Would it be possible to get value of element during table construction?

[Layback_]

Hi again all,

The title says everything.

I was trying to create a configuration table for my castbar and just got a question regarding table construction.

Let's say I have a simple table like this:

G["castbar"] = {
    ["player"] = {
        ["width"] = 350,
        ["height"] = 35,
        ["point"] = {"CENTER", UIParent, "CENTER", 250, -200},
        ["iconSize"] = 35,
        ["spacing"] = 2,
    },
}

As you can see, height and iconSize have a same value and this is because I would like the icon to be the same size as the castbar's height.

Of course, I could do something like

G["castbar"] = {
    ["player"] = {
        ["width"] = 350,
        ["height"] = 35,
        ["point"] = {"CENTER", UIParent, "CENTER", 250, -200},
        ["spacing"] = 2,
    },
}
G["castbar"]["player"]["iconSize"] = G["castbar"]["player"]["height"];

and this will definitely work without any issues.

However, as I add target's castbar, targettarget's castbar, party1's castbar and so on, this would look ugly and would be complex for me to manage with.

e.g:

G["castbar"] = {
    ["player"] = {
        ["width"] = 350,
        ["height"] = 35,
        ["point"] = {"CENTER", UIParent, "CENTER", 250, -200},
        ["spacing"] = 2,
    },
    ["target"] = {
        ["width"] = G["unitframe"]["target"]["width"],
        ["height"] = 20,
        ["point"] = {"TOP", UIParent, "BOTTOM", 0, 200},
        ["iconSize"] = 20,
    },
}
G["castbar"]["player"]["iconSize"] = G["castbar"]["player"]["height"];
G["castbar"]["target"]["spacing"] = G["castbar"]["player"]["spacing"];
.
.
.

I also tried something like the following and this doesn't seem to be working. I'm guessing that this is because the table G["castbar"] does not exist yet, since it is on the way of its construction.

G["castbar"] = {
    ["player"] = {
        ["width"] = 350,
        ["height"] = 35,
        ["point"] = {"CENTER", UIParent, "CENTER", 250, -200},
        ["iconSize"] = G["castbar"]["player"]["height"],
        ["spacing"] = 2,
    },
}

To gain some idea, I have gone through the official references, but could have not found anything close to this...

Would there be any possible approach to achieve something similar to the above?

Thank you.