Struct LengthBasedExampleSelector 

pub struct LengthBasedExampleSelector { /* private fields */ }

Selects examples in order until they would no longer fit in max_length, counting the length of the input too. Useful to keep a prompt within the context window.

Length is measured in words by default (see with_length_fn).

let selector = LengthBasedExampleSelector::new(
    template_fstring!("Input: {input}\nOutput: {output}", "input", "output"),
    vec![prompt_args! {"input" => "happy", "output" => "sad"}],
)?
.with_max_length(25);

Implementations

impl LengthBasedExampleSelector

pub const DEFAULT_MAX_LENGTH: usize = 2048

Default max_length, in words.

pub fn new( example_prompt: PromptTemplate, examples: Vec<PromptArgs>, ) -> Result<Self, PromptError>

A selector over examples, formatted with example_prompt to measure them. Fails if an example is missing a variable of example_prompt.

pub fn with_max_length(self, max_length: usize) -> Self

The most the selected examples plus the input may add up to.

pub fn with_length_fn<F>(self, length_fn: F) -> Self

where F: Fn(&str) -> usize + Send + Sync + 'static,

How to measure text, e.g. a tokenizer’s token count. Example lengths are recomputed with it.

Trait Implementations

impl Debug for LengthBasedExampleSelector

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

Formats the value using the given formatter.

impl ExampleSelector for LengthBasedExampleSelector

fn add_example<'life0, 'async_trait>( &'life0 self, example: PromptArgs, ) -> Pin<Box<dyn Future<Output = Result<(), PromptError>> + Send + 'async_trait>>

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

Adds an example to the pool the selector chooses from.

fn select_examples<'life0, 'life1, 'async_trait>( &'life0 self, input_variables: &'life1 PromptArgs, ) -> Pin<Box<dyn Future<Output = Result<Vec<PromptArgs>, PromptError>> + Send + 'async_trait>>

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

The examples to use for input_variables (the prompt’s inputs), in the order they should appear.