add markdwon formatter

lib/st.go

@@ -110,3 +110,12 @@ func PlainTextFormatter(writer io.Writer, header []string, data [][]string) {
 	table.AppendBulk(data)
 	table.Render()
 }
+
+func MarkdownTableFormatter(writer io.Writer, header []string, data [][]string) {
+	table := tablewriter.NewWriter(writer)
+	table.SetHeader(header)
+	table.SetBorders(tablewriter.Border{Left: true, Top: false, Right: true, Bottom: false})
+	table.SetCenterSeparator("|")
+	table.AppendBulk(data)
+	table.Render()
+}

lib/st_test.go

@@ -80,3 +80,30 @@ func TestPlainTextFromatter(t *testing.T) {
 		t.Errorf("expected != actual\n%s\n", diff)
 	}
 }
+
+func TestMarkdownTableFromatter(t *testing.T) {
+	stdout := new(bytes.Buffer)
+	st := St{
+		Formatter: MarkdownTableFormatter,
+
+		Count:  true,
+		Min:    true,
+		Max:    true,
+		Sum:    true,
+		Mean:   true,
+		Stddev: true,
+	}
+
+	for _, v := range []float64{0, 1, 2, 3, 4, 5, 6, 7, 8, 9} {
+		st.Process(v)
+	}
+	st.Output(stdout)
+
+	expected := `| N  | MIN | MAX | SUM | MEAN |       STDDEV       |
+|----|-----|-----|-----|------|--------------------|
+| 10 |   0 |   9 |  45 |  4.5 | 3.0276503540974917 |
+`
+	if diff := cmp.Diff(expected, stdout.String()); diff != "" {
+		t.Errorf("expected != actual\n%s\n", diff)
+	}
+}

main.go

@@ -21,6 +21,7 @@ type options struct {
 	Mean     bool   `short:"m" long:"mean" description:"mean"`
 	Stddev   bool   `long:"sd" description:"standard deviation"`
 	Vatiance bool   `long:"variance" description:"variance"`
+	Markdown bool   `long:"markdown" description:"markdown table format"`
 }
 
 func main() {
@@ -35,8 +36,13 @@ func main() {
 		os.Exit(1)
 	}
 
+	f := st.PlainTextFormatter
+	if opts.Markdown {
+		f = st.MarkdownTableFormatter
+	}
+
 	s := st.St{
-		Formatter: st.PlainTextFormatter,
+		Formatter: f,
 
 		Count:    opts.Count,
 		Min:      opts.Min,