59 lines
1.9 KiB
Python
59 lines
1.9 KiB
Python
from __future__ import annotations
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from typing import Any
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from langchain_core.output_parsers import BaseOutputParser
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from langchain_core.utils import pre_init
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from typing_extensions import override
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_MIN_PARSERS = 2
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class CombiningOutputParser(BaseOutputParser[dict[str, Any]]):
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"""Combine multiple output parsers into one."""
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parsers: list[BaseOutputParser]
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@classmethod
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@override
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def is_lc_serializable(cls) -> bool:
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return True
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@pre_init
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def validate_parsers(cls, values: dict[str, Any]) -> dict[str, Any]:
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"""Validate the parsers."""
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parsers = values["parsers"]
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if len(parsers) < _MIN_PARSERS:
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msg = "Must have at least two parsers"
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raise ValueError(msg)
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for parser in parsers:
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if parser._type == "combining": # noqa: SLF001
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msg = "Cannot nest combining parsers"
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raise ValueError(msg)
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if parser._type == "list": # noqa: SLF001
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msg = "Cannot combine list parsers"
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raise ValueError(msg)
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return values
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@property
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def _type(self) -> str:
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"""Return the type key."""
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return "combining"
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def get_format_instructions(self) -> str:
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"""Instructions on how the LLM output should be formatted."""
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initial = f"For your first output: {self.parsers[0].get_format_instructions()}"
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subsequent = "\n".join(
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f"Complete that output fully. Then produce another output, separated by two newline characters: {p.get_format_instructions()}" # noqa: E501
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for p in self.parsers[1:]
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)
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return f"{initial}\n{subsequent}"
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def parse(self, text: str) -> dict[str, Any]:
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"""Parse the output of an LLM call."""
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texts = text.split("\n\n")
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output = {}
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for txt, parser in zip(texts, self.parsers, strict=False):
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output.update(parser.parse(txt.strip()))
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return output
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