There is support for that, but if you want to use scripting functions you'll have to swap your tags through the filename.
ALBUM='%artist%' puts 'Beatles' into the ALBUM field as you would expect. The scripting functions do not work however.
'$caps("%artist%")' comes out '$caps("Beatles")'
This appears to work in the grid, but as I later found out, '%artist%' is written to the tag and not 'Beatles', although showing as such in the grid.