mirror of
https://github.com/clap-rs/clap
synced 2024-12-14 23:02:31 +00:00
67 lines
2.3 KiB
Rust
67 lines
2.3 KiB
Rust
// You can use clap's `ArgMatches::value_of_t` method with a custom enum
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// by implementing the std::str::FromStr trait which is very straight forward.
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// There are three ways to do this, for simple enums
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// meaning those that don't require 'pub' or any '#[derive()]' directives you can use clap's
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// simple_enum! macro. For those that require 'pub' or any '#[derive()]'s you can use clap's
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// arg_enum! macro. The third way is to implement std::str::FromStr manually.
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//
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// In most circumstances using either simple_enum! or arg_enum! is fine.
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//
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// In the following example we will create two enums using macros, assign a positional argument
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// that accepts only one of those values, and use clap to parse the argument.
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// Add clap like normal
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use clap::{arg_enum, App, Arg};
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// Using arg_enum! is more like traditional enum declarations
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//
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// **NOTE:** Only bare variants are supported
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arg_enum! {
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#[derive(Debug)]
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pub enum Oof {
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Rab,
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Zab,
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Xuq
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}
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}
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arg_enum! {
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#[derive(Debug)]
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enum Foo {
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Bar,
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Baz,
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Qux
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}
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}
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fn main() {
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// Create the application like normal
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let enum_vals = ["fast", "slow"];
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let m = App::new("myapp")
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// Use a single positional argument that is required
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.arg(Arg::from("<foo> 'The Foo to use'").possible_values(&Foo::variants()))
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.arg(
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Arg::from("<speed> 'The speed to use'")
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// You can define a list of possible values if you want the values to be
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// displayed in the help information. Whether you use possible_values() or
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// not, the valid values will ALWAYS be displayed on a failed parse.
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.possible_values(&enum_vals),
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)
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// For the second positional, lets not use possible_values() just to show the difference
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.arg("<oof> 'The Oof to use'")
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.get_matches();
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// Note that you don't have to specify the type since rustc can infer it for you
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let t = m.value_of_t("foo").unwrap_or_else(|e| e.exit());
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let t2: Oof = m.value_of_t("oof").unwrap_or_else(|e| e.exit());
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// Now we can use our enum like normal.
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match t {
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Foo::Bar => println!("Found a Bar"),
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Foo::Baz => println!("Found a Baz"),
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Foo::Qux => println!("Found a Qux"),
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}
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// Since our Oof derives Debug, we can do this:
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println!("Oof: {:?}", t2);
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}
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