Macro cargo::util::command_prelude::value_parser

macro_rules! value_parser {
    ($name:ty) => { ... };
}

Select a [ValueParser] implementation from the intended type

Supported types

• [ValueParserFactory types][ValueParserFactory], including
  • [Native types][ValueParser]: bool, String, OsString, PathBuf
  • [Ranged numeric types][RangedI64ValueParser]: u8, i8, u16, i16, u32, i32, u64, i64
• [ValueEnum types][crate::ValueEnum]
• From<OsString> types and From<&OsStr> types
• From<String> types and From<&str> types
• FromStr types, including usize, isize

Example

Usage:

let mut cmd = clap::Command::new("raw")
    .arg(
        clap::Arg::new("output")
            .value_parser(clap::value_parser!(PathBuf))
            .required(true)
    );

let m = cmd.try_get_matches_from_mut(["cmd", "file.txt"]).unwrap();
let port: &PathBuf = m.get_one("output")
    .expect("required");
assert_eq!(port, Path::new("file.txt"));

Example mappings:

// Built-in types
let parser = clap::value_parser!(String);
assert_eq!(format!("{parser:?}"), "ValueParser::string");
let parser = clap::value_parser!(std::ffi::OsString);
assert_eq!(format!("{parser:?}"), "ValueParser::os_string");
let parser = clap::value_parser!(std::path::PathBuf);
assert_eq!(format!("{parser:?}"), "ValueParser::path_buf");
clap::value_parser!(u16).range(3000..);
clap::value_parser!(u64).range(3000..);

// FromStr types
let parser = clap::value_parser!(usize);
assert_eq!(format!("{parser:?}"), "_AnonymousValueParser(ValueParser::other(usize))");

// ValueEnum types
clap::value_parser!(ColorChoice);