[gpm]

What is a widget?

Is a text box with a reply button a widget? What about just a text box? What about just a button?

Assuming all three, it sounds like you have one widget composed of two other widgets, which naturally ends up creating tree structures.

[stephc_int13]

Do you think about code as a tree?

It is, in some ways, but this is not the best model to reason about code, IMHO.

[gpm]

I do when I'm trying to operate on it with other code (e.g. compile it - equivalently render the gui). Typically you parse it into a syntax tree.

[stephc_int13]

If you had to reason about your code as a tree when writing it, I think it would quickly be cumbersome. Remember that we're talking about the API here, not the internals of the implementation.

[gpm]

If I had to explicitly say "tree", I agree. But if what I was writing was in fact not a tree, I think it would be substantially more difficult.

Sound theoretical underpinnings are usually necessary for a coherent system that allows for good abstractions.

Note that in code while I don't say the word "tree" while writing it. I create a tree with my braces (C) or indentation levels (python) and file structure. The language designers created a syntax using a tree. And so on.

I guess what I'm saying is that while the tutorial should not say tree, and I should not be thinking about tree nodes and edges while writing it, I should be writing a tree (and in code I am).

[stephc_int13]

I almost never think about anything as a tree, especially when I am trying to solve a problem with code.

I am familiar with the structure, but I've never found it practical as an abstract tool.