docopt-go和cobra不同，它的CLI参数的解析思路是直接从文档解析。
docopt parses command-line arguments based on a help message. Don't write parser code: a good help message already has all the necessary information in it.
比如:
package main
import (
"fmt"
"github.com/docopt/docopt-go"
"os"
"sort"
)
func main() {
usage := `Naval Fate.
Usage:
naval_fate ship new <name>...
naval_fate ship <name> move <x> <y> [--speed=<kn>]
naval_fate ship shoot <x> <y>
naval_fate mine (set|remove) <x> <y> [--moored|--drifting]
naval_fate -h | --help
naval_fate --version
Options:
-h --help Show this screen.
--version Show version.
--speed=<kn> Speed in knots [default: 10].
--moored Moored (anchored) mine.
--drifting Drifting mine.`
opts, _ := docopt.ParseArgs(usage,os.Args[1:],"v1.0")
// Sort the keys of the options map
var keys []string
for k := range opts {
keys = append(keys, k)
}
sort.Strings(keys)
// Print the option keys and values
for _, k := range keys {
fmt.Printf("%9s %v\n", k, opts[k])
}
}
运行:
$ go run main.go ship myship move 4 4 --speed 12
--drifting false
--help false
--moored false
--speed 12
--version false
<name> [myship]
<x> 4
<y> 4
mine false
move true
new false
remove false
set false
ship true
shoot false
可以发现<x> <y> --speed等都解析出了值.
如果是用cobra，需要调用API定义参数:
// -t <int>
// --times <int>
cmdTimes.Flags().IntVarP(&echoTimes, "times", "t", 1, "times to echo the input")
对比cobra, docopt-go只需要提供一个规范的CLI使用文档就可以了。
docopt-go写一些简单的CLI app还是比较好用的
