feat: parse all Go CLIs with flaggy; dump bash complete. (#36)

stdlib flag dropped --hop after the query. One wrapper in internal/cli,
source <(./bin/cli/complete.go bash). Gitea #34.

internal/mdleaves/args.go

@@ -0,0 +1,41 @@
+package mdleaves
+
+import (
+	"github.com/eSlider/2dph/internal/cli"
+	"github.com/integrii/flaggy"
+)
+
+type CLI struct {
+	Root    string
+	Files   string
+	JSONOut bool
+}
+
+func Parser() *flaggy.Parser {
+	c := CLI{Root: "."}
+	return Bind(&c)
+}
+
+func Bind(c *CLI) *flaggy.Parser {
+	if c.Root == "" {
+		c.Root = "."
+	}
+	p := cli.New("markdown-import")
+	p.Description = "split markdown H2 leafs"
+	p.Bool(&c.JSONOut, "", "json", "JSON output")
+	p.String(&c.Files, "", "files", "comma-separated paths")
+	p.AddPositionalValue(&c.Root, "dir", 1, false, "markdown root")
+	return p
+}
+
+func ParseArgs(args []string) (CLI, error) {
+	c := CLI{Root: "."}
+	p := Bind(&c)
+	if err := cli.Parse(p, args); err != nil {
+		return c, err
+	}
+	if extra := cli.Query("", p.TrailingArguments); extra != "" && c.Root == "." {
+		c.Root = extra
+	}
+	return c, nil
+}