Crate clickrs[][src]

Expand description

Simplified CLI creation via procedural macros.

For the time being you must also have structopt as a dependency to use clickrs.

This crate is largely inspired by the click Python package which allows for defining command line interfaces very simply through the use of decorators ( In clickrs, we export a precedural macro to mimic this functionality of click: command.

Thanks to the fantastic work done by the structopt package and taking inspiration from the Python fire package (, we have taken this a step further. Building clickrs on structopt allows us to leverage the argument types in the function wrapped by the command procedural macro, which allows for very clean and succinct CLI definitions.

To be clear, argument is not a macro, it’s just used as a way to provide a macro-like interface for command to pick up additional options for each argument, so you won’t need to import it.

Re-implementing the example CLI in the structopt documention (, with clickrs we can simplify it even further:

use clickrs::command;
use std::path::PathBuf;

#[command(name = "basic")]
#[argument("debug", short, long)]
#[argument("verbose", short, long, parse(from_occurrences))]
#[argument("speed", short, long, default_value = "42")]
#[argument("output", short, long, parse(from_os_str))]
#[argument("nb_cars", short = "c", long)]
#[argument("level", short, long)]
#[argument("files", name = "FILE", parse(from_os_str))]
fn main(
    debug: bool,
    verbose: u8,
    speed: f64,
    output: PathBuf,
    nb_cars: Option<i32>,
    level: Vec<String>,
    files: Vec<PathBuf>,
) {
    println!("{:?}", speed);

Defaults without using argument

You only need to use argument if you need to specify additional options for the CLI inputs. As shown below, if the defaults provided by structopt are what you need, we can use the defaults provided by structopt by foregoing the calls to argument. This makes defining a CLI even easier:

use clickrs::command;

    name = "example",
    about = "An example of clickrs with defaults for arguments."
fn main(
    input: String,
    file_name: Option<String>,
) {
    println!("{}, {:?}", input, file_name);

which looks like:

example 0.1.0
An example of clickrs with defaults for arguments.

    clickrs <input> [file-name]

    -h, --help       Prints help information
    -V, --version    Prints version information



pub use structopt;

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