[ownedbycats]

Another example:

program:	
	if
		is_marked()
	then
		m = is_marked();
		switch_if(
			'reading_list_send_to_device' in m, 'sync.png',
			'reading_list_to_be_read' in m, 'list.png',
			'fff' in m, 'download-metadata.png',
			'marked.png'
		)
	fi

Original. (Trying to figure out why I used a 'contains' instead of 'in'.)

Spoiler:

program:	
	if is_marked() then
		m = is_marked();
		first_non_empty(
			if 'reading_list_send_to_device' in m then 'sync.png' fi,
			if 'reading_list_to_be_read' in m then 'list.png' fi,
			contains(m, "fff", 'download-metadata.png', ''),
			if m then 'marked.png' fi
		)
	fi