Variable Definitions

While I got the hang of some SC2 basics, I don't seem to be able to find some variable definitions by searching for them in the manual.

For example:

1) I was trying to understand the coding behind the Panning With Touch Controls example, which is pretty straightforward, but I could not find anything on the Touch.X("UI"). What is UI? Doesn't come up in the manual. I understand Touch.X, of course.

Second example:

2) This tutorial...

Smoke Trail Tutorial

refers to a lot of built in coding in SC2 itself (instance variables, indices...)

In trying to understand the code, I could not find anything on "parent" and I searched all instances of it in the manual. I sort of understand it, but it makes me wonder how many other things I don't know.

I would like to understand the code and what it's doing rather than just blindly copying people's examples every time I need something.

I did some programming in BASIC back in Commodore 64 days, but as a top level language I figure SC2 should not be that hard.

Where do I go to find out what's under the hood and how it works?

Does a tutorial have to exist to describe it?

Basically, rather than learning about everything piece by piece from other people's code, I'd like the whole breadth of it.

"Scroller" as in Scroller.Y would be another example from the Space Blaster demo.

Absolutely nothing comes up in the manual on keyword search.

If you don't understand what "parent" do in that "Smoke Trail Tutorial" you should really start here Beginner's guide to Construct 2

"UI" is the layer name.

X("layer")

Y("layer")

XAt(index, "layer")

YAt(index, "layer")

XForID(id, "layer")

YForID(id, "layer")

Return the current position of a touch in layout co-ordinates, with scrolling, scaling and rotation taken in to account for the given layer. The layer can be identified either by a string of its name or its zero-based index (e.g. Touch.X(0)). The At expressions can return the position of any touch on a layer given its zero-based index, and the ForID expressions return the position of a touch with a specific ID.

https://www.scirra.com/manual/119/touch

'parent' in that example is an instance variable that has been added to the Particles object.

https://www.scirra.com/manual/73/instance-variables

And "Scroller" is a just the name of a sprite.

Alright, guess I was having a brain fart.

(This explains all the bad vibes I was getting <img src="smileys/smiley17.gif" border="0" align="middle" />)

This is what happens when you post late and are exhausted.

But thanks. This makes it clear.

(I'm not a youngin btw, so things that seem obvious to people may not be so much for me.)

I was going through some other examples where people were doing things in a fancy way with function calls and what not and I thought this was referring to some built-in functionality I could not find anything about.

I still don't understand the purpose of the "scroller" sprite in the Space Blaster example and when you go to far up, the ship appears to jump down, but no biggie. I already set up custom boundaries.

I'm still having trouble with custom touch controls. It works the way I set it up, but sporadically for one of the boundaries.

I'll post an example in a bit for critique.