Struct ChatPromptTemplate 

pub struct ChatPromptTemplate { /* private fields */ }

A chat prompt template that renders a sequence of messages.

let prompt = ChatPromptTemplate::from_messages(vec![
    MessageTemplate::System(PromptTemplate::new("You are a helpful assistant.")),
    MessageTemplate::Placeholder("history".to_string()),
    MessageTemplate::Human(PromptTemplate::new("{{ input }}")),
]);

Implementations

impl ChatPromptTemplate

pub fn new(templates: Vec<MessageTemplate>) -> Self

pub fn from_messages(templates: Vec<MessageTemplate>) -> Self

Alias for new, matching LangChain’s factory method name.

pub fn format( &self, values: &HashMap<String, Value>, ) -> Result<Vec<Message>, SynapticError>

Render the templates against the given variables, producing a list of messages.

Trait Implementations

impl Runnable<HashMap<String, Value>, Vec<Message>> for ChatPromptTemplate

fn invoke<'life0, 'life1, 'async_trait>( &'life0 self, input: HashMap<String, Value>, _config: &'life1 RunnableConfig, ) -> Pin<Box<dyn Future<Output = Result<Vec<Message>, SynapticError>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Execute this runnable on a single input.

fn batch<'life0, 'life1, 'async_trait>( &'life0 self, inputs: Vec<I>, config: &'life1 RunnableConfig, ) -> Pin<Box<dyn Future<Output = Vec<Result<O, SynapticError>>> + Send + 'async_trait>>

where 'life0: 'async_trait, 'life1: 'async_trait, Self: 'async_trait,

Execute this runnable on multiple inputs sequentially.

fn stream<'a>( &'a self, input: I, config: &'a RunnableConfig, ) -> Pin<Box<dyn Stream<Item = Result<O, SynapticError>> + Send + 'a>>

where I: 'a,

Stream the output. Default wraps invoke as a single-item stream. Override for true streaming (e.g., token-by-token from an LLM).

fn boxed(self) -> BoxRunnable<I, O>

where Self: Sized + 'static,

Wrap this runnable into a type-erased BoxRunnable for composition via |.