[3.x] Add print_verbose() built-in function to print in verbose mode only

[Calinou]

3.x version of #52877. Unlike #52877, this also adds C# support for print_verbose().

This can be used as a shorthand for:

if OS.is_stdout_verbose():
    print("...")

Unlike print_debug(), this works in release builds too and can be toggled off in debug builds.

Preview

extends Node

func _ready():
	print("normal", " and ", "verbose")
	print_verbose("verbose", " only")

Verbose mode disabled

normal and verbose

Verbose mode enabled

Enable verbose stdout in the advanced project settings:

Alternatively, you can start Godot with the --verbose/-v command line argument.

normal and verbose
verbose only

[neikeq]

I think it was said a few times that we should add proper logging, specially various logging levels. If that is really going to happen in the future then it might be better not to add this for now as it could break later (and it's easy to do as a custom function already). Ah, never mind. This is the 3.x version. The master one is already merged. Too late I guess.

[neikeq]

I'm not a big fan of print_verbose because it always allocates. It can (and probably should) be replaced with a macro in C++ to avoid that, but for most language bindings it's unavoidable. C# and GDScript don't support lazy evaluation of arguments (neither does C++ tbh, but macro magic).