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//! Several ways of creating more fancier flags from primitive components
//! In practice for "verbose" you'd use a builder pattern and define the variable only once, for
//! trim on/off you need to define the variables but they can be in a local scope with {}
use bpaf::*;
#[derive(Debug, Clone, Copy)]
enum Trim {
On,
Off,
}
fn main() {
// program takes one or more -v or --verbose flags, more flags = higher verbosity.
// parser handles number and produces a single flag.
//
// let's create it without using any single purpose magical functions
// Let's staty by creating a simple parser that handles a single -v / --verbose
// and fails otherwise;
let verbose = short('v').long("verbose").req_flag(());
// Try to apply the inner parser as many times as it succeeds, return the number
let verbose = verbose.count();
// And add a simple sanity checker.
// By this time when this parser succeeds - it will contain verbosity in 0..3 range, inclusive.
let verbose = verbose.guard(|&x| x <= 3, "it doesn't get any more verbose than 3");
// program takes --trimor --no-trimflag, but not both at once. If none is given -
// fallback value is to disable trimming. Trim enum is set accordingly
// this flag succeeds iff --no-trim is given and produces Trim::Off
let trim_off = long("no-trim").req_flag(Trim::Off);
// this flag handles two remaining cases: --trim is given (Trim::On) an fallback (Trim::Off)
let trim_on = long("trim").flag(Trim::On, Trim::Off);
// combination of previous two.
// if trim_off succeeds - trim_on never runs, otherwise trim_on tries to handle the remaining
// case before falling back to Trim:Off.
// If both --trim and --no-trim are given trim_off succeeds, trim_off never runs and --trim
// remains unused - parser fails
let trim = construct!([trim_off, trim_on]);
let parser = construct!(verbose, trim);
let opt = parser.to_options().run();
println!("{:#?}", opt);
}