File size: 2,827 Bytes
1856027 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 | # -*- coding: utf-8 -*-
# Copyright 2024 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
import string
from typing import Set
class PromptTemplate:
"""A prompt template for creating prompts with variables.
The `PromptTemplate` class allows users to define a template string with
variables represented in curly braces `{variable}`. The variable
names cannot contain spaces. These variables can be replaced with specific
values using the `assemble` method, providing flexibility in generating
dynamic prompts.
Usage:
```
template_str = "Hello, {name}! Today is {day}. How are you?"
prompt_template = PromptTemplate(template_str)
completed_prompt = prompt_template.assemble(name="John", day="Monday")
print(completed_prompt)
```
"""
def __init__(self, template: str):
"""Initializes the PromptTemplate with a given template.
Args:
template: The template string with variables. Variables should be
represented in curly braces `{variable}`.
"""
self.template = str(template)
self.variables = self._get_variables()
def _get_variables(self) -> Set[str]:
"""Extracts and return a set of variable names from the template."""
return set(
field_name
for _, field_name, _, _ in string.Formatter().parse(self.template)
if field_name is not None
)
def assemble(self, **kwargs) -> "PromptTemplate":
"""Replaces only the provided variables in the template with specific values.
Args:
**kwargs: Keyword arguments where keys are placeholder names and values
are the replacements.
Returns:
A new PromptTemplate instance with the updated template string.
"""
replaced_values = {
key: kwargs.get(key, "{" + key + "}") for key in self.variables
}
new_template = self.template.format(**replaced_values)
return PromptTemplate(new_template)
def __str__(self) -> str:
"""Returns the template string."""
return self.template
def __repr__(self) -> str:
"""Returns a string representation of the PromptTemplate."""
return f"PromptTemplate('{self.template}')"
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