Paragraph formatting

[ssuukk]

Aaah,

As I see this list is not dead, I can finally ask my question. I am
trying to prepare Lout to Polish typographic standard and customs, and
one of them is the rule:

"Last line of a paragraph can not be shorter than paragraph
indentation"

(guess why? :-)

I suspect that the best way to do this is redefine PP, to add at the
end of paragraph something that must be of the width equal to line
width-indentation OR shorter. Or is there another way to achieve this?

TIA,

ssuukk