1 val http_pattern = """\"https?://[^\"]*\"""".r

     2 

     3 def unquote(s: String) = s.drop(1).dropRight(1)

     4 

     5 def get_all_URLs(page: String) : Set[String] = {

     6   (http_pattern.findAllIn(page)).map { unquote(_) }.toSet

     7 }

     8 

     9 def crawl(url: String, n: Int) : Unit = {

    10   if (n == 0) ()

    11   else {

    12     println("Visiting: " + n + " " + url)

    13     for (u <- get_all_URLs(get_page(url))) crawl(u, n - 1)

    14   }

    15 }

    16