Module subgraph 

Subgraph Support for LangGraph

Subgraphs allow nesting compiled graphs within nodes of a parent graph. This enables composition of complex workflows from simpler components.

Example

use lc_langgraph::{StateGraph, CompiledGraph, SubgraphNode, START, END};

// Create subgraph
let subgraph = GraphBuilder::<AgentState>::new()
    .add_node_fn("process", |state| Ok(StateUpdate::full(state.clone())))
    .add_node_fn("output", |state| {
        let mut s = state.clone();
        s.set_output("done");
        Ok(StateUpdate::full(s))
    })
    .add_edge(START, "process")
    .add_edge("process", "output")
    .add_edge("output", END)
    .compile()?;

// Add as subgraph node in parent graph
let parent = GraphBuilder::<AgentState>::new()
    .add_subgraph("subworkflow", subgraph,
        |parent_state| parent_state.clone(),  // input mapper
        |sub_state, parent_state| *parent_state = sub_state.clone()  // output mapper
    )
    .add_edge(START, "subworkflow")
    .add_edge("subworkflow", END)
    .compile()?;

Structs

SubgraphBuilder

Builder for creating subgraph nodes with fluent API

SubgraphNode

Subgraph Node - A node that executes a nested compiled graph