valid8r.integrations.argparse

argparse integration for valid8r parsers.

This module provides type_from_parser to convert valid8r parsers into argparse-compatible type functions that can be used with ArgumentParser.add_argument().

argparse’s type parameter expects a callable that takes a string and either returns a converted value (on success) or raises TypeError or ValueError (on failure).

Examples

Basic usage with email parser:

import argparse
from valid8r.core import parsers
from valid8r.integrations.argparse import type_from_parser

parser = argparse.ArgumentParser()
parser.add_argument(
    '--email',
    type=type_from_parser(parsers.parse_email),
    help='Email address'
)

With chained validators for port validation:

from valid8r.core import parsers, validators
from valid8r.integrations.argparse import type_from_parser

def port_parser(text):
    return parsers.parse_int(text).bind(
        validators.minimum(1) & validators.maximum(65535)
    )
parser = argparse.ArgumentParser()
parser.add_argument(
    '--port',
    type=type_from_parser(port_parser),
    help='Port number (1-65535)'
)

Functions

type_from_parser(parser)

Convert a valid8r parser into an argparse-compatible type function.

Module Contents

valid8r.integrations.argparse.type_from_parser(parser)

Convert a valid8r parser into an argparse-compatible type function.

Creates a callable that can be used as the ‘type’ parameter in ArgumentParser.add_argument(). The returned function takes a string, parses it using the provided valid8r parser, and either returns the successfully parsed value or raises ValueError with the error message.

Parameters:

parser (collections.abc.Callable[[str | None], valid8r.core.maybe.Maybe[T]]) – A valid8r parser function that takes a string and returns Maybe[T]

Returns:

A callable suitable for use with argparse’s ‘type’ parameter

Raises:

ValueError – When the parser returns a Failure (invalid input)

Return type:

collections.abc.Callable[[str], T]

Examples

>>> from valid8r.core import parsers
>>> from valid8r.integrations.argparse import type_from_parser
>>>
>>> # Create an argparse type for email validation
>>> email_type = type_from_parser(parsers.parse_email)
>>> email = email_type('alice@example.com')
>>> email.local
'alice'
>>>
>>> # Invalid input raises ValueError
>>> try:
...     email_type('not-an-email')
... except ValueError as e:
...     print('Error:', e)
Error: ...