starflow/transform

Types

Parser

A function that updates the chain’s state based on the model’s response. This allows for custom processing of the model’s output and updating the state accordingly.

Examples

let update_game = fn(state, response) {
  // Extract guess from response
  let guess = parse_guess(response.content)
  // Update game state with new guess
  state.State(..state, guesses: [guess, ..state.guesses])
}

let accumulate_summary = fn(state, response) {
  // Add response to list of summaries
  state.State(..state, summaries: [response.content, ..state.summaries])
}

pub type Parser(any) =
  fn(
    state.State(any),
    state.Response,
    List(#(String, tool.ToolResult)),
  ) ->
    state.State(any)

Prompt

</>

A function that transforms the chain’s state into a list of content blocks that will be sent to the model as a prompt.

Examples

let simple_prompt = fn(state) {
  [state.TextContent("Hello!")]
}

let template_prompt = fn(data: TemplateData) {
  [state.TextContent("User name: " <> data.name)]
}

pub type Prompt(any) =
  fn(state.State(any)) -> List(state.Content)

Functions

parser_default

</>

pub fn parser_default(
  state: State(a),
  last_response: Response,
  tool_results: List(#(String, ToolResult)),
) -> State(a)

Default parser transformer function that:

Preserves the message history by appending the model’s response
Updates the usage information
Maintains the existing state

This is useful when you just want to accumulate the conversation history without any special processing of the responses.

Examples

let flow =
  starflow.new(model)
  |> starflow.with_parser(parser_default)

// Each response will be added to the message history
// and usage stats will be updated

prompt_default

</>

pub fn prompt_default(state: State(a)) -> List(Content)

Default prompt transformer that simply inspects the state and wraps it in a TextContent block.

Examples

let state = "Hello"
prompt_default(state)  // Returns [TextContent("\"Hello\"")]

let state = 42
prompt_default(state)  // Returns [TextContent("42")]