[](https://crates.io/crates/argopt)
[](https://github.com/tanakh/argopt/actions?query=workflow%3A%22Rust%22)
This crate provides attribute macros for command-line argument parsing.
# Usage
Just by adding an attribute `#[cmd]` to a function, the function is converted to a command line program.
```rust,should_panic
#[argopt::cmd]
fn main(host: String, port: u16) {
// ...
}
```
```text
$ cargo run
error: The following required arguments were not provided:
<HOST>
<PORT>
USAGE:
argopt-test <HOST> <PORT>
For more information try --help
```
```text
$ cargo run -- --help
argopt-test
USAGE:
argopt-test <HOST> <PORT>
ARGS:
<HOST>
<PORT>
OPTIONS:
-h, --help Print help information
```
You can customize the behavior of arguments by annotating them with `#[opt(...)]` attributes.
```rust,should_panic
#[argopt::cmd]
fn main(
#[opt(short = 'h', long = "host")]
host: String,
#[opt(short, long, default_value_t = 80)]
port: u16,
) {
// ...
}
```
And you can add help messages by adding doccomments.
```rust,should_panic
/// Sample program
#[argopt::cmd]
fn main(
/// Host name
#[opt(short = 'h', long = "host")]
host: String,
/// Port number
#[opt(short, long, default_value_t = 80)]
port: u16,
) {
// ...
}
```
You can also use the `#[opt(...)]` attribute to customize the behavior of an application.
```rust,should_panic
/// Sample program
#[argopt::cmd]
#[opt(author, version, about, long_about = None)]
fn main(
/// Host name
#[opt(short = 'h', long = "host")]
host: String,
/// Port number
#[opt(short, long, default_value_t = 80)]
port: u16,
) {
// ...
}
```
```text
$ cargo run -- --help
argopt-test 0.1.0
Sample program
USAGE:
argopt-test [OPTIONS] --host <HOST>
OPTIONS:
-h, --host <HOST> Host name
--help Print help information
-p, --port <PORT> Port number [default: 80]
-V, --version Print version information
```
The available options are the same as those of [clap::Parser](https://crates.io/crates/clap).
# Subcommands
You can create sub commands by adding the attribute `#[subcmd]` to functions.
```rust,should_panic
use argopt::{subcmd, cmd_group};
use std::path::PathBuf;
#[subcmd]
fn add(
#[opt(short)]
interactive: bool,
#[opt(short)]
patch: bool,
files: Vec<PathBuf>,
) {
// ...
}
#[subcmd]
fn commit(
#[opt(short)]
message: Option<String>,
#[opt(short)]
all: bool,
) {
// ...
}
#[cmd_group(commands = [add, commit])]
#[opt(author, version, about, long_about = None)]
fn main() {}
```
# Easy Verbosity Level Handling
There is a feature that allows you to interact with the [log](https://crates.io/crates/log) crate and handle the verbosity level automatically.
```rust
use argopt::cmd;
use log::*;
#[cmd(verbose)]
fn main() {
error!("This is error");
warn!("This is warn");
info!("This is info");
debug!("This is debug");
trace!("This is trace");
}
```
```text
$ cargo run
This is error
$ cargo run -- -v
This is error
This is warn
$ cargo run -- -vv
This is error
This is warn
This is info
$ cargo run -- -vvv
This is error
This is warn
This is info
This is debug
$ cargo run -- -vvvv
This is error
This is warn
This is info
This is debug
This is trace
```
You can also use `verbose` option to subcommand application.
```rust,ignore
...
#[cmd_group(commands = [add, commit], verbose)]
fn main() {}
```