Allow to reference any datasets from quandl.com
study("QUANDL")
code = input("", type=string, title="QUANDL Code", confirm=true)
index = input(0, title="Data Set Index", minval = 0, maxval = 99, confirm=true)
quandl_ticker = "QUANDL:" + code + (index == 0 ? "" : "|" + tostring(index))
quandl = security(quandl_ticker, "D", close)
plot(quandl, color=green)