#!/usr/bin/env catnip
# Membership operators: in / not in

# in

3 in list(1, 2, 3, 4, 5)
# → True

"cat" in "catnip"
# → True

"z" in dict(a=1, b=2)
# → False

# not in

42 not in set(1, 2, 3)
# → True

# usage in control flow

allowed = list("admin", "editor")

check = (role) => {
    if role in allowed {
        "granted"
    } else {
        "denied"
    }
}

check("admin")   # → "granted"
check("viewer")  # → "denied"

# custom struct with op in

struct Bag {
    items

    op in(self, item) => { item in self.items }
}

b = Bag(list(1, 2, 3))

2 in b
# → True

5 not in b
# → True