linebuf : [256]u8 = uninitialized
linepos : size = 0;

append :: action capture(linebuf, linepos) receive(s: str)
do
    linebuf.append(
end

define reset(linebuf) :: clear_to_zero(linebuf);
define reset(linepos) :: linepos = 0;

foreach (line in lines)
do
    reset linebuf, linepos;

    if line.starts_with("# ")
	append "<h1>";
	append line[2..];
	append "</h1>";
    ...

    # handle @@[][]
    i : size = 0;
    while (line.locate_next("@@[")) |pos|
    do
	std.mem.copy(dest: linebuf, src: line, from: i, to: pos);
	append line[from:pos];

    end


end