README.md

cli-rs

🚧 wip 🚧

A library to help you quickly write expressive CLIs. Built from the ground up with advanced features like dynamic completions in mind.

Command::name("lockbook")
   .subcommand(
       Command::name("edit")
           .input(Arg::new("target"))
           .handler(|target: Arg<String>| println!("editing target file: {}", target.get())),
   )
   .parse();

Specify complicated arguments that are used often:

let docs = Arg::<Uuid>::new("target-file")
    .description("A uuid or path of a lockbook document")
    .parser(|str| {...})
    .completions(|current_str, cursor_loc| {...});

cli-rs will automatically generate contextual help messages, and man pages. cli-rs will also generate a tiny completions file for every shell which will call your CLI, moving as much of the completion logic into Rust as possible.

spec

command_path --flags positional_args --flags positional_args

things for now

• args are all required and must be provided in order
• flags are always optional (must impl default) and can be provided out of order
• flags that aren't booleans follow the form --key=value
• boolean that are boolean are parsed as either --key, --key=false, or -k
• a command can have subcommands or args & flags, but not both

things for later:

• support --key value
• can define an environment variable for flag values (cli specified value, env var fallback, then Default::default())
• subcommands inherit any flags as their own flags
• additionally all boolean flags can be grouped, such as -rf
• list args (support for optional args)
• detect invalid configuration at runtime