vendor/clap/examples/tutorial_derive/01_quick.rs

   1 use std::path::PathBuf;
   2
   3 use clap::{Parser, Subcommand};
   4
   5 #[derive(Parser)]
   6 #[clap(author, version, about, long_about = None)]
   7 struct Cli {
   8     /// Optional name to operate on
   9     #[clap(value_parser)]
  10     name: Option<String>,
  11
  12     /// Sets a custom config file
  13     #[clap(short, long, value_parser, value_name = "FILE")]
  14     config: Option<PathBuf>,
  15
  16     /// Turn debugging information on
  17     #[clap(short, long, action = clap::ArgAction::Count)]
  18     debug: u8,
  19
  20     #[clap(subcommand)]
  21     command: Option<Commands>,
  22 }
  23
  24 #[derive(Subcommand)]
  25 enum Commands {
  26     /// does testing things
  27     Test {
  28         /// lists test values
  29         #[clap(short, long, action)]
  30         list: bool,
  31     },
  32 }
  33
  34 fn main() {
  35     let cli = Cli::parse();
  36
  37     // You can check the value provided by positional arguments, or option arguments
  38     if let Some(name) = cli.name.as_deref() {
  39         println!("Value for name: {}", name);
  40     }
  41
  42     if let Some(config_path) = cli.config.as_deref() {
  43         println!("Value for config: {}", config_path.display());
  44     }
  45
  46     // You can see how many times a particular flag or argument occurred
  47     // Note, only flags can have multiple occurrences
  48     match cli.debug {
  49         0 => println!("Debug mode is off"),
  50         1 => println!("Debug mode is kind of on"),
  51         2 => println!("Debug mode is on"),
  52         _ => println!("Don't be crazy"),
  53     }
  54
  55     // You can check for the existence of subcommands, and if found use their
  56     // matches just as you would the top level cmd
  57     match &cli.command {
  58         Some(Commands::Test { list }) => {
  59             if *list {
  60                 println!("Printing testing lists...");
  61             } else {
  62                 println!("Not printing testing lists...");
  63             }
  64         }
  65         None => {}
  66     }
  67
  68     // Continued program logic goes here...
  69 }