[csswg-drafts] [css-values] Define <positive-integer>, <positive-number>, <positive-length>, etc. sub-types

AmeliaBR has just created a new issue for 
https://github.com/w3c/csswg-drafts:

== [css-values] Define <positive-integer>, <positive-number>, 
<positive-length>, etc. sub-types ==
Many properties only accept positive values.  Negative values are 
illegal, and are parse errors.  This is currently only defined in 
prose for the relevant property.  Examples: width, height, 
line-height.

In contrast, other properties have logical bounds, but values outside 
these bounds are parsed as normal and only clamped at used value time.
 Examples: opacity, numeric parameters in color functions.

I'm sure it would be useful for both authors and implementers if the 
property value syntax explicitly indicated whether negative values 
would be a parse error or not.  That requires new value types in [CSS 
Values & Units](https://drafts.csswg.org/css-values/).

I'm not sure if there are any other common "illegal value" 
restrictions currently defined in prose, but it's worth looking around
 to see if there are, and if they can also be standardized into the 
value definition syntax.


Please view or discuss this issue at 
https://github.com/w3c/csswg-drafts/issues/355 using your GitHub 
account

Received on Thursday, 28 July 2016 17:22:13 UTC