Add basic critique revise template (#12688)

@baskaryan @hwchase17

---------

Co-authored-by: Erick Friis <erick@langchain.dev>

templates/basic-critique-revise/LICENSE

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+MIT License
+
+Copyright (c) 2023 LangChain, Inc.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

templates/basic-critique-revise/README.md

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+# basic-critique-revise
+
+TODO: What does this package do
+
+## Environment Setup
+
+TODO: What environment variables need to be set (if any)
+
+## Usage
+
+To use this package, you should first have the LangChain CLI installed:
+
+```shell
+pip install -U "langchain-cli[serve]"
+```
+
+To create a new LangChain project and install this as the only package, you can do:
+
+```shell
+langchain app new my-app --package basic-critique-revise
+```
+
+If you want to add this to an existing project, you can just run:
+
+```shell
+langchain app add basic-critique-revise
+```
+
+And add the following code to your `server.py` file:
+```python
+from basic_critique_revise import chain as basic_critique_revise_chain
+
+add_routes(app, basic_critique_revise_chain, path="/basic-critique-revise")
+```
+
+(Optional) Let's now configure LangSmith. 
+LangSmith will help us trace, monitor and debug LangChain applications. 
+LangSmith is currently in private beta, you can sign up [here](https://smith.langchain.com/). 
+If you don't have access, you can skip this section
+
+
+```shell
+export LANGCHAIN_TRACING_V2=true
+export LANGCHAIN_API_KEY=<your-api-key>
+export LANGCHAIN_PROJECT=<your-project>  # if not specified, defaults to "default"
+```
+
+If you are inside this directory, then you can spin up a LangServe instance directly by:
+
+```shell
+langchain serve
+```
+
+This will start the FastAPI app with a server is running locally at 
+[http://localhost:8000](http://localhost:8000)
+
+We can see all templates at [http://127.0.0.1:8000/docs](http://127.0.0.1:8000/docs)
+We can access the playground at [http://127.0.0.1:8000/basic-critique-revise/playground](http://127.0.0.1:8000/basic-critique-revise/playground)  
+
+We can access the template from code with:
+
+```python
+from langserve.client import RemoteRunnable
+
+runnable = RemoteRunnable("http://localhost:8000/basic-critique-revise")
+```

templates/basic-critique-revise/basic_critique_revise/__init__.py

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+from basic_critique_revise.chain import chain
+
+__all__ = ["chain"]

templates/basic-critique-revise/basic_critique_revise/chain.py

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+import json
+from datetime import datetime
+from enum import Enum
+from operator import itemgetter
+from typing import Any, Dict, Sequence
+
+from langchain.chains.openai_functions import convert_to_openai_function
+from langchain.chat_models import ChatOpenAI
+from langchain.prompts import ChatPromptTemplate
+from langchain.pydantic_v1 import BaseModel, Field, ValidationError, conint
+from langchain.schema.runnable import (
+    Runnable,
+    RunnableBranch,
+    RunnableLambda,
+    RunnablePassthrough,
+)
+
+
+class TaskType(str, Enum):
+    call = "Call"
+    message = "Message"
+    todo = "Todo"
+    in_person_meeting = "In-Person Meeting"
+    email = "Email"
+    mail = "Mail"
+    text = "Text"
+    open_house = "Open House"
+
+
+class Task(BaseModel):
+    title: str = Field(..., description="The title of the tasks, reminders and alerts")
+    due_date: datetime = Field(
+        ..., description="Due date. Must be a valid ISO date string with timezone"
+    )
+    task_type: TaskType = Field(None, description="The type of task")
+
+
+class Tasks(BaseModel):
+    """JSON definition for creating tasks, reminders and alerts"""
+
+    tasks: Sequence[Task]
+
+
+template = """Respond to the following user query to the best of your ability:
+
+{query}"""
+
+generate_prompt = ChatPromptTemplate.from_template(template)
+
+function_args = {"functions": [convert_to_openai_function(Tasks)]}
+
+task_function_call_model = ChatOpenAI(model="gpt-3.5-turbo").bind(**function_args)
+
+output_parser = RunnableLambda(
+    lambda x: json.loads(
+        x.additional_kwargs.get("function_call", {}).get("arguments", '""')
+    )
+)
+
+
+revise_template = """
+Based on the provided context, fix the incorrect result of the original prompt
+and the provided errors. Only respond with an answer that satisfies the
+constraints laid out in the original prompt and fixes the Pydantic errors.
+
+Hint: Datetime fields must be valid ISO date strings.
+
+<context>
+<original_prompt>
+{original_prompt}
+</original_prompt>
+<incorrect_result>
+{completion}
+</incorrect_result>
+<errors>
+{error}
+</errors>
+</context>"""
+
+revise_prompt = ChatPromptTemplate.from_template(revise_template)
+
+revise_chain = revise_prompt | task_function_call_model | output_parser
+
+
+def output_validator(output):
+    try:
+        Tasks.validate(output["completion"])
+    except ValidationError as e:
+        return str(e)
+
+    return None
+
+
+class IntermediateType(BaseModel):
+    error: str
+    completion: Dict
+    original_prompt: str
+    max_revisions: int
+
+
+validation_step = RunnablePassthrough().assign(error=RunnableLambda(output_validator))
+
+
+def revise_loop(input: IntermediateType) -> IntermediateType:
+    revise_step = RunnablePassthrough().assign(completion=revise_chain)
+
+    else_step: Runnable[IntermediateType, IntermediateType] = RunnableBranch(
+        (lambda x: x["error"] is None, RunnablePassthrough()),
+        revise_step | validation_step,
+    ).with_types(input_type=IntermediateType)
+
+    for _ in range(max(0, input["max_revisions"] - 1)):
+        else_step = RunnableBranch(
+            (lambda x: x["error"] is None, RunnablePassthrough()),
+            revise_step | validation_step | else_step,
+        )
+    return else_step
+
+
+revise_lambda = RunnableLambda(revise_loop)
+
+
+class InputType(BaseModel):
+    query: str
+    max_revisions: conint(ge=1, le=10) = 5
+
+
+chain: Runnable[Any, Any] = (
+    {
+        "original_prompt": generate_prompt,
+        "max_revisions": itemgetter("max_revisions"),
+    }
+    | RunnablePassthrough().assign(
+        completion=(
+            RunnableLambda(itemgetter("original_prompt"))
+            | task_function_call_model
+            | output_parser
+        )
+    )
+    | validation_step
+    | revise_lambda
+    | RunnableLambda(itemgetter("completion"))
+).with_types(input_type=InputType)

templates/basic-critique-revise/pyproject.toml

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+[tool.poetry]
+name = "basic_critique_revise"
+version = "0.0.1"
+description = ""
+authors = []
+readme = "README.md"
+
+[tool.poetry.dependencies]
+python = ">=3.8.1,<4.0"
+langchain = ">=0.0.313, <0.1"
+openai = "^0.28.1"
+
+[tool.poetry.group.dev.dependencies]
+langchain-cli = ">=0.0.15"
+fastapi = "^0.104.0"
+sse-starlette = "^1.6.5"
+
+[tool.langserve]
+export_module = "basic_critique_revise"
+export_attr = "chain"
+
+[build-system]
+requires = ["poetry-core"]
+build-backend = "poetry.core.masonry.api"