Earlier quoted context omitted.
But if you're passing a state object around, you might as well use a class, no? Admittedly simplifying a bit, an instance method is a function that implicitly takes "this" as the first argument.
There's one big difference in terms of convenience in many common implementations of classes and methods. There are essentially three different pieces involved: In OO notation, we have A.B(C) In almost all languages, you can store C in a variable and supply it "later": z = C A.B(z) You can also store A in a variable and supply it "later": x = A x.B(C) However, it is much more rare to be able to store B in a variable…
I like the approach Wouter van Oortmerssen uses in Lobster:
class Animal:
alive = true
class Cat : Animal
def hello(): print "meow"
class Dog : Animal
barked = 0
def hello(d::Dog):
print "bark!"
barked++
let d = Dog {}
d.hello()
let a:Animal = d
a.hello()