gdscript debugging enhancements re: visibility of variable values (watch window and improved locals view)

[samtsejerome]

Describe the project you are working on

a 2d platformer

Describe the problem or limitation you are having in your project

it would make debugging a lot easier to be able to see. the value of locals and custom expressions whilst using the godot debugger, I've been trying to manage with just the tooltips but its really hard work, and not conducive to productivity.
the locals window is virtually unusable its so awkward to use,and theres no way to see the value of a custom expression.

Describe the feature / enhancement and how it helps to overcome the problem or limitation

add a watch window/pane to watch the values of variables and expressions of the users choosing.

• make the locals window simpler to use.

Describe how your proposal will work, with code, pseudo-code, mock-ups, and/or diagrams

a "watch" window containing watched expressions that are customisable

an "add watch" option on selected text in the editor would be convenient too.

If this enhancement will not be used often, can it be worked around with a few lines of script?

no it can't.

Is there a reason why this should be core and not an add-on in the asset library?

gdscript is central to the engine, and debugging is an essential part of development -

its currently quite limiting.

[Calinou]

Duplicate of #1074.