Command wrappers for cargo xtask pattern

Usage

The main idea is to define commands one of the following ways:

• Single/double dash specifier on arguments

    use std::ffi::OsStr;
  
    #[command]
    struct Echo {
        /// Do not output the trailing newline
        #[arg(single)]
        n: bool,
        /// Enable interpretation fo backslash escapes
        #[arg(single)]
        e: bool,
        /// Display help and exit
        #[arg(double)]
        help: bool,
        /// Display version info and exit
        #[arg(double)]
        version:bool,
        /// The string to echo
        string: OsStr,
    }
  

• Specifier for everything, sensible defaults
  • Defaults:
    • prefix="--"
    • postfix=" "
    • name=IDENT
    • flag is absent
  • Example:

    use std::ffi::OsStr;
    
    #[cmd(name="/bin/echo")]
    struct Echo {
        /// Do not output the trailing newline
        #[cmd::opt(flag, prefix="-", name="n")]
        no_newline: bool,
        /// Enable interpretation fo backslash escapes
        #[cmd::opt(flag, prefix="-", name="e")]
        escape: bool,
        /// Display help and exit
        #[cmd::opt(flag, prefix="--")]
        help: bool,
        /// Display version info and exit
        #[cmd::opt(flag, prefix="--")]
        version: bool,
        /// The string to echo
        string: OsStr,
    }
    

  • Result:

    /bin/echo [-n] [-e] [--help] [--version] STRING