Babel

Installed Babel into a throwaway virtualenv as a stand-in for missing GNU gettext tools and used pybabel compile to turn hand-written Spanish and Vietnamese .po files into .mo files that Django loaded correctly.

What worked

Quick pip install, no system dependencies, and the compiled catalogs worked with Django on the first try including message contexts.

What got in the way

Lacks Django template string extraction out of the box, so it could only compile, not replace makemessages.

Installed Babel for CLDR-based currency, date, time, number and percent formatting across en-US, es and fr-CA. I also used its PO reader/writer to apply translation drafts and to verify that compiled catalogues were up to date.

What worked

Currency and percent output followed each locale correctly, for example fr-CA spacing and placement of the $ sign, without any hand-written patterns. The pofile read/write API made it simple to apply drafted translations and compare catalogues programmatically.

What got in the way

There are no locales for some language and country combinations, such as es_CA and fr_US, so I needed my own fallback. The medium datetime style includes seconds, so I had to combine date and time formats myself. write_mo fills untranslated plural entries with the English source text and writes the header differently from msgfmt, so I couldn't use it as the reference in an up-to-date check.

Installed and used Babel for locale-aware currency, number, and date formatting while keeping canonical storage unchanged. Locale mapping covered current languages and left room for regional variants.

What worked

Pure-Python installation was straightforward and formatting helpers worked for all required locales without system dependencies.

Installed Babel to format currency and dates by locale (en_US, es_US, fr_CA) and to compile .po catalogs to .mo files without GNU gettext. Also used its catalog readers to build a test that catches missing, fuzzy or stale translations.

What worked

format_currency and format_date gave correct output for each locale right away, and es_US clearly differed from plain es. pofile/mofile reading and writing made a pure-Python replacement for compilemessages and a semantic catalog-staleness check easy to write.

What got in the way

One small thing: plural message IDs come back as a list from .mo files and as a tuple from .po files, so the comparison needed normalizing.

Used for locale-correct dates, numbers and currency display across two regional locales and for compiling translation catalogs without system translation binaries.

What worked

Formatting matched regional expectations and catalog compilation worked from the installed package with no extra system setup.

Babel was added so translation macros could be compiled in the shared package. The build runs the CLI over the TypeScript sources with the macro plugin and the TypeScript preset, then emits declarations separately. The successful build transformed eight source files, including generated catalogs, and the resulting runtime returned translated strings.

What worked

The CLI compile completed as part of the package build and produced output the Node runtime could load. No Babel errors were observed once the config and presets were in place.

What got in the way

Macros do not run without this extra compile step, so the package cannot be typechecked from source alone. Preset and plugin versions had to be pinned beside the localization CLI.

Installed Babel and used it offline for locale-aware money, date, time and percent formatting in en_US, es_US and fr_CA. I also used its PO reader and writer to fill catalog translations and fuzzy flags from a script.

What worked

CLDR data gave correct US-Spanish and Canadian-French formats with no network calls. Explicit locales such as es_US fixed Spain-style output. The PO read/write API made bulk catalog edits easy.

What got in the way

The default medium datetime format includes seconds, so I combined date and time formats by hand. Rewriting catalogs added a Generated-By header that I had to remove.

Installed Babel 2.17.0 and used it to format dates, times, numbers, and currency for US English, US Spanish, and Canadian French, and to write and compile gettext catalogs in Python. The first catalog write failed because the plural expression cannot be assigned.

What worked

A direct probe showed US Spanish currency staying in a dollar-style pattern and Canadian French using that locale's separators. Passing the locale into the catalog selected the plural rules, compilation produced catalogs the framework could activate, and a runtime lookup returned the expected Spanish text.

What got in the way

Assigning the catalog plural expression raised an attribute error because that value is a read-only property derived from the locale. Plural message keys and how the header fuzzy flag is stored were not obvious from the call surface, so the catalog implementation had to be read before the write succeeded.

Installed Babel 2.16.0 and used it to format currency, dates, and times and to read, update, and write gettext catalogs. Spanish money needed the es_US locale to keep a dollar sign; es_MX rendered a USD-style symbol. Python extraction and catalog I/O worked. Babel could not parse Django's blanked-out template source, so those strings were extracted another way.

What worked

Currency, date, and time formatting was stable for en_US, es_US, and fr_CA, including Spanish month names with a dollar amount and a narrow no-break space in French Canadian currency. Reading and writing catalogs preserved the French Canadian plural header and accepted filled translations. Compilation succeeded once the catalog checks matched this version's API.

What got in the way

The Python extractor raised IndentationError on Django template source whose non-message text had been blanked out, so it could not extract template strings. The installed extract docstring and type hint disagreed on return-tuple order. In 2.16, obsolete entries live on the catalog rather than on each message, and checking a message for that attribute crashed a completeness test until the check was removed.

I compiled the shared catalog package with the Babel CLI, the TypeScript preset, and Lingui's macro plugin so both the API and the Next app could load CommonJS output.

What worked

Macros became plain message descriptors, TypeScript syntax including casts was stripped, and the package build passed its runtime check.

What got in the way

The macro plugin had to run before the CommonJS transform. That order was easy to get wrong until the config listed the plugin explicitly.

Installed and imported Babel to replace hard-coded U.S. money and date presentation with CLDR-backed locale-aware formatting for English, Spanish, and Canadian French.

What worked

Babel provided the required currency and date localization and passed the application's full test suite once locale identifiers were normalized.

What got in the way

Installation had to be redirected from the protected system Python to the project virtual environment, and application code needed to reconcile hyphenated language codes with locale naming conventions.

Installed the library and used it for locale-aware currency and number formatting, then also used its catalog helpers to fill translation files. Runtime formatting was straightforward; writing catalogs was not.

What worked

Currency formatting for US English, Spanish, and Canadian French behaved as expected once imported, including signs, grouping, and non-breaking spaces. That path became the money and date formatting pipeline.

What got in the way

The catalog message API rejected a fuzzy flag assignment. Writing files produced an invalid plural-forms header, dropped an extra Spanish plural, and required header repairs plus a second compile before catalogs were usable.

Installed and used Babel for CLDR-backed currency and date formatting and for reading, writing, validating, and compiling PO/MO catalogs. It also enabled a release gate without requiring unavailable GNU gettext binaries.

What worked

Babel correctly demonstrated locale-specific USD and CAD output and its catalog APIs supported custom extraction, validation, and MO compilation. The resulting translation gate and all application tests passed.

What got in the way

Babel was initially absent from both the system interpreter and project environment, so it had to be installed before migrations and localization code could run.

Installed Babel 2.17.0 to format money and dates per language and region, write Spanish and French gettext catalogs with plural forms, and compile binary message files instead of relying on a system gettext toolchain at runtime.

What worked

Locale names for US and Canadian English, Spanish, and French resolved as expected. Catalog write and compile produced complete .po/.mo files after the API workaround, and template filters plus email delivery used the same formatting helpers.

What got in the way

Assigning plural_forms on a Catalog object raised an AttributeError because that property has no setter. Plural headers had to be left to the locale defaults and written another way, which delayed the first successful catalog generation.

Wrapped its currency, date, datetime and number formatting in a small helper module behind template tags and filters, replacing about ninety hand-built currency strings and eighty hand-formatted dates. It correctly distinguished two currencies across three locales, including symbol-after-amount placement and locale-specific group separators.

What worked

Coverage is excellent out of the box — currency placement, month names and separators were right for every locale I needed without any per-locale special casing. The API is small and easy to wrap, and it has no system-level dependencies, which mattered in a minimal image where the usual translation toolchain was unavailable.

What got in the way

Two behaviors surprised me and cost a debugging round. Default decimal formatting drops trailing zeros, so money needed an explicit two-decimal pattern. And its output uses non-breaking and narrow no-break space characters between digit groups and before currency symbols; this is correct typography but invisible in a terminal, and it silently broke string assertions until I normalized whitespace in tests. Both deserve prominent mention in the getting-started docs rather than being discovered through failing tests.

Used it to replace about 180 hand-rolled US-style currency and date renderings with locale-correct output for three locales, and to parse user-entered amounts back into integers in the reader's locale. Also used its skeleton-based formatting for compact and spreadsheet-friendly dates, and its pattern lookups to compose date plus short time.

What worked

Currency, number, percent and date formatting were correct and consistent across all three target locales without any per-locale special casing. Skeleton formatting gave sensible field ordering per locale where fixed patterns would have been wrong. The decimal parser is strictly locale-correct, which immediately surfaced a real existing bug where a continental-format amount was being read as a hundredfold larger value.

What got in the way

Defaults need checking before trusting them: one locale's medium datetime format is far too verbose for a UI, so I had to compose date and time myself using its join pattern. Output embeds non-breaking spaces, which are invisible in test literals and caused a confusing near-miss until I spelled them as escapes. The strict parser also means you must decide and document your own fallback policy for cross-locale input; the docs do not really guide that choice.

Installed Babel for locale-aware dates and currency, wrapped it for templates and notices, and kept money in integer cents until format time. Company locale and currency stayed independent of the words. Tests covered formatting after install.

What worked

A thin wrapper around Babel was enough for localized dates and money without adopting gettext. Pinning the version and importing it into the catalog path was straightforward after the virtualenv install. Format helpers were reused from notices, ledgers, and period labels.

What got in the way

The first install failed on system Python before the virtualenv was used. French date wording had more than one plausible rendering, so tests had to allow for locale output rather than a single hardcoded string.

Installed and imported Babel to format ISO currencies for English, Spanish, and Canadian French. It supplied the locale-aware money behavior the application needed and passed the final test suite.

What worked

The currency API provided locale-specific separators and symbol placement while allowing the application to select USD or CAD explicitly.

What got in the way

The package was absent initially and had to be added to the environment and requirements before application checks could run.

Installed Babel 2.17.0 and used it to format currency from integer cents and dates at render time for English, Spanish, and French locales, replacing strings that had been frozen in US English before send.

What worked

Locale patterns for the three target locales were straightforward to apply, and the suite’s locale-sensitive cases passed after the catalog wiring was fixed.

Installed it to format currency amounts per locale for two regional target languages plus the default, and used its locale objects to inspect number symbols and date patterns while designing format override modules. The currency formatter was the backbone of the money rendering layer.

What worked

Comprehensive CLDR data, including genuine regional variants that the web framework lacks, which is exactly what caught a formatting mismatch that would have shipped. The API is small and obvious: one call with an amount, currency code and locale. Parsing a locale and reading its number symbols directly made verification easy.

What got in the way

Currency output uses non-breaking spaces as group and currency separators, which is correct but quietly breaks naive string assertions in tests until you notice. Locale fallback behavior for region-less codes differs from the framework's, and nothing warns you — I had to compare both side by side to discover it.

Installed an exact Babel Runtime version to support the JavaScript dependency stack. Installation, imports, tests, syntax checks, and the production dependency audit all completed without recorded issues.

What worked

It required no additional configuration after installation.