What Does `:=` Do?

[Mason]

@ParadaCarleton

What the title says. I can’t figure it out, and the docs just provide the not at all useful description:
x := y is a synonym for x = x : y

That’s actually an error in the docs that I believe was recently fixed. := doesn’t do anything. It’s basically just reserved syntax for macros.

E.g. some people want domain specific languages embedded in julia might have a syntax like

@model begin
    x := 1
    y := x + 1
    ...
end