Impl "gocode" subcommand for outputting sample Go code using "gtree" … (

#175)

* Impl "gocode" subcommand for outputting sample Go code using "gtree" package

* nits

* Goパッケージの依存関係リストからツリー生成するGoプログラムを出力

* update README

* update README

.gitignore

@@ -1,4 +1,6 @@
 tmp.md
+go_dependences.txt
+tmp/
 coverage.*
 gtreetest/
 root/

README.md

@@ -126,6 +126,7 @@ COMMANDS:
    mkdir, m           Make directories(and files) from markdown. It is possible to dry run. Let's try 'gtree template | gtree mkdir -e .go -e .md -e Makefile'.
    template, t, tmpl  Output markdown template.
    web, w, www        Open "Tree Maker" in your browser. If it doesn't open, it will display the url.
+   gocode, gc, code   Output a sample Go program calling "gtree" package.
    version, v         Output gtree version.
    help, h            Shows a list of commands or help for one command
 
@@ -737,7 +738,8 @@ func preparePrimate() *gtree.Node {
 
 ---
 
-- The program below converts the result of `find` into a tree.
+#### The program below converts the result of `find` into a tree.
+
 ```go
 package main
 
@@ -817,8 +819,20 @@ func main() {
 
 ```
 
-- Convert `go list -deps ./...` to tree 👉 [link](https://github.com/ddddddO/gtree/blob/master/example/go-list_pipe_programmable-gtree/main.go)
-  - inspired by [nikolaydubina/go-recipes](https://github.com/nikolaydubina/go-recipes#readme) !
+- The above Go program can be output with the command below.
+
+	```console
+	$ gtree gocode
+	```
+
+
+#### Convert `go list -deps ./...` to tree 👉 [link](https://github.com/ddddddO/gtree/blob/master/example/go-list_pipe_programmable-gtree/main.go)
+
+- The above Go program can be output with the command below.
+	```console
+	$ gtree gocode --godeps-to-tree
+	```
+- inspired by [nikolaydubina/go-recipes](https://github.com/nikolaydubina/go-recipes#readme) !
 
 ### *MkdirProgrammably* func
 

cmd/gtree/go_code.go

@@ -0,0 +1,107 @@
+package main
+
+import (
+	"fmt"
+	"strings"
+)
+
+type gocode string
+
+func (g gocode) print() error {
+	_, err := fmt.Print(strings.Trim(string(g), "\n"))
+	return err
+}
+
+func (g gocode) println() error {
+	if err := g.print(); err != nil {
+		return err
+	}
+	_, err := fmt.Println()
+	return err
+}
+
+const findToTree gocode = `
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/ddddddO/gtree"
+)
+
+// $ gtree gocode > find_to_tree.go && go mod init xxx 2>/dev/null && go mod tidy 2>/dev/null && find . -type d -o -type f -print | go run find_to_tree.go
+func main() {
+	var (
+		root *gtree.Node
+		node *gtree.Node
+	)
+	scanner := bufio.NewScanner(os.Stdin)
+	for scanner.Scan() {
+		line := scanner.Text()
+		splited := strings.Split(line, "/")
+
+		for i, s := range splited {
+			if root == nil {
+				root = gtree.NewRoot(s)
+				node = root
+				continue
+			}
+			if i == 0 {
+				continue
+			}
+
+			tmp := node.Add(s)
+			node = tmp
+		}
+		node = root
+	}
+
+	if err := gtree.OutputProgrammably(os.Stdout, root); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+}
+`
+
+const goDependencesToTree gocode = `
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/ddddddO/gtree"
+)
+
+// $ ls | grep go.mod && go list -deps ./path/to/go_dir > go_dependences.txt
+// $ mkdir tmp && cd tmp && gtree gocode --godeps-to-tree > godeps_to_tree.go && go mod init xxx 2>/dev/null && go mod tidy 2>/dev/null && cat ../go_dependences.txt | go run godeps_to_tree.go
+func main() {
+	var (
+		root = gtree.NewRoot("[All Dependencies]")
+		node *gtree.Node
+	)
+	scanner := bufio.NewScanner(os.Stdin)
+	for scanner.Scan() {
+		line := scanner.Text()
+		splited := strings.Split(line, "/")
+
+		for i, s := range splited {
+			if i == 0 {
+				node = root.Add(s)
+				continue
+			}
+			node = node.Add(s)
+		}
+	}
+
+	if err := gtree.OutputProgrammably(os.Stdout, root); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+}
+`

cmd/gtree/main.go

@@ -92,6 +92,13 @@ func main() {
 		},
 	}
 
+	gocodeFlags := []cli.Flag{
+		&cli.BoolFlag{
+			Name:  "godeps-to-tree",
+			Usage: "Output Go program to convert Go package dependency list to tree.",
+		},
+	}
+
 	app := &cli.App{
 		Name:  "gtree",
 		Usage: "This CLI generates directory trees and the directories itself using Markdown.",
@@ -128,6 +135,14 @@ func main() {
 				Before:  notExistArgs,
 				Action:  actionWeb,
 			},
+			{
+				Name:    "gocode",
+				Aliases: []string{"gc", "code"},
+				Usage:   "Output a sample Go program calling \"gtree\" package.",
+				Flags:   gocodeFlags,
+				Before:  notExistArgs,
+				Action:  actionGoCode,
+			},
 			{
 				Name:    "version",
 				Aliases: []string{"v"},
@@ -247,3 +262,11 @@ func actionWeb(c *cli.Context) error {
 
 	return nil
 }
+
+func actionGoCode(c *cli.Context) error {
+	if c.Bool("godeps-to-tree") {
+		return goDependencesToTree.println()
+	}
+
+	return findToTree.println()
+}