clap/clap_derive/examples/doc_comments.rs
Ed Page 60c9c2e59a docs(derive): Use more-specific traits
This helps to raise visibility of the new derive traits.

I didn't touch ui tests because there were a lot and they didn't seem to
be as high value.
2021-10-12 07:51:11 -05:00

74 lines
2.1 KiB
Rust

//! How to use doc comments in place of `help/long_help`.
use clap::{Parser, Subcommand};
/// A basic example for the usage of doc comments as replacement
/// of the arguments `help`, `long_help`, `about` and `long_about`.
#[derive(Parser, Debug)]
#[clap(name = "basic")]
struct Opt {
/// Just use doc comments to replace `help`, `long_help`,
/// `about` or `long_about` input.
#[clap(short, long)]
first_flag: bool,
/// Split between `help` and `long_help`.
///
/// In the previous case clap is going to present
/// the whole comment both as text for the `help` and the
/// `long_help` argument.
///
/// But if the doc comment is formatted like this example
/// -- with an empty second line splitting the heading and
/// the rest of the comment -- only the first line is used
/// as `help` argument. The `long_help` argument will still
/// contain the whole comment.
///
/// ## Attention
///
/// Any formatting next to empty lines that could be used
/// inside a doc comment is currently not preserved. If
/// lists or other well formatted content is required it is
/// necessary to use the related clap argument with a
/// raw string as shown on the `third_flag` description.
#[clap(short, long)]
second_flag: bool,
#[clap(
short,
long,
long_about = r"This is a raw string.
It can be used to pass well formatted content (e.g. lists or source
code) in the description:
- first example list entry
- second example list entry
"
)]
third_flag: bool,
#[clap(subcommand)]
sub_command: SubCommand,
}
#[derive(Subcommand, Debug)]
#[clap()]
enum SubCommand {
/// The same rules described previously for flags. Are
/// also true for in regards of sub-commands.
First,
/// Applicable for both `about` an `help`.
///
/// The formatting rules described in the comment of the
/// `second_flag` also apply to the description of
/// sub-commands which is normally given through the `about`
/// and `long_about` arguments.
Second,
}
fn main() {
let opt = Opt::parse();
println!("{:?}", opt);
}