How to pass a table or rows to a function in Postgresql?

Here is the code, the current type of argument is array, but I want to pass a table or rows instead.

create or replace function skyband_sortedlist(rest point[]) 
    returns setof point
as $$ 
declare

    last_x integer :=0;
    last_y integer :=0;
begin
    for ipoint in (select s0.x,s0.y from unnest(rest))
    loop 
        if ipoint.x>last_x and ipoint.y<>last_y then
            last_x = ipoint.x;
            last_y = ipoint.y;
            return next;
        end if;
    end loop;
end;
$$ language plpgsql;