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25 lines
1001 B
Python
25 lines
1001 B
Python
import re
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from typing import Union
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from langchain.agents.agent import AgentOutputParser
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from langchain.schema import AgentAction, AgentFinish
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class ReActOutputParser(AgentOutputParser):
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def parse(self, text: str) -> Union[AgentAction, AgentFinish]:
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action_prefix = "Action: "
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if not text.strip().split("\n")[-1].startswith(action_prefix):
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raise ValueError(f"Could not parse LLM Output: {text}")
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action_block = text.strip().split("\n")[-1]
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action_str = action_block[len(action_prefix) :]
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# Parse out the action and the directive.
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re_matches = re.search(r"(.*?)\[(.*?)\]", action_str)
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if re_matches is None:
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raise ValueError(f"Could not parse action directive: {action_str}")
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action, action_input = re_matches.group(1), re_matches.group(2)
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if action == "Finish":
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return AgentFinish({"output": action_input}, text)
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else:
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return AgentAction(action, action_input, text)
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