[eschwartz]

Try:

program:

# return separator+authors if Multi Autor Serie (MAS) is not found, or return empty
various_authors=str_in_list(
	field('tags'),
	',',
	'MAS',
	'',
	 strcat(' - ', field('authors'))
);
sindex=str_in_list(
	field('tags'),
	',',
	'MAS',
	finish_formatting(field('series_index'), '0>5.2f', ' ', ' - '),
	finish_formatting(field('series_index'), '0>4s', ' ', ' - ')
);
start_template=test(
	field('series'),
	strcat(
		'_ ',
		field('series'),
		various_authors
	),
	field('authors')
);

strcat(start_template, '/', sindex, field('title'), ' - ', field('authors'));