gettext-tstrings¶

Safe gettext and Babel integration for Python 3.14+ t-strings.

import gettext

from gettext_tstrings import Translator

_ = Translator(gettext.translation("messages", localedir="locales"))
name = "Ada"
print(_(t"Hello {name}"))

The catalog receives the complete sentence Hello {name}. A translation may reorder or repeat {name}; it may not drop it, invent one, or attach formatting of its own.

Why t-strings¶

An f-string is already interpolated by the time any library sees it, so translating one means translating a fragment. A t-string (PEP 750) keeps the static text, the evaluated values, the source expressions, the conversions, and the format specs separate — which is exactly the split a message catalog needs.

Nothing in gettext or Babel says how a t-string becomes a message, though. This library makes that choice, writes it down as a versioned specification, and ships the conformance suite to check it.

The choice it makes¶

• Translate complete messages, never sentence fragments.
• Accept only simple variable names such as {name}.
• Keep !r and :.2f under application control, out of the catalog.
• Let translators reorder and repeat known placeholders — but not call attributes, and not add formatting behaviour.
• Reuse ordinary POT, PO, and MO files, and the tools that already read them.

Install¶

python -m pip install gettext-tstrings

Python 3.14 or newer. Rendering has no dependencies — it uses the standard library's gettext and nothing else.

Extraction and catalog validation run through Babel, so install that extra wherever pybabel runs, which is usually a development or CI environment rather than a production image:

python -m pip install "gettext-tstrings[babel]"

Where to go next¶