ArgTyper

– ArgumentParser on Typehints and Decorators

ArgTyper provides and overlay for argparse.ArgumentParser to create parsers based on function type hint information enhanced with information provided by function decorators.

Additionally argtyper supports handling of async coroutines as well as normal functions.

Quickstart

In it’s simplest form, usage of ArgTyper looks as follows:

import argtyper


async def hello(name: str, amount: int = 2):
    print("\n".join([f"Hello {name.upper()}"] * amount))


at = argtyper.ArgTyper(hello)
at()

Assuming the Python code above is saved into a file called simple.py, it can be run at the command line and provides useful help messages:

$ python simple.py -h
usage: simple.py [-h] [--amount AMOUNT] NAME

positional arguments:
  NAME             provide argument of type STR

optional arguments:
  -h, --help       show this help message and exit
  --amount AMOUNT  provide argument of type INT

When run with the appropriate arguments it looks like the following:

$ python simple.py Yoda
Hello YODA
Hello YODA

$ python simple.py Yoda --amount 4
Hello YODA
Hello YODA
Hello YODA
Hello YODA

If invalid arguments are passed in, it will issue an error:

$ python simple.py Yoda --amount z
usage: simple.py [-h] [--amount AMOUNT] NAME

Error: simple.py: argument --amount: invalid int value: 'z'

For a more in-depth look on what ArgTyper can do for you, take a look at the following chapters.

Introduction

• Basic Usage
  • Command
  • Argument
  • SubCommand
  • SubParser
  • ArgumentGroup
  • MutuallyExclusiveArgumentGroup
  • Conclusion
• Additional Features
  • Responses
  • Wrapping external methods
  • Subcommands & Instance Methods
  • Parents=
  • Extend the Parser
• Supported Type Annotations
  • Standard Types
  • Lists
  • Tuples
  • Literals
  • Custom Arguments
  • Custom Actions

Known Limitations

• custom argparse.Actions do not support async mode. If you use custom actions while calling the parser in async mode, those can potentially block the event loop for other tasks. This shouldn’t be a problem if they are not performing any I/O bound operations, though.

Module Objects

• ArgTyper
• Decorators
• Exceptions

Indices and tables

• Index

• Module Index

• Search Page