//@version=6
indicator("Workshop 15 Dated Contracts", overlay=false)
near = input.symbol("CME_MINI:ESZ2026", "Near contract")
far = input.symbol("CME_MINI:ESH2027", "Far contract")
[a, nearTime] = request.security(near, timeframe.period,
    [close, time_close], gaps=barmerge.gaps_on,
    lookahead=barmerge.lookahead_off)
[b, farTime] = request.security(far, timeframe.period,
    [close, time_close], gaps=barmerge.gaps_on,
    lookahead=barmerge.lookahead_off)
aligned = (not na(a) and not na(b) and
    nearTime == farTime and nearTime == time_close)
spread = aligned ? a - b : na
plot(spread, "Near minus far in index points",
    color=color.blue, style=plot.style_linebr)
hline(0, "Equal quotes", color=color.gray)