forked from Archives/langchain
You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
113 lines
3.7 KiB
Python
113 lines
3.7 KiB
Python
"""Dynamic prompt schema definition."""
|
|
import re
|
|
from typing import Any, Callable, Dict, List
|
|
|
|
from pydantic import BaseModel, Extra, root_validator
|
|
|
|
from langchain.prompts.base import DEFAULT_FORMATTER_MAPPING, BasePrompt
|
|
|
|
|
|
class DynamicPrompt(BaseModel, BasePrompt):
|
|
r"""Schema to represent a dynamic prompt for an LLM.
|
|
|
|
Example:
|
|
.. code-block:: python
|
|
|
|
from langchain import DynamicPrompt
|
|
dynamic_prompt = DynamicPrompt(
|
|
examples=["Say hi. Hi", "Say ho. Ho"],
|
|
example_separator="\n\n",
|
|
prefix="",
|
|
suffix="\n\nSay {foo}"
|
|
input_variables=["foo"],
|
|
max_length=200,
|
|
get_text_length=word_count
|
|
)
|
|
"""
|
|
|
|
examples: List[str]
|
|
"""A list of the examples that the prompt template expects."""
|
|
|
|
example_separator: str = "\n\n"
|
|
"""Example separator, e.g. \n\n, for the dynamic prompt creation."""
|
|
|
|
input_variables: List[str] = []
|
|
"""A list of the names of the variables the prompt template expects."""
|
|
|
|
prefix: str = ""
|
|
"""Prefix for the prompt."""
|
|
|
|
suffix: str = ""
|
|
"""Suffix for the prompt."""
|
|
|
|
template_format: str = "f-string"
|
|
"""The format of the prompt template. Options are: 'f-string'."""
|
|
|
|
get_text_length: Callable[[str], int] = lambda x: len(re.split("\n| ", x))
|
|
"""Function to measure prompt length. Defaults to word count."""
|
|
|
|
max_length: int = 2048
|
|
"""Max length for the prompt, beyond which examples are cut."""
|
|
|
|
class Config:
|
|
"""Configuration for this pydantic object."""
|
|
|
|
extra = Extra.forbid
|
|
|
|
def template(self, example_list: List[str], **kwargs: Any) -> str:
|
|
"""Return template given example list."""
|
|
template = self.example_separator.join(
|
|
[self.prefix, *example_list, self.suffix]
|
|
)
|
|
return DEFAULT_FORMATTER_MAPPING[self.template_format](template, **kwargs)
|
|
|
|
def format(self, **kwargs: Any) -> str:
|
|
"""Dynamically format the prompt with the inputs.
|
|
|
|
Args:
|
|
kwargs: Any arguments to be passed to the prompt template.
|
|
|
|
Returns:
|
|
A formatted string.
|
|
|
|
Example:
|
|
|
|
.. code-block:: python
|
|
|
|
prompt.format(variable1="foo")
|
|
"""
|
|
curr_examples = self.examples
|
|
template = self.template(curr_examples, **kwargs)
|
|
while self.get_text_length(template) > self.max_length and curr_examples:
|
|
curr_examples = curr_examples[:-1]
|
|
template = self.template(curr_examples, **kwargs)
|
|
return template
|
|
|
|
@root_validator()
|
|
def template_is_valid(cls, values: Dict) -> Dict:
|
|
"""Check that prefix, suffix and input variables are consistent."""
|
|
input_variables = values["input_variables"]
|
|
prefix = values["prefix"]
|
|
suffix = values["suffix"]
|
|
template_format = values["template_format"]
|
|
if template_format not in DEFAULT_FORMATTER_MAPPING:
|
|
valid_formats = list(DEFAULT_FORMATTER_MAPPING)
|
|
raise ValueError(
|
|
f"Invalid template format. Got `{template_format}`;"
|
|
f" should be one of {valid_formats}"
|
|
)
|
|
try:
|
|
result = values["get_text_length"]("foo")
|
|
assert isinstance(result, int)
|
|
except AssertionError:
|
|
raise ValueError(
|
|
"Invalid text length callable, must take string & return int;"
|
|
)
|
|
dummy_inputs = {input_variable: "foo" for input_variable in input_variables}
|
|
try:
|
|
formatter_func = DEFAULT_FORMATTER_MAPPING[template_format]
|
|
formatter_func(prefix + suffix, **dummy_inputs)
|
|
except KeyError:
|
|
raise ValueError("Invalid prompt schema.")
|
|
return values
|