How to throw an exception at compile time

# https://ask.godotengine.org/54948/throw-exception-or-error
assert( required_var != "", "ERROR: You must give required_var a value.");

https://ask.godotengine.org/54948/throw-exception-or-error

How to get index in a for-in loop

for i in len(selected_units):
    var unit = selected_units[i]

Get type of obj / built-in

# get type and name of node
node.name # get name of node
node.getClass() # get type of node

# get type of variable?
typeof("valume") ## ??? TODO: Verify

https://ask.godotengine.org/13029/is-there-a-corresponding-type-function-in-gdscript

How to pass through clicks from HUD layer to lower click targets

Control->Mouse->Filter->Ignore/Pass through

By default it's stop which prevents the event from being passed through.

Godot does method overloading

so calling

someFunc('hello')

won't call this because the arity doesn't match

func someFunc():
  pass

How to set button_group in gdscript

doesn't seem to be possible :(