-- Refs are global mutable (changing) values.
-- They let you break referential transparency (purity) to make some things easier.

x = ref!(1337). -- Construct a new ref, set to the value 1337
print(x). -- Should print <ref>
print(readRef!(x)). -- Should print 1337

setRef!(x, 42). -- Set it to 42
print(readRef!(x)).

-- Apply a function on the current value in the reference and set it to the new value.
modifyRef!(ref, f) ->
	setRef!(ref, f(readRef!(ref))).

modifyRef!(x, \v -> v*2). -- Double x
print(readRef!(x)). -- 84