Arg, a struct config parser

package main

import (
    "gitee.com/wick.zt/arg-go"
)

type conf struct {
    Host     string `arg:"--host,<127.0.0.1>,:redis server host"`
    Port     uint16 `arg:"-p,--port,<6379>,:redis server port"`
    Password string `arg:"--password,:redis connection password"`
    Dryrun   bool   `arg:"-d,--dryrun,:do not act if set"`
    Negative bool   `arg:"-n,--negative,<true>,:test negative bool value"`
    Skip     int    // arg parser will skip this field
    Operate  string `arg:"-x,+r,:operation to act on server"`
}

func main() {
    c := &conf{}
    if err := arg.Prepare(c); err != nil {
        panic(err)
    }
    verbose := arg.NewFlag("Verbose", 'v', "verbose", "show debug messages", false)
    if err := arg.AddFlag(verbose, arg.OrderPreferred, func(interface{}) error {
        fmt.Println("set log level to debug")
    }); err != nil {
        panic(err)
    }
    if err := arg.Parse(); err != nil {
        panic(err)
    }
    fmt.Printf("Config: %+v\n", c) // ... use conf `c`
}

// $ main --password secret -x op
// Config: &{Host:127.0.0.1 Port:6379 Password:secret Dryrun:false Negative:true Skip:0 Operate:op}

$ main --help
Usage of main:
    main [-h] [-d] [--host Host] -x Operate [--password Password] [-p Port]

Flags:
    -h,--help
        show this message and exit
    -v,--verbose
        show debug messages

Options:
    -d,--dryrun
        do not act if set
    --host HOST
        redis server host (default: 127.0.0.1)
    -n,--negative
        test negative bool value (default: true)
    -x OPERATE
        operation to act on server (required)
    --password PASSWORD
        redis connection password
    -p,--port PORT
        redis server port (default: 6379)