cling

cling is a Rust framework that simplifies building command-line programs using clap.rs.

Note: This project is in alpha stage and should not be used in production use cases. APIs can break without prior notice. Please provide feedback through github issues.

Dual-licensed under Apache 2.0 or MIT.

About

cling name is a play on CLI-ng (as in next-gen) and "cling" the english word, as it enables function handlers to cling to clap user-defined structs 😉.

The handler design is inspired by Axum, therefore, I like to think about cling as "Axum for command-line applications".

For more details, see: - docs.rs - examples

Example

```rust use cling::prelude::*;

[derive(CliRunnable, Parser, Debug, Clone)]

[cling(run = "run")]

pub struct App { #[command(flatten)] pub options: Options, }

// Structs that derive CliParam are optionally available for handlers as // parameters both as value and reference.

[derive(CliParam, Parser, Debug, Clone)]

pub struct Options { /// Turn debugging information on #[arg(short, long, action = clap::ArgAction::Count)] pub debug: u8, }

// handlers can be sync or async, cling will handle this transparently. pub async fn run(options: &Options) { println!("Opts: {options:?}"); }

[tokio::main]

async fn main() { let app = App::parse(); app.runandexit().await; } ```

Run it with: ```console $ simple -d -d Opts: Options { debug: 2 }

```

Design direction

• Support both async and sync Rust command-line applications and don't tie to specific async runtime.
• Promote specific design patterns with limited escape hatches.
• Creates CLIs that follow design best practices by default:
  • Support for configuration
  • Logging
  • Unit testable commands
  • Propagates errors to main with sane default printer
  • Translates Result::Err to non-zero exit codes
  • Support for building REPLs
  • Do we want to support non-derive clap as well? No!

Minimum Supported Rust Version (MSRV)

Cling's MSRV is 1.65.0.