apfl/src/functional-tests/function-mutable-capture.at

===== script =====
counter = {
    i = 0
    { i = + i 1 }
}

c1 = (counter)
c2 = (counter)

print (c1)
print (c2)
print (c1)
print (c2)
print (c2)
print (c1)
print (c2)

===== output =====
1
1
2
2
3
3
4