Struct RunnableAssign 

pub struct RunnableAssign { /* private fields */ }

A Runnable that adds new key-value pairs to a HashMap<String, Value>.

Each mapping runs a Runnable on the input HashMap and merges the result back into the HashMap under the specified key.

This is the LCEL equivalent of Python’s RunnableAssign.

Implementations

impl RunnableAssign

pub fn new() -> Self

Create an empty assign runnable.

pub fn with<O, R>(self, key: &str, runnable: R) -> Self

where O: Serialize + Send + Sync + 'static, R: Runnable<HashMap<String, Value>, O> + Send + Sync + 'static, R::Error: Into<LcelError>,

Add a mapping that runs the given runnable and stores the result under the specified key.

The runnable takes HashMap<String, Value> as input and produces any output that implements serde::Serialize. The output is serialized to serde_json::Value and merged into the HashMap.

pub fn len(&self) -> usize

Number of mappings.

pub fn is_empty(&self) -> bool

Whether there are no mappings.

Trait Implementations

impl Debug for RunnableAssign

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

Formats the value using the given formatter.

impl Default for RunnableAssign

fn default() -> Self

Returns the “default value” for a type.

impl Runnable<HashMap<String, Value>, HashMap<String, Value>> for RunnableAssign

fn invoke<'life0, 'async_trait>( &'life0 self, input: HashMap<String, Value>, config: Option<RunnableConfig>, ) -> Pin<Box<dyn Future<Output = Result<HashMap<String, Value>, LcelError>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

Execute all mappings and merge results into the input HashMap.

fn stream<'life0, 'async_trait>( &'life0 self, input: HashMap<String, Value>, config: Option<RunnableConfig>, ) -> Pin<Box<dyn Future<Output = Result<Pin<Box<dyn Stream<Item = Result<HashMap<String, Value>, LcelError>> + Send>>, LcelError>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

Stream: invoke and return single-element stream.

fn batch<'life0, 'async_trait>( &'life0 self, inputs: Vec<HashMap<String, Value>>, config: Option<RunnableConfig>, ) -> Pin<Box<dyn Future<Output = Result<Vec<HashMap<String, Value>>, LcelError>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

Batch: invoke per input.

type Error = LcelError

Error type.

fn batch_as_completed<'life0, 'async_trait>( &'life0 self, inputs: Vec<Input>, config: Option<RunnableConfig>, ) -> Pin<Box<dyn Future<Output = Result<Vec<(usize, Output)>, Self::Error>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

Batch processing that returns results in completion order.

fn transform<'life0, 'async_trait>( &'life0 self, input: Pin<Box<dyn Stream<Item = Result<Input, Self::Error>> + Send>>, config: Option<RunnableConfig>, ) -> Pin<Box<dyn Future<Output = Result<Pin<Box<dyn Stream<Item = Result<Output, Self::Error>> + Send>>, Self::Error>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

Stream-to-stream transformation - the core of LCEL streaming.