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Diffstat (limited to 'clap/examples/06_positional_args.rs')
| -rw-r--r-- | clap/examples/06_positional_args.rs | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/clap/examples/06_positional_args.rs b/clap/examples/06_positional_args.rs new file mode 100644 index 0000000..1f29612 --- /dev/null +++ b/clap/examples/06_positional_args.rs @@ -0,0 +1,56 @@ +extern crate clap; + +use clap::{App, Arg}; + +fn main() { + + // Positional arguments are those values after the program name which are not preceded by any + // identifier (such as "myapp some_file"). Positionals support many of the same options as + // flags, as well as a few additional ones. + let matches = App::new("MyApp") + // Regular App configuration goes here... + + // We'll add two positional arguments, a input file, and a config file. + // + // I'll explain each possible setting that "positionals" accept. Keep in + // mind that you DO NOT need to set each of these for every flag, only the + // ones that apply to your individual case. + .arg(Arg::with_name("input") + .help("the input file to use") // Displayed when showing help info + .index(1) // Set the order in which the user must + // specify this argument (Starts at 1) + .requires("config") // Says, "If the user uses "input", they MUST + // also use this other 'config' arg too" + // Can also specify a list using + // requires_all(Vec<&str>) + .conflicts_with("output") // Opposite of requires(), says "if the + // user uses -a, they CANNOT use 'output'" + // also has a conflicts_with_all(Vec<&str>) + .required(true) // By default this argument MUST be present + // NOTE: mutual exclusions take precedence over + // required arguments + ) + .arg(Arg::with_name("config") + .help("the config file to use") + .index(2)) // Note, we do not need to specify required(true) + // if we don't want to, because "input" already + // requires "config" + // Note, we also do not need to specify requires("input") + // because requires lists are automatically two-way + + // NOTE: In order to compile this example, comment out conflicts_with() + // because we have not defined an "output" argument. + .get_matches(); + + // We can find out whether or not "input" or "config" were used + if matches.is_present("input") { + println!("An input file was specified"); + } + + // We can also get the values for those arguments + if let Some(in_file) = matches.value_of("input") { + // It's safe to call unwrap() because of the required options we set above + println!("Doing work with {} and {}", in_file, matches.value_of("config").unwrap()); + } + // Continued program logic goes here... +} |