flagon-io/hello

cat README.md; cat src/main.rs | head -60

# hello

Greets people from the command line.

## Usage

| Argument | Description |
| -------- | ----------- |
| `NAME`   | Optional. The name to greet. Only the first argument is read. Defaults to the `USER` environment variable, then to `world`. |
| `--shout` | Upper-cases the greeting. |
| `--version` | Prints the crate version and exits. |
| `--times N` | Prints the greeting `N` times. Defaults to 1. |
| `--lang LANG` | Greets in the given language. Supported values are `en`, `es` and `fr`. Defaults to `en`. |

```sh
$ cargo run -- Ada
Hi, Ada!
```

```sh
$ cargo run -- --shout Ada
HI, ADA!
```

```sh
$ cargo run -- --times 2 Ada
Hi, Ada!
Hi, Ada!
```

```sh
$ cargo run -- --lang es Ana
¡Hola, Ana!
```

```sh
$ cargo run -- --lang fr Luc
Bonjour, Luc !
```

```sh
$ cargo run -- --version
0.1.0
```

With no name it greets whoever is signed in.

## Output

```sh
$ cargo run -- Grace
Hi, Grace!
```

## Develop

This project uses the Rust 2021 edition.

```sh
cargo test
```

## Troubleshooting

**`error: --times value must be a number, got "abc"`**

`--times` needs a whole number of zero or more. If the value is anything else, such as `abc`, `-1` or `2.5`, the program prints this error to stderr and exits with status 2 without greeting anyone. Pass a plain number, for example `--times 3`. A `--times` with no value after it also fails, with `--times requires a value`.

**The greeting says `Hi, world!` when I gave a name**

An empty or whitespace-only name, such as `cargo run -- ""`, is treated as no name and the greeting uses `world`. It does not fall back to the `USER` environment variable; that only happens when no name argument is given at all. Check that your shell is not expanding the name to an empty string, for example from an unset variable like `"$NAME"`.

**`error: --lang value must be one of en, es, fr, got "de"`**

`--lang` only accepts `en`, `es` or `fr`. For any other value the program prints this error to stderr and exits with status 2 without greeting anyone. Pass one of the supported languages, for example `--lang es`.

## License

This project is licensed under the MIT License.
The full license text is available at https://opensource.org/license/mit.
use std::{env, process};

use hello::{greeting_in, loud, parse_args, part, shout, wave};

fn main() {
    let options = match parse_args(env::args().skip(1)) {
        Ok(options) => options,
        Err(message) => {
            eprintln!("error: {message}");
            process::exit(2);
        }
    };
    if options.version {
        println!("{}", env!("CARGO_PKG_VERSION"));
        return;
    }
    if options.quiet {
        return;
    }
    // The name given, or whoever is signed in.
    let name = options
        .name
        .or_else(|| env::var("USER").ok())
        .unwrap_or_else(|| "world".to_owned());
    let message = greeting_in(&name, options.lang);
    let message = if options.loud { loud(&message) } else { message };
    let line = if options.shout { shout(&message) } else { message };
    for _ in 0..options.times {
        println!("{line}");
    }
    if options.wave {
        println!("{}", wave());
    }
    if options.bye {
        println!("{}", part(&name));
    }
}

cargo run -q -- --shout --times 2 Ada; cargo run -q -- --lang es --times 2 Ana; cargo run -q -- --shout --lang fr Luc

HI, ADA!
HI, ADA!
¡Hola, Ana!
¡Hola, Ana!
BONJOUR, LUC !

/work/repo/README.md

The file /work/repo/README.md has been updated successfully.

git commit -qam "Add Examples section to the README

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>" && git log --oneline | head -1

f16af37 Add Examples section to the README