Named Arguments

Another way to pass arguments to a func is to name them when calling. Normally when you call a func, the arguments used will be placed in the func’s arguments in the order they are set when you call that func.

proc/SomeProc(a, b, c)
  world << "[a] is first, [b] is second, [c] is third."

proc/Main()
  SomeProc(1, 2, 3) // 1 goes to a since it's first in the list and so on...

However, you can specify the order using named arugments.

proc/Main()
  SomeProc(c = 3, b = 2, a = 1) // will produce the same result as above...

This is mainly useful for ensuring that the right variables go to the right arguments since order doesn’t matter when using names.

Note: Named arguments that don’t match any of the arguments in the proc you call will produce a runtime error. You’ll learn more about these later on.

Examples

Named arguments are most useful when a proc has several optional arguments with defaults. Instead of counting commas until you reach the setting you want to change, you can name only the one you care about.

/proc/show_popup(txt, c = "blue", b = FALSE, w = 2, t = 3)
  world.log << "[txt] | c=[c] | b=[b] | w=[w] | t=[t]"

/proc/main()
  show_popup("Testy")
  show_popup("Oh No", c = "teal", b = TRUE)
  show_popup("Quick", t = 10)
  show_popup("Mixed", "blue", t = 5)

That last call mixes both styles: "Mixed" and "blue" are positional, while t = 5 is named.

This makes longer calls easier to read, easier to change later, and much harder to mix up.

Mixing Positional and Named Arguments

You do not have to use names for every argument in a call. DM lets you mix positional arguments with named ones.

proc/Main()
  SomeProc(1, b = 2, c = 3)

Here, 1 is still passed into a because it is first in the argument list, while b and c are matched by name.

However, this can be confusing.