Can't print custom variable to alert message in Pine Script

Question

I'm trying to get my alert message to print a variable that is defined earlier in my script. Here's the alertcondition() part of my code:

var bool alerttrigger = true
WaveTrend1val = wt1
strWaveTrend1val = tostring(WaveTrend1val)
alertcondition(alerttrigger, title="Test alert", message=strWaveTrend1val)
//plot(WaveTrend1val, "WaveTrend1val")

Just make the trigger True all the time for testing purposes. wt1 is a value that is defined within this function:

f_wavetrend(src, chlen, avg, malen, tf) =>
    tfsrc = security(syminfo.tickerid, tf, src)
    esa = ema(tfsrc, chlen)
    de = ema(abs(tfsrc - esa), chlen)
    ci = (tfsrc - esa) / (0.015 * de)
    wt1 = security(syminfo.tickerid, tf, ema(ci, avg))
    wt2 = security(syminfo.tickerid, tf, sma(wt1, malen))
    wtVwap = wt1 - wt2
    wtOversold = wt2 <= osLevel
    wtOverbought = wt2 >= obLevel
    wtCross = cross(wt1, wt2)
    wtCrossUp = wt2 - wt1 <= 0
    wtCrossDown = wt2 - wt1 >= 0
    wtCrosslast = cross(wt1[2], wt2[2])
    wtCrossUplast = wt2[2] - wt1[2] <= 0
    wtCrossDownlast = wt2[2] - wt1[2] >= 0
    [wt1, wt2, wtOversold, wtOverbought, wtCross, wtCrossUp, wtCrossDown, wtCrosslast, wtCrossUplast, wtCrossDownlast, wtVwap]

and then it is plotted to my chart using this code:

plot(wtShow ? wt1 : na, style = plot.style_area, title = 'WT Wave 1', color = macdWTColorsShow ? macdWT1Color : colorWT1, transp = 0)

I can easily plot() the value of wt1 in the last line of the first code block, but when I try to convert the float value to a string and print it in the alert message, I get the following error:

Cannot call 'alertcondition' with 'message'=series[string]. The argument should be of type: const string

I first tried to print the value using {{wt1}} in the alert message, but I think this only works for the built-in placeholders, such as {{time}} or {{close}}. It look like I'm converting the whole series of values of wt1 to a string, but I also tried tostring(wt1[0]) to get only the latest value of wt1 rather than the entire series, but I get the exact same error.

Answer 1

Funny that I've managed to find an answer by myself literally minutes after posting this, but I spent about 3 hours before trying to find and figure out a solution so I'll post my solution here instead of deleting the question, just in case someone else finds it helpful.

The solution I found was to reference the plot itself. So the plot name for the wt1 values is "WT Wave 1". Can reference the plot in the alert message like so:

alertcondition(alerttrigger, title="Test alert", message='TEST: {{plot("WT Wave 1")}}')

This puts in the latest value from the plot into the alert message so that it reads something like "TEST: 43.520", or whatever the value is.

Here's a link to the page that I found the solution on that goes into more detail about the {{placeholders}} used in alert messages: https://kodify.net/tradingview/alerts/alert-variables/

Answer 2

Yes you can use the names of the plots or their indices. So for example in the picture below if you want to plot the value of "EMA Slow" you can use either {{plot_0}} or {{plot("EMA Slow")}} in the alert message.