Source code in the icon programming language

procedure main()
    days := ["first","second","third","fourth","fifth","sixth","seventh",
             "eighth","ninth","tenth","eleventh","twelveth"]
    gifts := ["A partridge in a pear tree.", "Two turtle doves and",
              "Three french hens,", "Four calling birds,",
              "Five golden rings,", "Six geese a-laying,",
              "Seven swans a-swimming,", "Eight maids a-milking,",
              "Nine ladies dancing,", "Ten lords a-leaping,",
              "Eleven pipers piping,", "Twelve drummers drumming,"]

    every write("\nOn the ",days[day := 1 to 12]," day of Christmas my true love gave to me:") do
        every write(" ",gifts[day to 1 by -1])
end