53 lines
887 B
Go
53 lines
887 B
Go
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package main
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import (
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"bytes"
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"flag"
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"fmt"
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"io"
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"text/tabwriter"
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)
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func optionTable(w io.Writer, rows [][]string) {
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tw := tabwriter.NewWriter(w, 2, 4, 2, ' ', 0)
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for _, row := range rows {
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for i, cell := range row {
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if i > 0 {
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tw.Write([]byte("\t"))
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}
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tw.Write([]byte(cell))
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}
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tw.Write([]byte("\n"))
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}
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tw.Flush()
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}
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func usageFor(fs *flag.FlagSet, usage string) func() {
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return func() {
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var b bytes.Buffer
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b.WriteString("Usage:\n " + usage + "\n")
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var options [][]string
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fs.VisitAll(func(f *flag.Flag) {
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var dash = "-"
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if len(f.Name) > 1 {
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dash = "--"
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}
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var opt = " " + dash + f.Name
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if f.DefValue != "false" {
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opt += "=" + f.DefValue
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}
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options = append(options, []string{opt, f.Usage})
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})
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if len(options) > 0 {
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b.WriteString("\nOptions:\n")
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optionTable(&b, options)
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}
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fmt.Println(b.String())
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}
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}
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