Skip to main content
Pre-release

This release is a pre-release and may not be stable for production use.

logo

Langfun

PyPI version codecov pytest

Installation | Getting started | Tutorial | Discord community

Introduction

Langfun is a PyGlove powered library that aims to make language models (LM) fun to work with. Its central principle is to enable seamless integration between natural language and programming by treating language as functions. Through the introduction of Object-Oriented Prompting, Langfun empowers users to prompt LLMs using objects and types, offering enhanced control and simplifying agent development.

To unlock the magic of Langfun, you can start with Langfun 101. Notably, Langfun is compatible with popular LLMs such as Gemini, GPT, Claude, all without the need for additional fine-tuning.

Why Langfun?

Langfun is powerful and scalable:

  • Seamless integration between natural language and computer programs.
  • Modular prompts, which allows a natural blend of texts and modalities;
  • Efficient for both request-based workflows and batch jobs;
  • A powerful eval framework that thrives dimension explosions.

Langfun is simple and elegant:

  • An intuitive programming model, graspable in 5 minutes;
  • Plug-and-play into any Python codebase, making an immediate difference;
  • Comprehensive LLMs under a unified API: Gemini, GPT, Claude, Llama3, and more.
  • Designed for agile developement: offering intellisense, easy debugging, with minimal overhead;

Hello, Langfun

import langfun as lf
import pyglove as pg

from IPython import display

class Item(pg.Object):
  name: str
  color: str

class ImageDescription(pg.Object):
  items: list[Item]

image = lf.Image.from_uri('https://upload.wikimedia.org/wikipedia/commons/thumb/8/83/Solar_system.jpg/1646px-Solar_system.jpg')
display.display(image)

desc = lf.query(
    'Describe objects in {{my_image}} from top to bottom.',
    ImageDescription,
    lm=lf.llms.Gpt4o(api_key='<your-openai-api-key>'),
    my_image=image,
)
print(desc)

Output:

my_image

ImageDescription(
  items = [
    0 : Item(
      name = 'Mercury',
      color = 'Gray'
    ),
    1 : Item(
      name = 'Venus',
      color = 'Yellow'
    ),
    2 : Item(
      name = 'Earth',
      color = 'Blue and white'
    ),
    3 : Item(
      name = 'Moon',
      color = 'Gray'
    ),
    4 : Item(
      name = 'Mars',
      color = 'Red'
    ),
    5 : Item(
      name = 'Jupiter',
      color = 'Brown and white'
    ),
    6 : Item(
      name = 'Saturn',
      color = 'Yellowish-brown with rings'
    ),
    7 : Item(
      name = 'Uranus',
      color = 'Light blue'
    ),
    8 : Item(
      name = 'Neptune',
      color = 'Dark blue'
    )
  ]
)

See Langfun 101 for more examples.

Install

Langfun offers a range of features through Extras, allowing users to install only what they need. The minimal installation of Langfun requires only PyGlove, Jinja2, and requests. To install Langfun with its minimal dependencies, use:

pip install langfun

For a complete installation with all dependencies, use:

pip install langfun[all]

To install a nightly build, include the --pre flag, like this:

pip install langfun[all] --pre

If you want to customize your installation, you can select specific features using package names like langfun[X1, X2, ..., Xn], where Xi corresponds to a tag from the list below:

Tag Description
all All Langfun features.
vertexai VertexAI access.
mime All MIME supports.
mime-pil Image support for PIL.
ui UI enhancements

For example, to install a nightly build that includes VertexAI access, full modality support, and UI enhancements, use:

pip install langfun[vertexai,mime,ui] --pre

Disclaimer: this is not an officially supported Google product.

Metadata

Release files for langfun 0.1.2.dev202507300805

For a detailed explanation of source distributions (sdists) and built distributions (wheels), please see the package formats documentation.

Source distribution (sdist)

Source distribution for langfun 0.1.2.dev202507300805
File Size Uploaded
langfun-0.1.2.dev202507300805.tar.gz 294.3 kB Details

Built distribution (wheel)

Table of built distributions (wheels) for langfun 0.1.2.dev202507300805
File Interpreter ABI Platform
langfun-0.1.2.dev202507300805-py3-none-any.whl Python 3 none any Details

Total release size: 712.2 kB

Release files / langfun-0.1.2.dev202507300805.tar.gz

Download URL langfun-0.1.2.dev202507300805.tar.gz
Size 294.3 kB
Tags Source
SHA-256 checksum
How to use checksums
355acc154450e525075365c6030a3cfa1c8d0967f03bc81d0cb546361eef890a
BLAKE2b-256 checksum
How to use checksums
b28752aa204e320be11fb98547ca13d84b68491830507648288b42b207b44298
Upload date
Uploaded using Trusted Publishing?
What is trusted publishing?
No
Uploaded via twine/6.1.0 CPython/3.13.5

Release files / langfun-0.1.2.dev202507300805-py3-none-any.whl

Download URL langfun-0.1.2.dev202507300805-py3-none-any.whl
Size 417.9 kB
Tags Python 3
SHA-256 checksum
How to use checksums
1b47fb61ed13a6a1442c47bad96428301c7edd933cc867d9b8f0a89849f6db07
BLAKE2b-256 checksum
How to use checksums
93530c85c718effabb08c956a770f84b9af3106931f171ede79f044f6abe8a8f
Upload date
Uploaded using Trusted Publishing?
What is trusted publishing?
No
Uploaded via twine/6.1.0 CPython/3.13.5

Release history Release notifications | RSS feed

This release

0.1.1

2 release files

0.1.0

2 release files

0.0.1

2 release files

Anthropic, PBC Visionary sponsor Bloomberg Visionary sponsor Hudson River Trading Visionary sponsor Meta Visionary sponsor NVIDIA Visionary sponsor Microsoft Sustainability sponsor Depot Continuous Integration AWS Cloud computing and Security Sponsor Datadog Monitoring Fastly CDN Google Download Analytics Sentry Error logging StatusPage Status page