semvec/pypi-packages huggingface dataset:
arcparse 1.3.1
Declare program arguments in a type-safe way
License: MIT
Requires Python: <4.0,>=3.12
Keywords: argparse, declarative, argument, parsing, type-safe

# arcparse
Declare program arguments in a type-safe way.

This project builds on top of `argparse` by adding type-safety and allowing a more expressive argument parser definition.

## Example usage
```py
from arcparse import arcparser, flag, positional
from pathlib import Path

@arcparser
class Args:
    path: Path = positional()
    recurse: bool = flag("-r")
    item_limit: int = 100
    output_path: Path | None

args = Args.parse()
print(f"Scanning {args.path}...")
...
```
<details>
    <summary>Help output of this parser</summary>

    usage: program.py [-h] [-r] [--item-limit ITEM_LIMIT] [--output-path OUTPUT_PATH] path

    positional arguments:
    path

    options:
    -h, --help            show this help message and exit
    -r, --recurse
    --item-limit ITEM_LIMIT
    --output-path OUTPUT_PATH

</details>

For more examples see [Examples](examples/).

## Installation
```shell
# Using pip
$ pip install arcparse
```

## Features
- Positional, Option and [Flag](./examples/flag.py) arguments
- Name overriding
- [Multiple values per argument](./examples/multiple.py)
- [Type conversions](./examples/conversion.py)
- [Mutually exclusive groups](./examples/mutual_exclusion.py)
- [Subparsers](./examples/subparsers.py)
- [Parser inheritance](./examples/inheritance.py) (with [overriding](./examples/override.py))
- [Presence validation](./examples/presence_validation.py)

## Credits
This project was inspired by [swansonk14/typed-argument-parser](https://github.com/swansonk14/typed-argument-parser).

## Known issues

### Annotations
`from __future__ import annotations` makes all annotations strings at runtime. This library relies on class variable annotations's types being actual types. `inspect.get_annotations(obj, eval_str=True)` is used to evaluate string annotations to types in order to assign converters. If an argument is annotated with a non-builtin type which is defined outside of the argument-defining class body the type can't be found which results in `NameError`s. This is avoidable either by only using custom types which have been defined in the argument-defining class body (which is restrictive), or alternatively by not using the `annotations` import which should not be necessary from python 3.14 forward thanks to [PEP 649](https://peps.python.org/pep-0649/).