mirror of
https://github.com/clap-rs/clap
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71 lines
3.6 KiB
Rust
71 lines
3.6 KiB
Rust
extern crate clap;
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use clap::{App, Arg};
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fn main() {
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// Option arguments are those that take an additional value, such as "-c value". In clap they
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// support three types of specification, those with short() as "-o some", or those with long()
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// as "--option value" or "--option=value"
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//
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// Options also support a multiple setting, which is dicussed in the example below.
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let matches = App::new("MyApp")
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// Regular App configuration goes here...
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// Assume we an application that accepts an input file via the "-i file"
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// or the "--input file" (as wel as "--input=file").
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// Below every setting supported by option arguments is discussed.
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// NOTE: You DO NOT need to specify each setting, only those which apply
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// to your particular case.
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.arg(Arg::new("input")
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.help("the input file to use") // Displayed when showing help info
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.takes_value(true) // MUST be set to true in order to be an "option" argument
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.short("i") // This argument is triggered with "-i"
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.long("input") // This argument is triggered with "--input"
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.multiple(true) // Set to true if you wish to allow multiple occurrences
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// such as "-i file -i other_file -i third_file"
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.required(true) // By default this argument MUST be present
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// NOTE: mutual exclusions take precedence over
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// required arguments
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.requires("config") // Says, "If the user uses "input", they MUST
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// also use this other 'config' arg too"
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// Can also specifiy a list using
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// requires_all(Vec<&str>)
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.mutually_excludes("output") // Opposite of requires(), says "if the
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// user uses -a, they CANNOT use 'output'"
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// also has a mutually_excludes_all(Vec<&str>)
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)
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// NOTE: In order to compile this example, comment out mutually_excludes()
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// and requires() because we have not defined an "output" or "config"
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// argument.
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.get_matches();
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// We can find out whether or not "input" was used
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if matches.is_present("input") {
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println!("An input file was specified");
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}
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// We can also get the value for "input"
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//
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// NOTE: If we specified multiple(), this will only return the _FIRST_
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// occurrence
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if let Some(ref in_file) = matches.value_of("input") {
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println!("An input file: {}", in_file);
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}
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// If we specified the multiple() setting we can get all the values
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if let Some(ref in_v) = matches.values_of("input") {
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for in_file in in_v.iter() {
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println!("An input file: {}", in_file);
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}
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}
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// We can see how many times the option was used with the occurrences_of() method
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//
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// NOTE: Just like with flags, if we did not specify the multiple() setting this will only
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// return 1 no matter how many times the argument was used (unless it wasn't used at all, in
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// in which case 0 is returned)
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println!("The \"input\" argument was used {} times", matches.occurrences_of("input"));
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// Continued program logic goes here...
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}
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