LangChain
v0.1.0

View Source LangChain.MessageDelta (LangChain v0.1.0)

Models a "delta" message from a chat LLM. A delta is a small chunk, or piece of a much larger complete message. A series of deltas can are used to construct a complete message.

Delta messages must be applied in order for them to be valid. Delta messages can be combined and transformed into a LangChain.Message once the final piece is received.

Roles

  • :unknown - The role data is missing for the delta.
  • :assistant - Responses coming back from the LLM.

Function calling

  • :function_name - A message from the LLM expressing the intent to execute a function that was previously declared available to it.

    The arguments will eventually be parsed from JSON. However, as deltas are streamed, the arguments come in as text. Once it is fully received it can be parsed as JSON, but it cannot be used before it is complete as it will not be valid JSON.

Summary

Types

t()

Functions

merge_delta(primary, delta_part)

Merge two MessageDelta structs. The first MessageDelta is the primary one that smaller deltas are merged into.

new(attrs \\ %{})

Create a new MessageDelta that represents a message chunk.

new!(attrs \\ %{})

Create a new MessageDelta that represents a message chunk and return it or raise an error if invalid.

to_message(delta)

Convert the MessageDelta to a Message. Can only convert a fully complete MessageDelta.

Types

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t()

View Source 
@type t() :: %LangChain.MessageDelta{
  arguments: term(),
  content: term(),
  function_name: term(),
  index: term(),
  role: term(),
  status: term()
}

Functions

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merge_delta(primary, delta_part)

View Source 
@spec merge_delta(t(), t()) :: t()

Merge two MessageDelta structs. The first MessageDelta is the primary one that smaller deltas are merged into.

iex> delta_1 =
...>   %LangChain.MessageDelta{
...>     content: nil,
...>     index: 0,
...>     function_name: nil,
...>     role: :assistant,
...>     arguments: nil,
...>     status: :incomplete
...>   }
iex> delta_2 =
...>   %LangChain.MessageDelta{
...>     content: "Hello",
...>     index: 0,
...>     function_name: nil,
...>     role: :unknown,
...>     arguments: nil,
...>     status: :incomplete
...>   }
iex> LangChain.MessageDelta.merge_delta(delta_1, delta_2)
%LangChain.MessageDelta{content: "Hello", status: :incomplete, index: 0, function_name: nil, role: :assistant, arguments: nil}

A set of deltas can be easily merged like this:

[first | rest] = list_of_delta_message

Enum.reduce(rest, first, fn new_delta, acc ->
  MessageDelta.merge_delta(acc, new_delta)
end)
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new(attrs \\ %{})

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@spec new(attrs :: map()) :: {:ok, t()} | {:error, Ecto.Changeset.t()}

Create a new MessageDelta that represents a message chunk.

Link to this function

new!(attrs \\ %{})

View Source 
@spec new!(attrs :: map()) :: t() | no_return()

Create a new MessageDelta that represents a message chunk and return it or raise an error if invalid.

Link to this function

to_message(delta)

View Source 
@spec to_message(t()) :: {:ok, LangChain.Message.t()} | {:error, String.t()}

Convert the MessageDelta to a Message. Can only convert a fully complete MessageDelta.

This is assumed to be the result of merging all the received MessageDeltas. An error is returned if the status is :incomplete.

If the MessageDelta fails to convert to a LangChain.Message, an error is returned with the reason.