[css, i18n] margin-start, etc.

As far as I understand properties like margin-start, margin-before,
etc. did not go through for many good reasons.
What about something like below then?

New property 'map' that accepts values:
  :  ( mirror-x | mirror-y | rotate-cw | ...)  || margin || padding ||
border || background-position || background-image || all || etc.

So if we have this:
  div { margin: 10px 100px 10px 5px; }

then by defining

div:dir(rtl) { map: mirror-x margin; }

margins will be set to these values:
top/bottom: 10px, left:100px; right:5px;

Did we discuss similar approach already?

-- 
Andrew Fedoniouk.

http://terrainformatica.com