LangGraph의 Rust 구현체인 Juncture 공개

use juncture::prelude::*;
use serde::{Deserialize, Serialize};

[derive(State, Clone, Debug, Serialize, Deserialize)]
struct MyState {
    #[reducer(replace)] count: i32,
    #[reducer(append)] history: Vec<String>,
}

async fn increment(state: &MyState) -> Result<MyStateUpdate, Box<dyn std::error::Error>> {
    Ok(MyStateUpdate {
        count: Some(state.count + 1),
        history: Some(vec![format!("count -> {}", state.count + 1)]),
    })
}

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let mut graph = StateGraph::<MyState>::new();
    graph.add_node("increment", increment);
    graph.add_edge(START, "increment");
    graph.add_edge("increment", END);

    let compiled = graph.compile()?;
    let result = compiled
        .invoke(MyState { count: 0, history: vec![] }, &RunnableConfig::default())
        .await?;

    println!("Result: {:?}", result);
    Ok(())
}