Gadfly (Julia): how to add text annotation to a plot?

In Stata I can add text to a plot at given coordinates, e.g.:

clear

set obs 10

gen x = rnormal()
gen y = rnormal()

twoway scatter y x, text(0.8 0.8 "Some text")

The result is "Some text" at coordinates (0.8, 0.8):

I want to add a similar annotation in Julia with Gadfly. I found Guide.annotation that can add layers of graphs and I could not figure out how to apply it to text instead of shapes. The documentation mentions at the top:

Overlay a plot with an arbitrary Compose graphic.

but the Compose link shows a website in Chinese.

How can I add a text label (or caption, or annotation) with Gadfly?

You can check the guide on Compose in julia. In the example in your link they use Circle, but you just as easily can use:

text(x, y, value)

or using the linked example code:

Pkg.add.(["Gadfly", "Compose"])
using Gadfly, Compose;
plot(x = rand(10),
     y = rand(10),
     Guide.annotation(compose(context(), text(0.8, 0.8, "Some text"))))

in the link I provided they redirect to a source file for the comprehensive list:

These are basic constructors for the in-built forms - see src/form.jl for more constructors.

• polygon(points)

• rectangle(x0, y0, width, height)

• circle(x, y, r)

• ellipse(x, y, x_radius, y_radius)

• text(x, y, value)

• line(points)

• curve(anchor0, ctrl0, ctrl1, anchor1)

• bitmap(mime, data, x0, y0, width, height)