typedparser

coverage

Typing extension for python argparse using attrs.

Includes typechecking and conversion utilities to parse a dictionary into an attrs instance.

Install

Requires python>=3.8

pip install typedparser

Basic usage

Create an attrs class (decorate with @attr.define). Note that optional arguments must also be typed as optional.
Define and type the fields with typedparser.add_argument - the syntax extends add_argument from argparse.
Parse the args with TypedParser and enjoy args with type hints. Disable typechecking by setting strict=False.

from typing import Optional
from attrs import define
from typedparser import add_argument, TypedParser


@define
class Args:
    # omit the argument name to have it inferred from the field name
    foo: str = add_argument(positional=True)
    bar: int = add_argument(shortcut="-b", type=int, default=0)
    opt: Optional[str] = add_argument()

    # # in case you prefer the regular argparse syntax:
    # foo: str = add_argument("foo")
    # bar: int = add_argument("-b", "--bar", type=int, default=0)
    # opt: Optional[str] = add_argument("--opt")



def main():
    parser = TypedParser.create_parser(Args, strict=True)
    args: Args = parser.parse_args()
    print(args)


if __name__ == "__main__":
    main()

Features

Create commandline arguments with type hints and checks while staying close to the syntax of the standard library's argparse.
Utilities for typechecking and converting nested objects:
- Nested checking and conversion of python standard types
- Supports old and new style typing (e.g. typing.List and list)
- Supports positional and keyword arguments in classes
- Can also typecheck existing attrs instances
- Allows custom conversions, by default converts source type str to target type Path and int to float
- Allows to redefine which objects will be recursed into, by default recurses into standard containers (list, dict, etc.)
- @definenumpy decorator for equality check if the instances contains numpy arrays
Some object utilities in typedparser.objects required for everything else

Advanced usage

Use TypedParser.from_parser(parser, Args) to add typing to an existing parser. This is useful to cover usecases like subparsers or argument groups.
Snippet for argument lists xarg: List[int] = add_argument(shortcut="-x", type=int, action="append", help="Xarg", default=[]), use as -x 1 -x 2 to get [1, 2] in the args instance.

Usage of attr utilities

Define the class hierarchy and parse the input using attrs_from_dict. Use @define(slots=False) to allow multiple inheritance and setting attributes later.

from attrs import define
from typing import Optional
from typedparser import attrs_from_dict

@define
class Cfg:
    foo: int = 12
    bar: Optional[int] = None

print(attrs_from_dict(Cfg, {"foo": 1, "bar": 2}))
# Cfg(foo=1, bar=2)


@define
class CfgNested:
    sub_cfg: Cfg = None

print(attrs_from_dict(CfgNested, {"sub_cfg": {"foo": 1, "bar": 2}}))
# CfgNested(sub_cfg=Cfg(foo=1, bar=2))

Strict mode (default)

Convert everything to the target type, e.g. if the input is a list and the annotation is a tuple, the output will be a tuple
Raise errors if types cannot be matched, there are unknown fields in the input or abstract annotation types are used (e.g. Sequence)
Set _allow_extra_keys = True in the class definition to allow unknown fields in the input

Non-strict mode

Enabled by calling attrs_from_dict with strict=False

No conversion except for creating the attrs instance from the dict
Ignore silently if types cannot be matched or abstract annotation types are used
Unknown fields in the input will be added to the attrs instance if possible (see the hint below about slots)

Skip unknowns

Set skip_unknowns=True to ignore all unknown input fields.

Hints

The following behaviour stems from the attrs package:

New attributes cannot to be added after class definition to an attrs instance, unless it is created with @define(slots=False) Explanation
Untyped fields or "ClassVar" typed fields will be ignored by @attrs.define and therefore also by this library.

Install locally and run tests

Clone repository and cd into. Setup python 3.7 or higher. Note: Some tests are skipped for python 3.7.

pip install -e .
pip install pytest pytest-cov pylint
pylint typedparser

# run tests
python -m pytest --cov
pylint tests

Metadata

Release files for typedparser 0.35.4

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

Source distribution (sdist)

Source distribution for typedparser 0.35.4
File	Size	Uploaded
typedparser-0.35.4.tar.gz	27.1 kB	Oct 3, 2026	Details

Built distribution (wheel)

Table of built distributions (wheels) for typedparser 0.35.4
File	Interpreter	ABI	Platform	Reset
typedparser-0.35.4-py3-none-any.whl 26.6 kB Oct 3, 2026	Python 3	none	any	Details

Total release size: 53.6 kB

Release files / typedparser-0.35.4.tar.gz

Download URL	typedparser-0.35.4.tar.gz
Size	27.1 kB
Tags	Source
SHA-256 checksum How to use checksums	`1864b2a576d08e07c81ba7f0443cd29420a6e087185e3e874360c2c017800a73`
BLAKE2b-256 checksum How to use checksums	`0a866deb1cc8a64cc34eb791485a589150f174d3ce6eeb472d8578aaaf3e5b27`
Upload date	Oct 3, 2026
Uploaded using Trusted Publishing? What is trusted publishing?	No
Uploaded via	`twine/6.2.0 CPython/3.9.23`

Release files / typedparser-0.35.4-py3-none-any.whl

Download URL	typedparser-0.35.4-py3-none-any.whl
Size	26.6 kB
Tags	Python 3
SHA-256 checksum How to use checksums	`29685399397a0beef04214814d9be8fef1e62d1f244909525be35596cac9c3b6`
BLAKE2b-256 checksum How to use checksums	`0c3553d2a2368b27b0752d248b1c44708a9ab63bc49247f7127b7d4c7442a9d5`
Upload date	Oct 3, 2026
Uploaded using Trusted Publishing? What is trusted publishing?	No
Uploaded via	`twine/6.2.0 CPython/3.9.23`