[EP-tech] Rendering a metafield - use different format in Listing and Abstract page

[J.Salter at leeds.ac.uk (John Salter)]

Hi,
I'd like to be able to apply a different rendering to a field if it's being displayed in a listing (e.g. the Review screen) to how it gets rendered 'normally'.

In this specific case, a compound field is normally rendered as a table:
+----------+----------+
| Sub A    | Sub B    |
+----------+----------+
| Val 1A   | Val 1B   |
| Val 2A   | Val 2B   |
| Val 3A   | Val 3B   |
+----------+----------+

This rendering is OK on an abstract page, but when using the compound field as a review column, I want to render is as a list:
* Val 1B (Val 1A)
* Val 2B (Val 2A)
* Val 3B (Val 3A)

Is there a way (in the render_value of a field) to determine if the field is being rendered as part of a listing?
I've got access to the $session - so was thinking along the lines of (CAUTION: nonsense code!)
if( $session->{screen}->isa( "EPrints::Screen::Listing" ) ){
	#do list rendering
} else {
	#revert to normal table rendering
}

but I can't quite get my head around going from session to screen. Any pointers welcome!

I may be missing something obvious too - e.g. if there's a citation style that I should use to do this!

Cheers,
John