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State

rust_langgraph::state

Trait State 

Source 
pub trait State:
    Clone
    + Send
    + Sync
    + Serialize
    + for<'de> Deserialize<'de>
    + Debug
    + 'static {
    // Required method
    fn merge(&mut self, other: Self) -> Result<()>;

    // Provided methods
    fn to_value(&self) -> Result<Value> { ... }
    fn from_value(value: Value) -> Result<Self> { ... }
}
Expand description

The core trait for graph state.

Implementors of this trait define how state is merged when multiple nodes produce updates that need to be combined.

§Example

use rust_langgraph::{State, Error};

#[derive(Clone, Debug, serde::Serialize, serde::Deserialize)]
struct CounterState {
    count: i32,
}

impl State for CounterState {
    fn merge(&mut self, other: Self) -> Result<(), Error> {
        self.count += other.count;
        Ok(())
    }
}

Required Methods§

Source

fn merge(&mut self, other: Self) -> Result<()>

Merge another state into this one.

This is called when multiple nodes write to the same state, or when resuming from a checkpoint.

Provided Methods§

Source

fn to_value(&self) -> Result<Value>

Convert state to JSON value (default implementation)

Source

fn from_value(value: Value) -> Result<Self>

Create state from JSON value (default implementation)

Dyn Compatibility§

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors§