in the spec, so while it may be obvious, it has to be listed explicitly otherwise one could argue that it isn't defined. (I could probably just stop using it as a function and just assume that people will apply common sense, but sometimes that doesn't work so well...) -- Ian Hickson U+1047E)\._.,--,'``.fL http://ln.hixie.ch/ U+263A/, _.. \ _\ ;`._ ,. Things that are impossible just take longer. `._.-(,_..'--(,_..'`-.;.'
[whatwg] Week Strings
For input type=week elements the spec requires: The value attribute, if specified, must have a value that is a valid week string. -- http://www.whatwg.org/html5#week-state But the spec's HTML source contains this comment immediately afterwards: !-- ok to set out-of-range value, we never know when we might have to represent bogus input -- Does that comment mean that the above requirement will be changed to something along the lines of must have a value that is a syntactically valid week string but may represent a week that doesn't actually exist? That is, the author can seed a browser's week-picker control to a value which the browser must not submit back to the server? In general determining that something is a valid week string requires knowing which day of the week the year in question begins on. For example 2009-W53 is a valid week string (because 2009 began on a Thursday) but 2010-W53 isn't (because 2010 will begin on a Friday). Browsers will need to do this to know whether they can submit a week value. The spec doesn't appear to provide an algorithm for determining which day of the week a year begins on (however I am not a browser developer; possibly this is sufficiently straightforward that those who are don't need it spelling out). Currently Validator.nu accepts this: input type=week value=2010-W53 but not this: input type=week value=2010-W54 If out-of-range week values are to be permitted in input elements then a validator should permit both of them. Conversely if they aren't permitted then it should accept neither of them (and therefore have to implement a 'which day is January 1st' algorithm, which I'm guessing it currently doesn't). Smylers
Re: [whatwg] Week Strings
On Fri, 19 Jun 2009 11:48:17 +0200, Smylers smyl...@stripey.com wrote: The spec doesn't appear to provide an algorithm for determining which day of the week a year begins on (however I am not a browser developer; possibly this is sufficiently straightforward that those who are don't need it spelling out). It does actually, but it is not clearly linked from valid week and such: http://www.whatwg.org/specs/web-apps/current-work/#weeks If out-of-range week values are to be permitted in input elements then a validator should permit both of them. Conversely if they aren't permitted then it should accept neither of them (and therefore have to implement a 'which day is January 1st' algorithm, which I'm guessing it currently doesn't). Or maybe it implements the bogus one the specification previously defined. -- Anne van Kesteren http://annevankesteren.nl/
Re: [whatwg] Week Strings
Anne van Kesteren writes: On Fri, 19 Jun 2009 11:48:17 +0200, Smylers smyl...@stripey.com wrote: The spec doesn't appear to provide an algorithm for determining which day of the week a year begins on (however I am not a browser developer; possibly this is sufficiently straightforward that those who are don't need it spelling out). It does actually, but it is not clearly linked from valid week and such: http://www.whatwg.org/specs/web-apps/current-work/#weeks That says that 1969 December 29th was a Monday, but doesn't appear to give an algorithm for answering the question Will the year 2010 begin on a Thursday?. Smylers
Re: [whatwg] Week Strings
An algorithm for calculating the weekday of Jan. 1st given a year would be outside the scope of the HTML specification. Similarly, the HTML specification does not describe how you increment a number by 1. IMHO, Chris
Re: [whatwg] Week Strings
Křištof Želechovski writes: An algorithm for calculating the weekday of Jan. 1st given a year would be outside the scope of the HTML specification. That's begging the question. Similarly, the HTML specification does not describe how you increment a number by 1. No, but it does explain how to interpret a sequence of digits as an integer (multiplying the value by 10 for each digit encountered). And defines that week is a period of 7 days. And defines how many days there are in each month of a year. And even states the blindingly obvious: The 'week number of the last day' of a week-year with 53 weeks is 53; the 'week number of the last day' of a week-year with 52 weeks is 52. Those things all seem much more obvious to me than working out which day January 1st of a given year is. But as I said, I'm not a browser developer so perhaps it's fine. Smylers
Re: [whatwg] Week Strings
On Fri, Jun 19, 2009 at 2:32 PM, Smylerssmyl...@stripey.com wrote: The 'week number of the last day' of a week-year with 53 weeks is 53; the 'week number of the last day' of a week-year with 52 weeks is 52. well... there are people who might think you could count from week 0 if weeks are numbered from the first whole week. there are all sorts of ways to get numbering wrong. (I've been at a place which has both 53 and 0 ...)
Re: [whatwg] Week Strings
An algorithm to calculate the weekday of Jan. 1th given a year is not obvious at all. Just the opposite: the more obvious an external fact is, the easier (and more appropriate) it is to incorporate it to the specification because it does not cause any distraction from the main subject. Cheers, Chris
Re: [whatwg] Week Strings
timeless writes: On Fri, Jun 19, 2009 at 2:32 PM, Smylerssmyl...@stripey.com wrote: The 'week number of the last day' of a week-year with 53 weeks is 53; the 'week number of the last day' of a week-year with 52 weeks is 52. well... there are people who might think you could count from week 0 Except that the spec has already defined that a year starts on week 1 before the above sentence. Smylers
Re: [whatwg] Week Strings
Getting the day of the week, in the Gregorian calendar, for a given date is pretty straightforward. I thought we publihsed it online somehwere on the Royal Observatory website, but I can't find it. However, wikipedia has the algorithm: http://en.wikipedia.org/wiki/Calculating_the_day_of_the_week#An_algorithm_to _calculate_the_day_of_the_week Cheers Jim O'Donnell Original Message: - From: K�i�tof �elechovski giecr...@stegny.2a.pl Date: Fri, 19 Jun 2009 13:39:55 +0200 To: smyl...@stripey.com, whatwg@lists.whatwg.org Subject: Re: [whatwg] Week Strings An algorithm to calculate the weekday of Jan.�1th given a year is not obvious at all. Just the opposite: the more obvious an external fact is, the easier (and more appropriate) it is to incorporate it to the specification because it does not cause any distraction from the main subject. Cheers, Chris mail2web LIVE Free email based on Microsoft® Exchange technology - http://link.mail2web.com/LIVE
