# `Statifier.Effect.Autoforward`
[🔗](https://github.com/riddler/statifier-ex/blob/v2.0.0/lib/statifier/effect/autoforward.ex#L1)

Payload for `{:autoforward, %__MODULE__{}}` - spec 6.4's `autoforward`
attribute, Appendix D's `if inv.autoforward: send(inv.id, externalEvent)`
in `mainEventLoop`'s finalize/autoforward pass (`:152-158`). `invoke_id`
names the invocation to forward to; `state_index` is the constraint-3
identity of the invoking state; `event` is the external event that
triggered the pass, carried verbatim; `macrostep`/`microstep`/`round` are
the counters as they stood at the moment of the pass.

## Not `Statifier.Effect.Send` to `"#_" <> invoke_id`

`Effect.Send` describes an event to be *built* from a `<send>` element's
own attributes (`event`, `eventexpr`, `<param>`/namelist) - it has no way
to carry an existing `Statifier.Event.t()` through unchanged. Spec 6.4 is
explicit that autoforwarding needs exactly that: "All the fields specified
in 5.10.1 (event name, data etc.) MUST have the same values in the
forwarded copy of the event". Routing the pseudocode's `send(inv.id,
externalEvent)` through `Effect.Send` would lose `sendid`, `origin`, and
`invokeid` on the way through - the same fields `Statifier.Event`'s own
moduledoc says a caller of this pass is the first reader of - so this
effect carries `event` whole instead of decomposing it into `Effect.Send`'s
build-from-attributes shape.

## One effect per autoforwarding invocation

Every other effect this vocabulary produces is one-per-action
(`Effect.Invoke` is one-per-`<invoke>`, `Effect.CancelInvoke` is
one-per-cancelled invocation); a state with two autoforwarding invocations
therefore emits two `Autoforward` effects, never one carrying a list.

# `t`

```elixir
@type t() :: %Statifier.Effect.Autoforward{
  event: Statifier.Event.t(),
  invoke_id: String.t(),
  macrostep: non_neg_integer(),
  microstep: non_neg_integer(),
  round: non_neg_integer(),
  state_index: non_neg_integer()
}
```

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*Consult [api-reference.md](api-reference.md) for complete listing*