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Diffstat (limited to 'clap/examples/03_args.rs')
| -rw-r--r-- | clap/examples/03_args.rs | 84 |
1 files changed, 0 insertions, 84 deletions
diff --git a/clap/examples/03_args.rs b/clap/examples/03_args.rs deleted file mode 100644 index c62d576..0000000 --- a/clap/examples/03_args.rs +++ /dev/null @@ -1,84 +0,0 @@ -extern crate clap; - -use clap::{App, Arg}; - -fn main() { - // Args describe a possible valid argument which may be supplied by the user at runtime. There - // are three different types of arguments (flags, options, and positional) as well as a fourth - // special type of argument, called SubCommands (which will be discussed separately). - // - // Args are described in the same manner as Apps using the "builder pattern" with multiple - // methods describing various settings for the individual arguments. Or by supplying a "usage" - // string. Both methods have their pros and cons. - // - // Arguments can be added to applications in two manners, one at a time with the arg(), and - // arg_from_usage() method, or multiple arguments at once via a Vec<Arg> inside the args() method, - // or a single &str describing multiple Args (one per line) supplied to args_from_usage(). - // - // There are various options which can be set for a given argument, some apply to any of the - // three types of arguments, some only apply one or two of the types. *NOTE* if you set - // incompatible options on a single argument, clap will panic! at runtime. This is by design, - // so that you know right away an error was made by the developer, not the end user. - // - // # Help and Version - // clap automatically generates a help and version flag for you, unless you specify your - // own. By default help uses "-h" and "--help", and version uses "-V" and "--version". You can - // safely override "-V" and "-h" to your own arguments, and "--help" and "--version" will still - // be automatically generated for you. - let matches = App::new("MyApp") - // All application settings go here... - - // A simple "Flag" argument example (i.e. "-d") using the builder pattern - .arg(Arg::with_name("debug") - .help("turn on debugging information") - .short("d")) - - // Two arguments, one "Option" argument (i.e. one that takes a value) such - // as "-c some", and one positional argument (i.e. "myapp some_file") - .args(&[ - Arg::with_name("config") - .help("sets the config file to use") - .takes_value(true) - .short("c") - .long("config"), - Arg::with_name("input") - .help("the input file to use") - .index(1) - .required(true) - ]) - - // *Note* the following two examples are convenience methods, if you wish - // to still get the full configurability of Arg::with_name() and the readability - // of arg_from_usage(), you can instantiate a new Arg with Arg::from_usage() and - // still be able to set all the additional properties, just like Arg::with_name() - // - // - // One "Flag" using a usage string - .arg_from_usage("--license 'display the license file'") - - // Two args, one "Positional", and one "Option" using a usage string - .args_from_usage("[output] 'Supply an output file to use' - -i, --int=[IFACE] 'Set an interface to use'") - .get_matches(); - - // Here are some examples of using the arguments defined above. Keep in mind that this is only - // an example, and may be somewhat contrived - // - // First we check if debugging should be on or not - println!("Debugging mode is: {}", if matches.is_present("debug") { "ON" } else { "OFF" }); - - // Next we print the config file we're using, if any was defined with either -c <file> or - // --config <file> - if let Some(config) = matches.value_of("config") { - println!("A config file was passed in: {}", config); - } - - // Let's print the <INPUT> file the user passed in. We can use .unwrap() here becase the arg is - // required, and parsing would have failed if the user forgot it - println!("Using input file: {}", matches.value_of("input").unwrap()); - - // We could continue checking for and using arguments in this manner, such as "license", - // "output", and "interface". Keep in mind that "output" and "interface" are optional, so you - // shouldn't call .unwrap(). Instead, prefer using an 'if let' expression as we did with - // "config" -} |