Struct LoopNode 

pub struct LoopNode { /* private fields */ }

Loop node - controlled iteration.

Implements a loop construct for repeated execution. The loop continues until an exit condition is met. Loop back-edges must be declared in the flow topology to be excluded from cycle detection.

Ports

• Input: “in” - Initial input / data from loop body
• Output: “continue” - Activated to continue the loop
• Output: “exit” - Activated when loop terminates

Example Configuration

nodes:
  retry_loop:
    type: std::loop
    config:
      max_iterations: 3
      # Or: until_true: $.success
      # Or: until_expression: "${iteration} >= 3 || ${result.success}"
    inputs:
      - from: start.out -> in
      - from: retry_action.out -> in  # back-edge from loop body
    outputs:
      continue: -> retry_action.in
      exit: -> done.in

Back-edge Declaration

topology:
  loop_edges:
    - from: retry_action
      to: retry_loop  # This edge is treated as a back-edge

Implementations

impl LoopNode

pub fn with_max_iterations(max: u32) -> Self

Create a loop with max iterations exit condition.

pub fn until_field_equals( field: impl Into<String>, value: impl Into<String>, max_iterations: u32, ) -> Self

Create a loop that runs until a field equals a value.

pub fn until_true(field: impl Into<String>, max_iterations: u32) -> Self

Create a loop that runs until a boolean field is true.

pub fn with_expression(expr: impl Into<String>, max_iterations: u32) -> Self

Create a loop with a custom exit expression.

Trait Implementations

impl Debug for LoopNode

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Node for LoopNode

fn info(&self) -> NodeInfo

Get metadata about this node.

fn execute<'a>( &'a self, ctx: Context, inputs: HashMap<String, RelPtr<()>>, ) -> NodeFuture<'a>

Execute the node.

fn shutdown(&self)

Called when the node is being shut down.

fn output_schema_hash(&self) -> u64

Get the schema hash for this node’s output type.