money.amount

def money(minor: int, currency: str) -> Money

@dataclass(frozen=True)
class Money:
    """A monetary amount in integer minor units, tagged with its currency."""

    #: pence, cents, yen; never a float
    minor: int
    #: ISO 4217 alphabetic code, uppercase
    currency: str

from fune.money.amount import money  # money.amount@^1

import re


# Money is declared in function.fune: integer minor units, never a float.
from .money_amount_types import Money

CURRENCY = re.compile(r"[A-Z]{3}")


def money(minor: int, currency: str) -> Money:
    if isinstance(minor, bool) or not isinstance(minor, int):
        raise TypeError("money() takes integer minor units, received %r" % (minor,))
    if not isinstance(currency, str) or not CURRENCY.fullmatch(currency):
        raise ValueError('"%s" is not an uppercase ISO 4217 currency code' % (currency,))
    return Money(minor=minor, currency=currency)


def is_money(value: object) -> bool:
    return isinstance(value, Money)


def assert_same_currency(a: Money, b: Money) -> None:
    """Guard against the silent nonsense of adding GBP to EUR."""
    if a.currency != b.currency:
        raise ValueError("currency mismatch: %s and %s" % (a.currency, b.currency))


def zero(currency: str) -> Money:
    return money(0, currency)

Install

fune build

With that line in your source, in a Python project (language python in fune.project), fune build resolves it and nothing else, pins them in fune.lock, downloads only the Python package of each, and builds the code above into your project’s .fune/build, one readable file per capability with a header linking back here. Or pin a range in fune.project and build in one step:

fune add money.amount

The manifest, vectors and README with only the Python implementation. Install it without the registry with fune add ./money.amount-1.0.2-python.fune, or fetch it from a terminal with fune pull money.amount@1.0.2:python.

The whole function, every language, is one file too: money.amount-1.0.2.fune, 8,117 bytes, sha256 b8ba6ab0ede8ca6006c44677a6da9c5d26f31ea497f0dbc75bfc7587ddc0ab66. It installs into a project of any language.

# fune: before money.amount

# fune: after money.amount

# fune: step money.amount after <n|label>

More from the author

1.0.1 adds tests; behaviour unchanged.

1.0.2 fixes Python accepting a trailing newline in currency; adds tests.

Files