Loop and workflow control — node reference

Loop, switch, and error handling nodes are in the node repository under Workflow Control.

Loop nodes

A loop consists of a Loop Start node, a loop body, and a Loop End node. Loop nodes are under Workflow Control → Loop Support.

Loop start nodes

Node	Iterates over
Counting Loop Start	A fixed number of iterations
Chunk Loop Start	Consecutive chunks of a table (configurable by number of chunks or rows per chunk)
Column List Loop Start	A list of columns
Generic Loop Start	Iterations until a condition in a Variable Condition Loop End is met
Table Row to Variable Loop Start	Rows of a table, converting each row to flow variables
Group Loop Start	Groups of rows with the same values in one or more selected columns
Interval Loop Start	A numeric interval, incrementing a variable each iteration
Recursive Loop Start	Iterations using the previous iteration's output as the next iteration's input
Recursive Loop Start (2 Ports)	Same as Recursive Loop Start, with two input/output table ports
Window Loop Start	Sliding windows of rows, defined by row count or time

Loop end nodes

Node	Output behaviour
Loop End	Concatenates output tables from all iterations row-wise
Loop End (2 Ports)	Concatenates into two separate output tables
Loop End (Column Append)	Joins iteration outputs column-wise
Recursive Loop End	Returns output to a Recursive Loop Start for the next iteration
Recursive Loop End (2 ports)	Returns two output tables to a Recursive Loop Start (2 Ports)
Variable Condition Loop End	Stops the loop when a flow variable condition is met; used with Generic Loop Start
Variable Loop End	Collects flow variables from each iteration; outputs a table with one row per iteration and the selected variables as columns

Loop execution options

The Loop End node context menu provides the following options:

Option	Behaviour
Execute	Runs all iterations to completion
Step loop	Runs one iteration and pauses
Resume loop	Continues from a paused state
Pause loop	Pauses after the current iteration completes
Cancel	Stops execution immediately

The node action bar at the top of the Loop End node provides quick access to the same options.

Breakpoint node

The Breakpoint node halts execution when a configurable condition is met:

• A flow variable equals a specified value
• The input table is empty
• The branch is active
• The branch is inactive

A custom message is displayed when the condition triggers.

Switch nodes

Switch nodes activate or deactivate workflow branches. They are under Workflow Control → Switches.

IF Switch

The IF Switch node has two output branches — top and bottom. One or both can be active. The active branch is set in the dialog via Select active port (top, bottom, or both). A string flow variable with one of those values can overwrite this setting.

An End IF node merges branches after the switch.

CASE Switch Data (Start)

The CASE Switch Data (Start) node has three output branches. The active branch is set in the dialog. An integer flow variable can overwrite this setting: 0 for top, 1 for middle, 2 for bottom.

A CASE Switch Data (End) node collects the output of whichever branch was active.

Error handling nodes

Error handling nodes are under Workflow Control → Error Handling.

A Try-Catch enclosure consists of:

Node	Role
Try (Data Ports) / Try (Variable Ports)	Marks the start of the guarded section
Active Branch Inverter	Activates on failure; deactivates on success
Catch Errors (variant)	Closes the enclosure; routes to the default or catch branch

The Catch Errors node top input port receives the successful branch output; the bottom port receives the failure branch output. Its flow variable output carries the failure reason.

Catch Errors variant	Branch output type
Catch Errors (Data Ports)	Tables
Catch Errors (Var Ports)	Flow variables
Catch Errors (Generic Ports)	Any port type, such as models