Struct StrOutputParser 

pub struct StrOutputParser { /* private fields */ }

Extract text content from model outputs as a string.

Converts model outputs (such as AIMessage or AIMessageChunk objects) into plain text strings. It’s the simplest output parser and is useful when you need string responses for downstream processing, display, or storage.

Supports streaming, yielding text chunks as they’re generated by the model.

Example

use agent_chain_core::output_parsers::StrOutputParser;

let parser = StrOutputParser::new();

// Parse a simple string
let result = parser.parse("Hello, world!").unwrap();
assert_eq!(result, "Hello, world!");

Implementations

impl StrOutputParser

pub fn new() -> Self

Create a new StrOutputParser.

pub fn is_lc_serializable() -> bool

Returns true as this class is serializable.

pub fn get_lc_namespace() -> Vec<&'static str>

Get the namespace of the LangChain object.

Returns ["langchain", "schema", "output_parser"]

Trait Implementations

impl BaseOutputParser for StrOutputParser

fn parse(&self, text: &str) -> Result<String>

Returns the input text with no changes.

fn parser_type(&self) -> &str

Return the output parser type for serialization.

type Output = String

The output type of this parser.

fn aparse<'life0, 'life1, 'async_trait>( &'life0 self, text: &'life1 str, ) -> Pin<Box<dyn Future<Output = Result<Self::Output>> + Send + 'async_trait>>

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

Async parse a single string model output into some structure.

fn parse_result( &self, result: &[Generation], _partial: bool, ) -> Result<Self::Output>

Parse a list of candidate model Generation objects into a specific format.

fn aparse_result<'life0, 'life1, 'async_trait>( &'life0 self, result: &'life1 [Generation], partial: bool, ) -> Pin<Box<dyn Future<Output = Result<Self::Output>> + Send + 'async_trait>>

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

Async parse a list of candidate model Generation objects into a specific format.

fn parse_with_prompt( &self, completion: &str, _prompt: &dyn PromptValue, ) -> Result<Self::Output>

Parse the output of an LLM call with the input prompt for context.

fn get_format_instructions(&self) -> Result<String>

Instructions on how the LLM output should be formatted.

fn invoke( &self, input: BaseMessage, _config: Option<RunnableConfig>, ) -> Result<Self::Output>

Invoke the parser on input.

fn ainvoke<'life0, 'async_trait>( &'life0 self, input: BaseMessage, config: Option<RunnableConfig>, ) -> Pin<Box<dyn Future<Output = Result<Self::Output>> + Send + 'async_trait>>

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

Async invoke the parser on input.

impl BaseTransformOutputParser for StrOutputParser

fn parse_generation(&self, generation: &Generation) -> Result<Self::Output>

Parse a generation into the output type.

fn transform<'a>( &'a self, input: BoxStream<'a, StringOrMessage>, ) -> BoxStream<'a, Result<Self::Output>>

where Self::Output: 'a,

Transform an input stream into an output stream.

fn atransform<'a>( &'a self, input: BoxStream<'a, StringOrMessage>, ) -> BoxStream<'a, Result<Self::Output>>

where Self::Output: 'a,

Async transform an input stream into an output stream.

impl Clone for StrOutputParser

fn clone(&self) -> StrOutputParser

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for StrOutputParser

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

Formats the value using the given formatter.

impl Default for StrOutputParser

fn default() -> StrOutputParser

Returns the “default value” for a type.

impl Serializable for StrOutputParser

fn is_lc_serializable() -> bool

where Self: Sized,

Is this class serializable?

fn get_lc_namespace() -> Vec<String>

where Self: Sized,

Get the namespace of the LangChain object.

fn to_json(&self) -> Serialized

where Self: Sized + Serialize,

Serialize this object to JSON.

fn lc_secrets(&self) -> HashMap<String, String>

A map of constructor argument names to secret ids.

fn lc_attributes(&self) -> HashMap<String, Value>

List of attribute names that should be included in the serialized kwargs.

fn lc_id() -> Vec<String>

where Self: Sized,

Return a unique identifier for this class for serialization purposes.

fn lc_type_name(&self) -> &'static str

Get the type name of this object.

fn to_json_not_implemented(&self) -> Serialized

Serialize a “not implemented” object.

impl Serialize for StrOutputParser

fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>

where S: Serializer,

Serialize this value into the given Serde serializer.