Panicker = Object clone do:
  { yield: v := error: v
  }

define: handler as: Panicker

try: action catch: rescue :=
  { cc |
    with: handler as: cc do: action
  } call/cc match: {
    @(exception: x) -> rescue call: x
    ok -> ok
  }

throw: v :=
  handler _? yield: @(exception: v)

try: {
  try: {
    "before" print
    throw: @foo
    "after" print
  } catch: { exn |
    @(got-inner: exn) print
    throw: @bar
    "after again" print
  }
} catch: { exn |
  @(got-outer: exn) print
}