BEGIN { OFS="\t" }

{
  gsub("&", "\\\\&")
  id = $1
  type = $2
  year = substr($3, 1, 4) + 0
  title = $4
  if (type == "Single")
    line = format_single
  else if (type == "Album")
    line = format_album
  else if (type == "EP")
    line = format_ep
  else
    line = format_album
  if (year)
    line = line " " format_year
  sub("<<title>>", title, line)
  sub("<<year>>", year, line)
  print id, line
}