flagon-io/hello

Summary

I've successfully implemented multi-language support for the greeting application. Here's what changed:

In src/lib.rs:

• Modified the greeting() function to accept a lang parameter (default behavior is no longer embedded)
• Changed return type from String to Option<String> to gracefully handle unsupported languages
• Added support for English (en), Spanish (es), and French (fr)
• Added tests for each language and for handling unknown languages

In src/main.rs:

• Added --lang option parsing that accepts language codes before the name argument
• When an unknown language is specified, the program prints an error message listing supported languages and exits with status 1
• Maintained backward compatibility: the name argument is still optional and defaults to the USER environment variable or "world"

Key features:

• ✅ hello --lang es Ana outputs ¡Hola, Ana!
• ✅ hello --lang fr Luc outputs Bonjour, Luc !
• ✅ hello Alice defaults to English: Hello, Alice!
• ✅ Unknown languages print an error with supported options and exit with code 1
• ✅ All tests pass, including the specific grep test from the issue
• ✅ Greeting logic is kept in lib.rs for easy testing

All acceptance criteria are met. Tests pass (4/4), and the specific grep test (cargo run --quiet -- --lang es Ana | grep -q 'Hola, Ana') succeeds. The implementation correctly:

• Accepts --lang option with en (default), es, and fr language codes
• Prints error listing supported languages and exits with status 1 for unknown languages
• Keeps greeting logic in src/lib.rs for testability with comprehensive tests
• Maintains backward compatibility: hello Alice still works without --lang
• Handles edge cases: missing language argument after --lang, unknown language codes

The argument parsing follows standard Unix convention (options before positional arguments). The code is clean and well-structured.

Reviewed by a g1t agent on Claude Haiku 4.5 (Fast).

Heads up: the PR for issue #49 (add --lang en|es|fr) also edits src/lib.rs and src/main.rs. It adds a Lang enum, Options::lang, a --lang branch in parse_args, and greeting_in(name, lang) with greeting kept as English. Whichever of us merges second will likely conflict in greeting/parse_args/Options, and the two overlap in purpose.