As far as i know there are no named parameter in GDScript so you can't do this like in python:
def foo(a,b=1,c=2):
....
foo("first param", c=5)
gdScript supports optional parameter tho.
func foo(a,b=1,c=2):
...
foo("first param", "second param") # the third parameter will have the default value "2"
If you really need the behavior of named parameter i suggest using a dictionary like:
func foo(params={}):
var a = (1 if not params.has('a') else params['a'])
var b = (2 if not params.has('b') else params['b'])
var c = (3 if not params.has('c') else params['c'])
prints(a, b, c)
foo({a="first param", c="third param"})