Add ParseWithLayout() function to handle ambiguous and custom date formats
by providing an explicit Go layout string.
Implementation:
- ParseWithLayout(s, layout string) delegates to time.Parse()
- Wraps result in quando.Date with default EN language
- Returns ErrInvalidFormat on parse failure
- Trims whitespace and validates empty input
- Never panics, always returns errors as values
Features:
- Disambiguate US vs EU slash formats (01/02/2026)
- Support custom formats with month names (9. February 2026)
- Full Go layout format support (reference date: Mon Jan 2 15:04:05 MST 2006)
- Thread-safe and immutable
Testing:
- 13 success test cases (US/EU, custom formats, edge cases)
- 8 error test cases (invalid inputs, validation)
- Immutability test
- 2 benchmarks: ~87-104 ns/op (100x faster than 10µs target)
- Zero allocations
- 100% test coverage for new code
- 3 example tests demonstrating key use cases
Files modified:
- parse.go: Added ParseWithLayout() with comprehensive godoc
- parse_test.go: Added 21 test cases + 2 benchmarks
- example_test.go: Added 3 example functions
Implement Parse() function that automatically detects and parses common
date formats without requiring explicit layout strings. This provides an
intuitive API for parsing dates from various sources while maintaining
type safety through proper error handling.
Supported formats:
- ISO format (YYYY-MM-DD): "2026-02-09"
- ISO with slash (YYYY/MM/DD): "2026/02/09"
- EU format (DD.MM.YYYY): "09.02.2026"
- RFC2822/RFC1123: "Mon, 09 Feb 2026 00:00:00 +0000"
Key features:
- Detects and rejects ambiguous slash formats (e.g., "01/02/2026")
- Returns clear, contextual errors for invalid or ambiguous inputs
- Never panics - all errors via return values
- Zero allocations for successful parses
- Comprehensive test coverage (98%)
Performance results:
- ISO format: 105.5 ns/op (94x faster than 10µs target)
- ISO slash: 118.3 ns/op
- EU format: 117.4 ns/op
- RFC2822: 257.8 ns/op
Test coverage:
- 42 unit tests covering valid formats, error cases, edge cases
- 3 example tests demonstrating usage patterns
- Benchmarks for all format types
- Parse() function: 100% coverage
Files added:
- parse.go: Main implementation with Parse() and helper functions
- parse_test.go: Comprehensive test suite with table-driven tests
Files modified:
- example_test.go: Added ExampleParse examples
