Media descriptors in (X)HTML are currently defined as a comma-separated list. However, this is inconsistent with other list attributes in (X)HTML, such as @class, @rel (such as in links) and others. @media is defined as comma-separated in order to stay consistent with CSS, which was the origin of the attribute. However, this renders it strange to (X)HTML developers. This should be fixed by making @media space-separated. Note that constructs such as "print and resolution > 90dpi" can easily be converted to "print[resolution>90dpi]", which has the same effect but is consistent with other (X)HTML attributes.
What is the problem you are trying to solve?
I am trying to make (X)HTML more consistent and thus easier to write for developers.
What is the feature you are suggesting to help solve it?
A small change to the @media attribute (such as of <link>s and <style>s) that would make it space, not comma, separated.
What is the processing model for that feature, including error handling?
This would function in the same way as other attributes. Its a small change and should not mean any significant change to the processing model.
Why do you think browsers would implement this feature?
Many browsers already recognize space-separated lists for the @media attribute.
Why do you think authors would use this feature?
This section doesn't really apply to my proposal.
What evidence is there that this feature is desparately needed?
I myself have often made mistakes based on this inconistency. It is easy to imagine that while this doesn't necessarily cause mistakes often, its a pain to remember and an annoying inconsistency.