-- helper function:
-- create a formspec dropdown list with player names (first entry: Add player) and
-- an option to delete players from that list
yl_speak_up.create_dropdown_playerlist = function(player, pname,
		table_of_names, index_selected,
		start_x, start_y, dropdown_name,
		field_name_for_adding_player, explain_add_player,
		field_name_for_deleting_player, explain_delete_player)

	local text = "dropdown["..tostring(start_x)..","..tostring(start_y)..";3.8;"..
				tostring(dropdown_name)..";Add player:"
	-- table_of_names is a table with the playernames as keys
	-- we want to work with indices later on; in order to be able to do that reliably, we
	-- need a defined order of names
	local tmp_list = yl_speak_up.sort_keys(table_of_names, true)
	for i, p in ipairs(tmp_list) do
		text = text..","..minetest.formspec_escape(p)
	end
	-- has an entry been selected?
	if(not(index_selected) or index_selected < 0 or index_selected > #tmp_list+1) then
		index_selected = 1
	end
	text = text..";"..tostring(index_selected)..";]"
	if(index_selected == 1) then
		-- first index "Add player" selected? Then offer a field for entering the name
		text = text.."field["..tostring(start_x + 4.0)..","..tostring(start_y + 0.3)..";3.5,0.9;"..
				tostring(field_name_for_adding_player)..";;]"..
				"tooltip["..tostring(field_name_for_adding_player)..";"..
					"Enter the name of the player whom you\n"..
					"want to grant the right to "..tostring(explain_add_player).."]"
	else
		text = text.."button["..tostring(start_x + 3.8)..","..tostring(start_y)..";3.5,0.9;"..
				tostring(field_name_for_deleting_player)..";"..
				"Remove player from list]"..
				"tooltip["..tostring(field_name_for_deleting_player)..";"..
					"If you click here, the player will no\n"..
					"longer be able to "..tostring(explain_delete_player).."]"
	end
	return text
end