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][std::convert::From] and [From<&OsStr> types][std::convert::From]
• [From<String> types][std::convert::From] and [From<&str> types][std::convert::From]
• [FromStr types][std::str::FromStr], including usize, isize

Example

Usage:

# use clap_builder as clap;
# use std::path::PathBuf;
# use std::path::Path;
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:

# use clap_builder as clap;
# use clap::ColorChoice;
// 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);