[ownedbycats]

Ok I did some more tinkering of the code on #7 and tweaked the regexes a bit (^.*/(\d+)$ occasionally captured chapter numbers instead of the story id).

program:
	publisher = field('publisher');
	ids = field('identifiers');
	status = field('#fanficstatus');
	u = select(ids, 'url');

	if publisher == 'Archive of Our Own' && u && status != 'Anthology' then
		ids = list_difference(ids, strcat('url:', u), ',');
		n = re(u, '^https://archiveofourown.org/works/(\d+)', '\1');
		ids = list_union(ids, strcat('ao3:', n), ',')
	fi;

	if publisher == 'FanFiction.net' && u && status != 'Anthology' then
		ids = list_difference(ids, strcat('url:', u), ',');
		n = re(u, '^https://www.fanfiction.net/s/(\d+)/(\d+)/', '\1');
		ids = list_union(ids, strcat('ffnet:', n), ',')
	fi;

	if 'Completed|Oneshot|Abandoned' in status && u &&
		(select(ids, 'ao3') || select(ids, 'ffnet')) then
		ids = list_difference(ids, strcat('url:', u), ',')
	fi;
	ids

Oddly enough if I remove the last part it still removes the url: identifier

I will keep tinkering.

EDIT: If I remove the list_difference lines (except the last one), it does not remove url: Is that necessary for something else to work? I did not see any strange results when I tried with multiple books of different statuses