@wads.dev/i18n-py

Framework-independent Python foundations for strongly typed internationalization.

i18n-py gives Python projects typed translation contracts, deferred string and message references, RFC-compliant Accept-Language negotiation and request-scoped resolvers. It has zero runtime dependencies and no framework lock-in.

⚠️ Status: 0.0.1-alpha. Esta versão é um pré-lançamento alfa experimental (super-alpha). Contratos públicos, nomes de classes e métodos ainda sofrerão alterações antes da versão estável 1.0.0.

Wads.dev i18n ecosystem

Why it exists

Translation files are application code: their structure changes, keys move, languages grow, and mistakes should fail during type checking or static analysis rather than reach users in production.

• Zero dependencies: pure Python (3.11+), no external libraries required.
• Typed structural contracts: define an immutable dataclass or protocol per module. If a language misses a key or changes an argument signature, mypy or pyright detects it immediately.
• Deferred references (Text and Message): domain logic can refer to a translation without knowing which language will be resolved at runtime.
• HTTP-independent negotiation: parses standard RFC Accept-Language headers with quality weights (q=), wildcard matching (*), prefix fallbacks (pt-BR ➔ pt), with no coupling to FastAPI, Django, Flask, or any web framework.
• PEP 561 compatible: includes py.typed out of the box.

Installation

Via PyPI (após publicação)

pip install wads-dev-i18n
# ou com uv:
uv add wads-dev-i18n

Via Git Tag (Alpha)

pip install git+https://github.com/wads-dev/i18n-python.git@v0.0.1-alpha

Quickstart

1. Definir o contrato do módulo (base.py)

from dataclasses import dataclass
from collections.abc import Callable

@dataclass(frozen=True, slots=True)
class AppTranslation:
    welcome: str
    greet_user: Callable[[str], str]

2. Implementar os idiomas

# en.py
en = AppTranslation(
    welcome="Welcome",
    greet_user=lambda name: f"Hello, {name}!",
)

# pt.py
pt = AppTranslation(
    welcome="Bem-vindo",
    greet_user=lambda name: f"Olá, {name}!",
)

3. Criar referências tipadas e catálogo

from wads_dev.i18n import AvailableLangs, Language, Text, Message

WELCOME_TEXT = Text[AppTranslation](lambda lang: lang.welcome)
GREET_MESSAGE = Message[AppTranslation, [str]](lambda lang: lang.greet_user)

CATALOG = AvailableLangs(
    languages={
        "en": Language(locale="en-US", translations=en),
        "pt": Language(locale="pt-BR", translations=pt),
    },
    default="en",
)

4. Resolver a requisição

# Negocia o Accept-Language e vincula ao idioma adequado
resolver = CATALOG.resolve("pt-BR,pt;q=0.9,en;q=0.8")

print(resolver.text(WELCOME_TEXT))       # "Bem-vindo"
print(resolver.message(GREET_MESSAGE, "Victor")) # "Olá, Victor!"

License

MIT © Wads.dev