# Re: [whatwg] for year input

```Nils Dagsson Moskopp writes:

> Jonathan Watt <jw...@jwatt.org> writes:
>
> > is it wrong to use <input type=number> for year input.
>
> I am certainly not an expert on the topic, but I believe the
> conceptual problem can be reduced to using an input designed for a
> group (in the mathematical sensce) to represent a value that is
> torsor.
>
> Quote <http://ro-che.info/articles/2013-01-08-torsors.html>:```
```
That seems to be begging the question.

What is it about <input type=number> that leads you to believe it makes
sense to add two such values together?

Would you also rule out <input type=number> for page numbers — if I've
reached page 122 of a book and you've read up to page 169, adding those
together to get page 291 doesn't make any sense, especially if the book
only has 255 pages.

Or for temperatures in a degree scale, such as Celsius? Here in Leeds it
was 10°C yesterday and is 13°C today, but adding those together to make
23° is absurd.

Or what about for people's ages? It seems nonsense to me when the media
write things like The Rolling Stones having “a combined age of 273”, yet
they do:
http://www.standard.co.uk/goingout/music/the-rolling-stones-o2-arena--review-8351840.html

> > While adding two dates is not possible, it is possible to add a time
> > interval to a date («five days from today»). This suggests that we
> > should not confound dates and time intervals — they are different
> > types of values.
>
> Therefore asking for a duration using <input type=number> is fine –
> asking for a calendar year, however, is obviously a type error.
>
> <http://math.ucr.edu/home/baez/torsors.html>

That doesn't seem obvious to me at all. The only mathematical operations
I've seen available on <input type=number> are increment and decrement,
which clearly is possible on (Gregorian) years.

There are many situations where a web form could wish to collect a
non-self-addable value such as a temperature. What would be the
advantage in telling web authors they can't use <input type=number> for
these?

We could add <input type=torsor> (except I suspect most web authors
would be unfamiliar with the term; I can't find it in the ‘Oxford
English Dictionary’), but if it's appearance, interface, and behaviour
are identical to that of <input type=number>, what is the point of
distinguishing the two?

Cheers

Smylers
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