spruce/internal/cmd/cmd.go

package cmd

import (
	"flag"
	"fmt"
	"strings"
)

type Runner interface {
	Parse([]string) error
	Name() string
	Run() error
}

func usageFunc(name, summary string, flagset *flag.FlagSet) func() {
	return func() {
		var builder strings.Builder

		fmt.Fprintf(&builder, "SUMMARY:\n  %s - %s\n\nUSAGE:\n  spruce %s [flags]\n\nFLAGS:", name, summary, name)

		flagset.VisitAll(func(f *flag.Flag) {
			fmt.Fprintf(&builder, "\n  -%s, --%s\n        %s", f.Name, f.Name, f.Usage)
		})

		builder.WriteString("\n")

		w := flag.CommandLine.Output()

		fmt.Fprint(w, builder.String())
	}
}