Source code for langchain.output_parsers.retry
from __future__ import annotations
from typing import Any, TypeVar
from langchain.prompts.prompt import PromptTemplate
from langchain.schema import (
    BaseOutputParser,
    BasePromptTemplate,
    OutputParserException,
    PromptValue,
)
from langchain.schema.language_model import BaseLanguageModel
NAIVE_COMPLETION_RETRY = """Prompt:
{prompt}
Completion:
{completion}
Above, the Completion did not satisfy the constraints given in the Prompt.
Please try again:"""
NAIVE_COMPLETION_RETRY_WITH_ERROR = """Prompt:
{prompt}
Completion:
{completion}
Above, the Completion did not satisfy the constraints given in the Prompt.
Details: {error}
Please try again:"""
NAIVE_RETRY_PROMPT = PromptTemplate.from_template(NAIVE_COMPLETION_RETRY)
NAIVE_RETRY_WITH_ERROR_PROMPT = PromptTemplate.from_template(
    NAIVE_COMPLETION_RETRY_WITH_ERROR
)
T = TypeVar("T")
[docs]class RetryOutputParser(BaseOutputParser[T]):
    """Wraps a parser and tries to fix parsing errors.
    Does this by passing the original prompt and the completion to another
    LLM, and telling it the completion did not satisfy criteria in the prompt.
    """
    parser: BaseOutputParser[T]
    """The parser to use to parse the output."""
    # Should be an LLMChain but we want to avoid top-level imports from langchain.chains
    retry_chain: Any
    """The LLMChain to use to retry the completion."""
[docs]    @classmethod
    def from_llm(
        cls,
        llm: BaseLanguageModel,
        parser: BaseOutputParser[T],
        prompt: BasePromptTemplate = NAIVE_RETRY_PROMPT,