mirror of
https://github.com/clap-rs/clap
synced 2024-12-14 14:52:33 +00:00
33 lines
926 B
Rust
33 lines
926 B
Rust
#![allow(deprecated)] // Can't opt-out of implicit flags until #3405
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use clap::Parser;
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#[derive(Parser, Debug, PartialEq)]
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#[clap(author, version, about, long_about = None)]
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struct Opt {
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// Default parser for `try_from_str` is FromStr::from_str.
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// `impl FromStr for bool` parses `true` or `false` so this
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// works as expected.
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#[clap(long, parse(try_from_str))]
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foo: bool,
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// Of course, this could be done with an explicit parser function.
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#[clap(long, parse(try_from_str = true_or_false), default_value_t)]
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bar: bool,
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// `bool` can be positional only with explicit `parse(...)` annotation
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#[clap(parse(try_from_str))]
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boom: bool,
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}
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fn true_or_false(s: &str) -> Result<bool, &'static str> {
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match s {
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"true" => Ok(true),
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"false" => Ok(false),
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_ => Err("expected `true` or `false`"),
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}
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}
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fn main() {
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let opt = Opt::parse();
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dbg!(opt);
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}
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