flagon-io/hello

cat README.md src/main.rs && git log --stat -3 | head -30

{"number":72,"repo":"repo"}

# 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.

## Examples

```sh
$ cargo run -- --shout --times 2 Ada
HI, ADA!
HI, ADA!
```

```sh
$ cargo run -- --lang es --times 2 Ana
¡Hola, Ana!
¡Hola, Ana!
```

```sh
$ cargo run -- --shout --lang fr Luc
BONJOUR, LUC !
```

## 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));
    }
}
commit f16af37c620d8571880ae073e8966e2d691d335f
Author: g1t agent <agent@g1t.sh>
Date:   Sat Oct 3 03:10:31 2026 +0000

    Add Examples section to the README
    
    Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

 README.md | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

commit ac45e1027ebe600d5e501e0e7a8aa975e2ef1c3b
Merge: 69796cb ebbaeb2
Author: g1t agent <agent@g1t.sh>
Date:   Sat Oct 3 02:21:57 2026 +0000

    Merge main into wave flag branch
    
    Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

commit 69796cb2d7cd277e3d2fe4422db4c695bb06cdc5
Author: g1t agent <agent@g1t.sh>
Date:   Sat Oct 3 02:13:11 2026 +0000

    Add --wave flag that prints o/ after the greeting
    
    Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

 src/lib.rs  | 21 +++++++++++++++++++++
 src/main.rs |  5 ++++-

A g1t agent's token works in syntaqx/hello only.

grep -n '"-' -B2 -A8 src/lib.rs | head -120

76-    let mut args = args.into_iter();
77-    while let Some(arg) = args.next() {
78:        if arg == "--shout" {
79-            options.shout = true;
80:        } else if arg == "--version" {
81-            options.version = true;
82:        } else if arg == "--quiet" {
83-            options.quiet = true;
84:        } else if arg == "--loud" || arg == "-L" {
85-            options.loud = true;
86:        } else if arg == "--bye" {
87-            options.bye = true;
88:        } else if arg == "--wave" {
89-            options.wave = true;
90:        } else if arg == "--times" {
91-            let value = args
92-                .next()
93:                .ok_or_else(|| "--times requires a value".to_owned())?;
94-            options.times = value
95-                .parse()
96:                .map_err(|_| format!("--times value must be a number, got {value:?}"))?;
97:        } else if arg == "--lang" {
98-            let value = args
99-                .next()
100:                .ok_or_else(|| "--lang requires a value".to_owned())?;
101-            options.lang = Lang::parse(&value).ok_or_else(|| {
102:                format!("--lang value must be one of en, es, fr, got {value:?}")
103-            })?;
104:        } else if !arg.starts_with("--") && options.name.is_none() {
105-            options.name = Some(arg);
106-        }
107-    }
108-    Ok(options)
109-}
110-
111-/// `text` upper-cased.
112-pub fn shout(text: &str) -> String {
--
157-    #[test]
158-    fn parse_args_quiet() {
159:        assert!(parse_args(args(&["--quiet", "Ada"])).unwrap().quiet);
160-        assert!(!parse_args(args(&["Ada"])).unwrap().quiet);
161-    }
162-
163-    #[test]
164-    fn parse_args_bye() {
165:        assert!(parse_args(args(&["--bye", "Ada"])).unwrap().bye);
166-        assert!(!parse_args(args(&["Ada"])).unwrap().bye);
167-    }
168-
169-    #[test]
170-    fn parse_args_wave() {
171:        assert!(parse_args(args(&["--wave", "Ada"])).unwrap().wave);
172-        assert!(!parse_args(args(&["Ada"])).unwrap().wave);
173-    }
174-
175-    #[test]
176-    fn wave_is_o_slash() {
177-        assert_eq!(wave(), "o/");
178-    }
179-
180-    #[test]
181-    fn parse_args_loud() {
182:        assert!(parse_args(args(&["--loud", "Ada"])).unwrap().loud);
183:        assert!(parse_args(args(&["-L", "Ada"])).unwrap().loud);
184-        assert!(!parse_args(args(&["Ada"])).unwrap().loud);
185-    }
186-
187-    #[test]
188-    fn loud_uses_three_exclamation_marks() {
189-        assert_eq!(loud(&hail("Ada")), "Hi, Ada!!!");
190-    }
191-
--
203-    fn parse_args_skips_leading_flag() {
204-        assert_eq!(
205:            parse_args(args(&["--unknown", "Ada"])).unwrap().name.as_deref(),
206-            Some("Ada")
207-        );
208-    }
209-
210-    #[test]
211-    fn parse_args_shout_defaults_off() {
212-        assert!(!parse_args(args(&["Ada"])).unwrap().shout);
213-    }
--
215-    #[test]
216-    fn parse_args_shout_before_name() {
217:        let options = parse_args(args(&["--shout", "Ada"])).unwrap();
218-        assert!(options.shout);
219-        assert_eq!(options.name.as_deref(), Some("Ada"));
220-    }
221-
222-    #[test]
223-    fn parse_args_shout_after_name() {
224:        let options = parse_args(args(&["Ada", "--shout"])).unwrap();
225-        assert!(options.shout);
226-        assert_eq!(options.name.as_deref(), Some("Ada"));
227-    }
228-
229-    #[test]
230-    fn parse_args_shout_alone() {
231:        let options = parse_args(args(&["--shout"])).unwrap();
232-        assert!(options.shout);
233-        assert_eq!(options.name, None);
234-    }
235-
236-    #[test]
237-    fn parse_args_version_defaults_off() {
238-        assert!(!parse_args(args(&["Ada"])).unwrap().version);
239-    }
--
241-    #[test]
242-    fn parse_args_version() {
243:        let options = parse_args(args(&["--version"])).unwrap();
244-        assert!(options.version);
245-        assert_eq!(options.name, None);
246-    }
247-
248-    #[test]

grep -n 'pub fn part' -A4 src/lib.rs

143:pub fn part(name: &str) -> String {
144-    let trimmed = name.trim();
145-    let display_name = if trimmed.is_empty() { "world" } else { trimmed };
146-    format!("Goodbye, {display_name}!")
147-}

python3 - <<'E'
p='README.md'
s=open(p).read()
a="Defaults to `en`. |\n"
assert a in s
s=s.replace(a,a+"""| `--loud`, `-L` | Ends the greeting with `!!!` instead of `!`. |
| `--bye` | Prints `Goodbye, NAME!` after the greeting. |
| `--wave` | Prints `o/` after the greeting. |
| `--quiet` | Prints no greeting at all. `--version` still prints the version. |
""",1)
s=s.replace("With no name it greets whoever is signed in.","With no arguments it greets whoever is signed in (the `USER` environment variable), or `world` if that is not set, and prints `Hi, NAME!`. Flags may come before or after the name, and unrecognised `--` options are ignored.",1)
open(p,'w').write(s)
E
git diff --stat; git commit -qam "Document every command-line option in the README

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>"

README.md | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)