How do I plot more than one graph on the same axes?

[Andrew]

@chyavana

I can get the $x^x$ curve but not the horizontal line, even though the CeTZ-plot manual refers to it.

The manual clearly uses curly braces for plot.add’s body.

#import "@preview/cetz:0.4.0"
#import "@preview/cetz-plot:0.1.2": plot

#cetz.canvas({
  plot.plot(size: (12, 10), {
    plot.add(domain: (1.5, 2.5), x => calc.pow(x, x))
    plot.add-hline(7)
  })
})