Source code for langchain_core.prompts.message

"""Message prompt templates."""

from __future__ import annotations

from abc import ABC, abstractmethod
from typing import TYPE_CHECKING, Any

from langchain_core.load import Serializable
from langchain_core.messages import BaseMessage
from langchain_core.utils.interactive_env import is_interactive_env

if TYPE_CHECKING:
    from langchain_core.prompts.chat import ChatPromptTemplate




class BaseMessagePromptTemplate(Serializable, ABC):
    """Base class for message prompt templates."""

    @classmethod
    def is_lc_serializable(cls) -> bool:
        """Return whether or not the class is serializable.

        Returns: True.
        """
        return True

    @classmethod
    def get_lc_namespace(cls) -> list[str]:
        """Get the namespace of the langchain object.

        Default namespace is ["langchain", "prompts", "chat"].
        """
        return ["langchain", "prompts", "chat"]



    @abstractmethod
    def format_messages(self, **kwargs: Any) -> list[BaseMessage]:
        """Format messages from kwargs. Should return a list of BaseMessages.

        Args:
            **kwargs: Keyword arguments to use for formatting.

        Returns:
            List of BaseMessages.
        """




    async def aformat_messages(self, **kwargs: Any) -> list[BaseMessage]:
        """Async format messages from kwargs.

        Args:
            **kwargs: Keyword arguments to use for formatting.

        Returns:
            List of BaseMessages.
        """
        return self.format_messages(**kwargs)


    @property
    @abstractmethod
    def input_variables(self) -> list[str]:
        """Input variables for this prompt template.

        Returns:
            List of input variables.
        """



    def pretty_repr(
        self,
        html: bool = False,  # noqa: FBT001,FBT002
    ) -> str:
        """Human-readable representation.

        Args:
            html: Whether to format as HTML. Defaults to False.

        Returns:
            Human-readable representation.
        """
        raise NotImplementedError




    def pretty_print(self) -> None:
        """Print a human-readable representation."""
        print(self.pretty_repr(html=is_interactive_env()))  # noqa: T201


    def __add__(self, other: Any) -> ChatPromptTemplate:
        """Combine two prompt templates.

        Args:
            other: Another prompt template.

        Returns:
            Combined prompt template.
        """
        from langchain_core.prompts.chat import ChatPromptTemplate

        prompt = ChatPromptTemplate(messages=[self])
        return prompt + other