Extends internationalization support from 2 languages (EN, DE) to 17 total
languages, meeting the DatesAPI website's advertised language count.
Added languages (15):
- Latin script: ES, FR, IT, PT, NL, PL, RU, TR, VI
- Non-Latin script: JA, KO, ZhCN, ZhTW, HI, TH
Changes:
- Added 15 new Lang constants to date.go (using ZhCN/ZhTW naming convention)
- Extended all 5 i18n maps in i18n.go with CLDR-accurate translations:
* monthNames: 12 months × 15 languages (180 entries)
* monthNamesShort: 12 abbreviated months × 15 languages
* weekdayNames: 7 weekdays × 15 languages (105 entries)
* weekdayNamesShort: 7 abbreviated weekdays × 15 languages
* durationUnits: 7 units × 2 forms × 15 languages (210 entries)
- Documented plural form limitation for PL/RU (complex plural rules)
- Added comprehensive test coverage (135 new test cases)
- Verified UTF-8 encoding for non-Latin scripts
Test results:
- All 955 tests passing
- Coverage: 99.5% (exceeds 95% target)
- No performance regression (static data only)
Closes: quando-cvw
Add internationalization support with translation data for English and
German languages. This provides the foundation for localized formatting
of dates and durations.
Changes:
- Add i18n.go with translation maps for month names, weekday names,
and duration units (both EN and DE)
- Implement helper methods on Lang type: MonthName, MonthNameShort,
WeekdayName, WeekdayNameShort, DurationUnit
- Add automatic fallback to English for unknown languages
- Create comprehensive test suite in i18n_test.go (97.8% coverage)
- Update Lang type documentation with future expansion notes
- Add example tests demonstrating i18n usage
Blocks: quando-10t, quando-5ol, quando-95w
Add In() method to Date type for converting between IANA timezones.
Implements comprehensive DST handling with proper wall-clock time
preservation across daylight saving transitions.
Features:
- In(location) converts to specified IANA timezone
- Returns ErrInvalidTimezone for invalid timezone names
- Never panics on invalid input
- Preserves language settings across conversions
- Maintains immutability pattern
DST Handling:
- Add(1, Days) preserves wall clock time, not duration
- Tested across spring forward (Mar 29, 2026)
- Tested across fall back (Oct 25, 2026)
Testing:
- 100% coverage for In() method
- 6 comprehensive test functions (228 lines)
- Tests for Europe/Berlin, America/New_York, Asia/Tokyo, UTC
- Error handling tests (empty string, invalid timezones)
- Immutability and language preservation tests
- 3 example tests demonstrating usage
Overall coverage: 98.1%
- Add Date struct with time.Time and Lang fields
- Implement package-level constructors: Now(), From(time.Time)
- Add conversion methods: Time(), Unix(), FromUnix(int64)
- Support negative Unix timestamps (dates before 1970)
- Support full time.Time range (year 0001-9999+)
- Add WithLang() for i18n support (placeholder)
- Create package documentation in quando.go
- Comprehensive unit tests with 100% coverage
- Example tests for godoc
- Verify immutability through tests
All acceptance criteria met:
✓ Date struct defined with time.Time and Lang fields
✓ Now() returns current date
✓ From(time.Time) converts to Date
✓ Time() extracts underlying time.Time
✓ Unix() returns Unix timestamp (int64)
✓ FromUnix(int64) creates Date from timestamp
✓ Unit tests with 100% coverage (exceeds 95% requirement)
✓ Godoc comments for all exported types/functions
✓ Example tests in example_test.go
