CommandContext

Every command handler receives a &CommandContext as its only argument. It contains everything vecli parsed from the command line for that invocation.

#![allow(unused)]
fn main() {
fn my_command(ctx: &CommandContext) {
    // ctx is yours to use
}
}

Fields

ctx.subcommand

The name of the command as typed by the user, e.g. "add" or "list".

#![allow(unused)]
fn main() {
println!("Running: {}", ctx.subcommand);
}

ctx.positionals

A Vec<String> of all non-flag tokens that followed the subcommand, in order.

mytool add "buy milk" groceries
# ctx.positionals == ["buy milk", "groceries"]

#![allow(unused)]
fn main() {
let task = ctx.positionals.first().map(String::as_str).unwrap_or("unnamed");
}

ctx.flags

A HashMap<String, String> of all flags passed by the user, keyed by canonical name after alias resolution. Boolean flags (no explicit value) have the value "true".

mytool add "buy milk" --priority high -v
# ctx.flags == { "priority": "high", "verbose": "true" }

#![allow(unused)]
fn main() {
if ctx.flags.contains_key("verbose") {
    println!("verbose mode");
}

let priority = ctx.flags.get("priority").map(String::as_str).unwrap_or("medium");
}

Global flags registered on the app are merged in automatically — no extra setup needed in the handler.

Full Example

#![allow(unused)]
fn main() {
fn add(ctx: &CommandContext) {
    let task = ctx.positionals.first().map(String::as_str).unwrap_or("unnamed");
    let priority = ctx.flags.get("priority").map(String::as_str).unwrap_or("medium");

    if ctx.flags.contains_key("verbose") {
        println!(
            "[verbose] subcommand='{}', positionals={:?}, flags={:?}",
            ctx.subcommand, ctx.positionals, ctx.flags
        );
    }

    println!("Added '{}' with priority {}.", task, priority);
}
}

Now our app is looking a bit dry, it only accepts commands with no further elaboration. Interact with the user using the Terminal, a collection of interactive terminal prompt utilities.