scavenge_urls.erl

-module(scavenge_urls).
-export([urls2htmlFile/2, bin2urls/1]).
-import(lists, [reverse/1, reverse/2, map/2]).

urls2htmlFile(Urls, File) ->
	file:write_file(File, urls2html(Urls)).

bin2urls(Bin) -> gather_urls(binary_to_list(Bin), []).

urls2html(Urls) -> [h1("URLs"), make_list(Urls)].

h1(Title) -> ["<h1>", Title, "</h1>\n"].

make_list(L) ->
	["<ul>\n",
	 map(fun(Item) -> ["<li>", Item, "</li>\n"] end, L),
	 "</ul>\n"
	].

gather_urls("<a href=" ++ T, L) ->
	{Url, T1} = collect_url_body(T, reverse("<a href=")),
	gather_urls(T1, [Url|L]);
gather_urls([_|T], L) -> gather_urls(T, L);
gather_urls([], L) -> L.

collect_url_body("</a>" ++ T, L) -> {reverse(L, "</a>"), T};
collect_url_body([H|T], L)       -> collect_url_body(T, [H|L]);
collect_url_body([], _)          -> {[], []}.