mirror of
https://github.com/clap-rs/clap
synced 2024-12-14 06:42:33 +00:00
d840d5650e
Before #2005, `Clap` was a special trait that derived all clap traits it detected were relevant (including an enum getting both `ArgEnum`, `Clap`, and `Subcommand`). Now, we have elevated `Clap`, `Args`, `Subcommand`, and `ArgEnum` to be user facing but the name `Clap` isn't very descriptive. This also helps further clarify the relationships so a crate providing an item to be `#[clap(flatten)]` or `#[clap(subcommand)]` is more likely to choose the needed trait to derive. Also, my proposed fix fo #2785 includes making `App` attributes almost exclusively for `Clap`. Clarifying the names/roles will help communicate this. For prior discussion, see #2583
54 lines
1.6 KiB
Rust
54 lines
1.6 KiB
Rust
//! Somewhat complex example of usage of #[derive(Parser)].
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use clap::Parser;
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#[derive(Parser, Debug)]
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#[clap(name = "example")]
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/// An example of clap_derive usage.
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struct Opt {
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// A flag, true if used in the command line.
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#[clap(short, long)]
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/// Activate debug mode
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debug: bool,
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// An argument of type float, with a default value.
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#[clap(short, long, default_value = "42")]
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/// Set speed
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speed: f64,
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// Needed parameter, the first on the command line.
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/// Input file
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input: String,
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// An optional parameter, will be `None` if not present on the
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// command line.
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/// Output file, stdout if not present
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output: Option<String>,
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// An optional parameter with optional value, will be `None` if
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// not present on the command line, will be `Some(None)` if no
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// argument is provided (i.e. `--log`) and will be
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// `Some(Some(String))` if argument is provided (e.g. `--log
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// log.txt`).
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#[clap(long)]
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#[allow(clippy::option_option)]
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/// Log file, stdout if no file, no logging if not present
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log: Option<Option<String>>,
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// An optional list of values, will be `None` if not present on
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// the command line, will be `Some(vec![])` if no argument is
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// provided (i.e. `--optv`) and will be `Some(Vec<String>)` if
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// argument list is provided (e.g. `--optv a b c`).
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#[clap(long)]
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optv: Option<Vec<String>>,
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// Skipped option: it won't be parsed and will be filled with the
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// default value for its type (in this case it'll be an empty string).
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#[clap(skip)]
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skipped: String,
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}
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fn main() {
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let opt = Opt::parse();
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println!("{:?}", opt.skipped);
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}
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