bpaf 0.4.3

A simple Command Line Argument Parser with parser combinators
Documentation 
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//! A somewhat comprehensive example of a typical `bpaf` usage.

use bpaf::*;
use std::path::PathBuf;

#[allow(dead_code)]
#[derive(Debug, Clone)]
struct Out {
    debug: bool,
    verbose: usize,
    speed: f64,
    output: PathBuf,
    nb_cars: u32,
    files_to_process: Vec<PathBuf>,
}

fn main() {
    // A flag, true if used in the command line. Can be required, this one is optional
    let debug: Parser<bool> = short('d')
        .long("debug")
        .help("Activate debug mode")
        .switch();

    // number of occurrences of the v/verbose flag capped at 3
    let verbose: Parser<usize> = short('v')
        .long("verbose")
        .help("Increase the verbosity\nYou can specify it up to 3 times\neither as -v -v -v or as -vvv")
        .req_flag(())
        .many()
        .map(|xs| xs.len())
        .guard(|&x| x <= 3, "It doesn't get any more verbose than this");

    // an argument, parsed and with default value
    let speed: Parser<f64> = short('s')
        .long("speed")
        .help("Set speed")
        .argument("SPEED")
        .from_str()
        .fallback(42.0);

    let output: Parser<PathBuf> = short('o')
        .long("output")
        .help("output file")
        .argument_os("OUTPUT")
        .map(PathBuf::from);

    // no magical name transmogrifications.
    let nb_cars: Parser<u32> = short('n').long("nb-cars").argument("N").from_str();

    // a parser that consumes one argument
    let file_to_proces: Parser<PathBuf> = short('f')
        .long("file")
        .help("File to process")
        .argument_os("FILE")
        .map(PathBuf::from);
    let files_to_process: Parser<Vec<PathBuf>> = file_to_proces.many();

    // packing things in a struct assumes parser for each field is in scope.
    let parser = construct!(Out {
        debug,
        verbose,
        speed,
        output,
        nb_cars,
        files_to_process
    });
    let opt = Info::default().for_parser(parser).run();
    println!("{:#?}", opt);
}