hakorune/examples/jit_policy_optin_mutating.hako

// Demonstrate JIT mutating opt-in via JitPolicyBox whitelist
// 1) Enable read_only → mutating hostcalls fallback (policy_denied_mutating)
// 2) Whitelist nyash.array.push_h → allow + execute
// Run:
//   NYASH_JIT_EXEC=1 NYASH_JIT_THRESHOLD=1 NYASH_JIT_HOSTCALL=1 NYASH_JIT_EVENTS=1 \
//     ./target/release/nyash --backend vm examples/jit_policy_optin_mutating.hako

box Helper {
  birth() {}
  add(a) {
    a.push(1)
    return a.length()
  }
}

static box Main {
  main() {
    local P, H, A
    P = new JitPolicyBox()
    // Enable read-only first (deny mutating)
    P.set("read_only", true)

    H = new Helper()
    A = new ArrayBox()
    // This call will fallback by policy (observe events)
    H.add(A)

    // Opt-in: allow array.push_h through whitelist
    P.setWhitelistCsv("nyash.array.push_h")

    // This call will be allowed (observe allow event)
    return H.add(A)
  }
}