Funnel

The Funnel operation joins many exclusive branches into one continuation. Each firing it passes to Out the one input that arrived on this firing — the lowest-numbered one when several did — and stops the path when none did. It is a router, not a transformer: it never inspects a value, so every port is Any.

With fewer than two inputs connected there is nothing to choose between, and the Editor shows an info badge on the Node saying so.

Inputs

Port	Type	Required	Description
In 1	Any	No	A branch’s value.
In 2	Any	No	Another branch’s value.
In (variable, up to 20 inputs in total)	Any	No	Further branches, added on demand in the Node’s Settings tab.

Every input is loose: the engine does not wait for its producer before running the Funnel, and the Editor offers no Validation rule on it. That is what lets each input sit on a branch the others exclude.

Outputs

Port	Type	Default	Description
Out	Any	Nil	The value of the input that arrived. Unchanged when none did.

Properties

Name	Type	Default	Description
On Error	Combo	Stop this branch	Per-op On Error verb (Stop this branch / Continue with the last value / Continue with the fallback). See the Error Handling guide.
Out → Fallback	bool / int / float / string	Nil	Per-output fallback value used when Continue with the fallback fires. Edit in Settings under the Out port.

State on Reload

Funnel keeps no value of its own. Out is preserved across restarts like any port, within the configured time window.

Everything after a Funnel must accept everything that can reach it

Out is Any, and the value it carries is whichever branch’s value arrived. A Node downstream of a Funnel sees, over time, every type its inputs can carry — so it must accept each of them, or a value it refuses fails that Node and its On Error verb resolves the failure.

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How It Works

1. Look for an arrival — In port order, top to bottom, the Funnel asks each input whether its producer wrote it on this firing.

2. One arrived — Its value is written to Out, stamped with this firing, and the path continues. A Debug status names the input taken, on every pass.

3. Several arrived — Priority is port order: the lowest-numbered input that arrived wins.

4. None arrived — Out is left alone and the path stops with an Information status. Nothing went wrong; every branch was skipped.

An arrival is a write on this firing — not a held value

A producer that kept its last value is not an arrival, however recent that value is. That covers an output a Node holds across firings, such as Constant’s, and a Node whose failure was resolved with Continue with the last value: its outputs are delivered to a plain dependent, which runs on the held value, but the Funnel does not take them. In the fallback chain below that is the wanted answer — the Secondary’s fresh value wins over the Primary’s held one. Wired straight to a Node under that verb with nothing else fresh, the Funnel reports that nothing arrived, which is what “last value” means.

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Use Cases

Finally

A step that must follow either outcome of a Node — acknowledge the device, release a lock, write the audit row, bump the attempt counter — drawn once.

Connect the Node’s value output to In 1 and the body of its error branch to In 2, and put the step after Out. Whichever branch ran, the step runs once, with one set of settings and one state, so a Node that carries either is not duplicated to drift.

Fallback chain

A Primary source on the trigger, a Secondary source gated by the Primary’s error output, both value outputs into a Funnel, and the processing off Out.

The processing receives the answer from whichever source produced one: the Primary’s when it succeeded, the Secondary’s when the Primary failed. Without the Funnel the two sources would need two copies of everything that follows.

Not for carrying on with a substitute value

A Funnel is for joining branches that produce a value. To carry on past a failure with a stand-in value, use the Node’s Continue with the fallback verb — that is what it is for.

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Error Handling

Funnel has nothing of its own to fail at: it reads no setting and inspects no value, so it fails only when the engine cannot read one of its inputs. The Node still carries an On Error verb and an error output like every Node — it is not infallible — and a failure is resolved by that verb:

Verb	What it does
Stop this branch (default)	This Node and its dependents stop; Out keeps its value, and the Node’s last attempt reads as failed.
Continue with the last value	Out keeps its value, not stamped as new; dependents run on it.
Continue with the fallback	Out takes its configured fallback as the value produced by this firing.

A firing on which nothing arrived is a stop, not a failure: no verb is consulted and the error output does not fire.