Files
langchain-python/langchain/agents/react/output_parser.py
T
Sunish Sheth 812e5f43f5 Add _type for all parsers (#4189)
Used for serialization. Also add test that recurses through
our subclasses to check they have them implemented

Would fix https://github.com/hwchase17/langchain/issues/3217
Blocking: https://github.com/mlflow/mlflow/pull/8297

---------

Signed-off-by: Sunish Sheth <sunishsheth2009@gmail.com>
Co-authored-by: Dev 2049 <dev.dev2049@gmail.com>
2023-05-11 01:27:58 -07:00

31 lines
1.1 KiB
Python

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