Python Type Checking with Command Line Inputs

pluralize.py

from sys import argv
from typing import TypeAlias, Literal, Union, get_args


singular_word: TypeAlias = Literal["pie", "pastry"]
plural_word: TypeAlias = Literal["pies", "pastries"]


def pluralize(word: singular_word, quantity: int) -> str:
    plural_map: dict = dict(zip(get_args(singular_word), get_args(plural_word)))

    return f"{quantity} {plural_map[word] if quantity != 1 else word}"


raw_word: Union[singular_word, str] = argv[1]
raw_num: str = argv[2]

if raw_word in get_args(singular_word):
    processed_word: singular_word = raw_word
    processed_num: int = int(raw_num)
    print(pluralize(processed_word, processed_num))
else:
    raise ValueError("Unknown word requested for pluralization")

pluralize_namespace_typing.py

from argparse import ArgumentParser, Namespace
from typing import TypeAlias, Literal, get_args


SingularWord: TypeAlias = Literal["pie", "pastry"]
PluralWord: TypeAlias = Literal["pies", "pastries"]


class PluralizeNamespace(Namespace):
    word: SingularWord
    quantity: int


def pluralize(word: SingularWord, quantity: int) -> str:
    plural_map: dict = dict(zip(get_args(SingularWord), get_args(PluralWord)))

    return f"{quantity} {plural_map[word] if quantity != 1 else word}"


parser: ArgumentParser = ArgumentParser(
    description="Converts a word and quantity to plural statement"
)

parser.add_argument("word", choices=get_args(SingularWord))
parser.add_argument("quantity", type=int)

arguments = parser.parse_args(namespace=PluralizeNamespace)
word_: SingularWord = arguments.word
quantity_: int = arguments.quantity

plural_statement: str = pluralize(word_, quantity_)
print(plural_statement)

pluralize_with_argparse.py

from argparse import ArgumentParser
from typing import TypeAlias, Literal, get_args


SingularWord: TypeAlias = Literal["pie", "pastry"]
PluralWord: TypeAlias = Literal["pies", "pastries"]


def pluralize(word: SingularWord, quantity: int) -> str:
    plural_map: dict = dict(zip(get_args(SingularWord), get_args(PluralWord)))

    return f"{quantity} {plural_map[word] if quantity != 1 else word}"


parser: ArgumentParser = ArgumentParser(
    description="Converts a word and quantity to plural statement"
)

parser.add_argument("word", choices=get_args(SingularWord))
parser.add_argument("quantity", type=int)

arguments = parser.parse_args()
word_: SingularWord = arguments.word
quantity_: int = arguments.quantity

plural_statement: str = pluralize(word_, quantity_)
print(plural_statement)