See: http://lea.verou.me/2014/07/an-easy-notation-for-grayscale-colors/ & vote! (ideally, with justification)
Done. I voted for extending
rgb(a). The explicit ones,
black are all ambiguous names (why does
white(0) result in black?) Other methods could be defined, yes, but looking at how well the
#123 short form of
#112233 works, a shortcut for
rgb(a) seems the perfect way to go.
Bit off-topic, but somehow relevant: A nice advantage of overloading
would then be easier to spec, too.
That’s handled by the specced
color() function, like