Re: [mediaqueries4]Differentiating touchscreen+mouse from touchscreen only scenarios

> >I think a less error-prone approach to separating them is to have 
> >separate boolean rules, eg. 'fine-pointer' and >'coarse-pointer'.  This 
> >is >also more extensible (eg. what if we decide there's another option 
> >than just coarse >and fine, 'both' would be pretty confusing <grin>).
> You make a good point and I can both agree with it and align with this.

Fwiw, I think this could possibly be a mistake; it looks like a 
reincarnation of the problem Pointer Events tried to solve, put another way.



Wouldn't it be better to have

    primary-pointer: (fine || coarse) && (has-hover || has-no-hover)
    any-pointer: (fine || coarse || fine && coarse) && (has-hover || 
has-no-hover || has-hover && has-no-hover)

    - where "primary-pointer" returns the value of the most convenient input 
method (and opposite values are therefore mutually exclusive),
    - and where "any-poiner" returns the combination of the flags that match 
any of the enabled input methods without distinction.

?



That way, we can detect "touch support on laptops" or "digital pen input on 
tablets" using "any-pointer" while still keeping the site-optimization task 
simple using "primary-pointer".



Exposing both properties enables more complex scenarii like making "enable 
touch interface" button visible when "@media(any-pointer: coarse)" but 
enable the coarse mode only when either "this button is toggled on" or 
"@media(primary-pointer: coarse)". Once browsers support Custom CSS At-Rule, 
this could be as easy as "@media(--ui-mode: coarse)" with a simple JS 
maintaining the state accordingly by listening to the related events (while 
we wait we could use a css class on the root element).