Metadata-Version: 2.4
Name: uncalled-for
Version: 0.4.0
Summary: Async dependency injection for Python functions
Project-URL: Repository, https://github.com/chrisguidry/uncalled-for
Project-URL: Bug Tracker, https://github.com/chrisguidry/uncalled-for/issues
Author-email: Chris Guidry <guid@omg.lol>
License: # Released under MIT License
        
        Copyright (c) 2025 Chris Guidry.
        
        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.
License-File: LICENSE
Classifier: Development Status :: 3 - Alpha
Classifier: License :: OSI Approved :: MIT License
Classifier: Operating System :: OS Independent
Classifier: Programming Language :: Python :: 3
Classifier: Programming Language :: Python :: 3.10
Classifier: Programming Language :: Python :: 3.11
Classifier: Programming Language :: Python :: 3.12
Classifier: Programming Language :: Python :: 3.13
Classifier: Programming Language :: Python :: 3.14
Classifier: Typing :: Typed
Requires-Python: >=3.10
Description-Content-Type: text/markdown

# uncalled-for

Async dependency injection for Python functions.

Declare what your function needs as parameter defaults. They show up resolved
when the function runs. No ceremony, no container, no configuration.

```python
from uncalled_for import Depends

async def get_db():
    db = await connect()
    try:
        yield db
    finally:
        await db.close()

async def handle_request(db: Connection = Depends(get_db)):
    await db.execute("SELECT 1")
```

## Features

- **Zero dependencies** — standard library only
- **Async-native** — built on `AsyncExitStack` and `ContextVar`
- **Context manager lifecycle** — sync and async generators get proper cleanup
- **Nested dependencies** — dependencies can depend on other dependencies
- **Caching** — each dependency resolves once per call, even if referenced multiple times
- **Call arguments** — a factory can reference the arguments of the call it serves

## Call arguments

A factory sometimes needs a value from the call itself, not from another
dependency. `CallArgument` declares that reference:

```python
from uncalled_for import CallArgument, Depends

def load_user(user_id: str = CallArgument()) -> User:
    return users[user_id]

async def handle_request(
    user_id: str,
    user: User = Depends(load_user),
):
    ...
```

The bare form takes the name of the parameter it is declared on.
`CallArgument("name")` names a different parameter of the outer function. The
reference sees the same value the outer function receives, whether the caller
passed it or another dependency on the outer signature produced it.
`CallArgument(optional=True)` yields `None` when the outer function has no
such argument. References that form a cycle raise `CycleError`.

## Bindings

`Depends` accepts keyword bindings, so you can wire up an ordinary function
without changing it:

```python
async def handle_request(
    user_id: str,
    user: User = Depends(load_user, user_id=CallArgument("user_id")),
):
    ...
```

A binding that is a `Dependency`, such as `CallArgument(...)` or another
`Depends(...)`, resolves first and the factory receives its value. Any other
value passes through as it is. A binding replaces the factory parameter's own
default, which is then never resolved. Two dependencies on the same factory
share one cached result only when their bindings match.

## Install

```
pip install uncalled-for
```
