Add nested commands

acmd.go

@@ -44,7 +44,7 @@ type Command struct {
 	Do func(ctx context.Context, args []string) error
 
 	// subcommands of the command.
-	subcommands []Command
+	Subcommands []Command
 }
 
 // Config for the runner.
@@ -116,8 +116,7 @@ func (r *Runner) init() error {
 	cmds := r.cmds
 	r.rootCmd = Command{
 		Name:        "root",
-		Do:          nopFunc,
-		subcommands: cmds,
+		Subcommands: cmds,
 	}
 	if err := validateCommand(r.rootCmd); err != nil {
 		return err
@@ -146,17 +145,21 @@ func (r *Runner) init() error {
 		return cmds[i].Name < cmds[j].Name
 	})
 
-	r.rootCmd.subcommands = cmds
+	r.rootCmd.Subcommands = cmds
+	r.rootCmd.Do = rootDo(r.cfg, cmds)
 
 	return nil
 }
 
 func validateCommand(cmd Command) error {
-	cmds := cmd.subcommands
+	cmds := cmd.Subcommands
 
 	switch {
 	case cmd.Do == nil && len(cmds) == 0:
-		return fmt.Errorf("command %q function cannot be nil", cmd.Name)
+		return fmt.Errorf("command %q function cannot be nil or must have subcommands", cmd.Name)
+
+	case cmd.Do != nil && len(cmds) != 0:
+		return fmt.Errorf("command %q function cannot be set and have subcommands", cmd.Name)
 
 	case cmd.Name == "help" || cmd.Name == "version":
 		return fmt.Errorf("command %q is reserved", cmd.Name)
@@ -202,23 +205,46 @@ func (r *Runner) Run() error {
 	if r.errInit != nil {
 		return fmt.Errorf("acmd: cannot init runner: %w", r.errInit)
 	}
-	if err := run(r.ctx, r.cfg, r.rootCmd.subcommands, r.args); err != nil {
+	if err := r.rootCmd.Do(r.ctx, r.args); err != nil {
 		return fmt.Errorf("acmd: cannot run command: %w", err)
 	}
 	return nil
 }
 
-func run(ctx context.Context, cfg Config, cmds []Command, args []string) error {
-	selected, params := args[0], args[1:]
+func rootDo(cfg Config, cmds []Command) func(ctx context.Context, args []string) error {
+	return func(ctx context.Context, args []string) error {
+		cmds, args := cmds, args
+		for {
+			selected, params := args[0], args[1:]
+
+			var found bool
+			for _, c := range cmds {
+				if selected != c.Name && selected != c.Alias {
+					continue
+				}
+
+				// go deeper into subcommands
+				if c.Do == nil {
+					if len(params) == 0 {
+						return errors.New("no args for subcmd provided")
+					}
+					cmds, args = c.Subcommands, params
+					found = true
+					break
+				}
+				return c.Do(ctx, params)
+			}
 
-	for _, c := range cmds {
-		if selected == c.Name || selected == c.Alias {
-			return c.Do(ctx, params)
+			if !found {
+				return errNotFoundAndSuggest(cfg.Output, selected, cmds)
+			}
 		}
 	}
+}
 
+func errNotFoundAndSuggest(w io.Writer, selected string, cmds []Command) error {
 	if suggestion := suggestCommand(selected, cmds); suggestion != "" {
-		fmt.Fprintf(cfg.Output, "%q is not a subcommand, did you mean %q?\n", selected, suggestion)
+		fmt.Fprintf(w, "%q is not a subcommand, did you mean %q?\n", selected, suggestion)
 	}
 	return fmt.Errorf("no such command %q", selected)
 }

acmd_test.go

@@ -2,12 +2,67 @@ package acmd
 
 import (
 	"bytes"
+	"context"
+	"fmt"
 	"os"
 	"sort"
 	"strings"
 	"testing"
+	"time"
 )
 
+func TestRunner(t *testing.T) {
+	buf := &bytes.Buffer{}
+
+	cmds := []Command{
+		{
+			Name:        "test",
+			Description: "some test command",
+			Subcommands: []Command{
+				{
+					Name: "foo",
+					Subcommands: []Command{
+						{
+							Name: "for", Do: func(ctx context.Context, args []string) error {
+								fmt.Fprint(buf, "for")
+								return nil
+							},
+						},
+					},
+				},
+				{
+					Name: "bar",
+					Do: func(ctx context.Context, args []string) error {
+						fmt.Fprint(buf, "bar")
+						return nil
+					},
+				},
+			},
+		},
+		{
+			Name:        "status",
+			Description: "status command gives status of the state",
+			Do: func(ctx context.Context, args []string) error {
+				return nil
+			},
+		},
+	}
+	r := RunnerOf(cmds, Config{
+		Args:           []string{"test", "foo", "for"},
+		AppName:        "acmd_test_app",
+		AppDescription: "acmd_test_app is a test application.",
+		Version:        time.Now().String(),
+		Output:         buf,
+	})
+
+	if err := r.Run(); err != nil {
+		t.Fatal(err)
+	}
+	if got := buf.String(); got != "for" {
+		t.Fatalf("want %q got %q", "for", got)
+	}
+}
+
 func TestRunnerMustSetDefaults(t *testing.T) {
 	cmds := []Command{{Name: "foo", Do: nopFunc}}
 	r := RunnerOf(cmds, Config{})
@@ -34,7 +89,7 @@ func TestRunnerMustSetDefaults(t *testing.T) {
 	}
 
 	gotCmds := map[string]struct{}{}
-	for _, c := range r.rootCmd.subcommands {
+	for _, c := range r.rootCmd.Subcommands {
 		gotCmds[c.Name] = struct{}{}
 	}
 	if _, ok := gotCmds["help"]; !ok {
@@ -95,6 +150,18 @@ func TestRunnerInit(t *testing.T) {
 			cmds:       []Command{{Name: "foo%", Do: nil}},
 			wantErrStr: `command "foo%" function cannot be nil`,
 		},
+		{
+			cmds:       []Command{{Name: "foo", Do: nil}},
+			wantErrStr: `command "foo" function cannot be nil or must have subcommands`,
+		},
+		{
+			cmds: []Command{{
+				Name:        "foobar",
+				Do:          nopFunc,
+				Subcommands: []Command{{Name: "nested"}},
+			}},
+			wantErrStr: `command "foobar" function cannot be set and have subcommands`,
+		},
 		{
 			cmds: []Command{{Name: "foo", Do: nopFunc}},
 			cfg: Config{
@@ -183,12 +250,12 @@ func TestRunner_suggestCommand(t *testing.T) {
 			Args:   tc.args,
 			Output: buf,
 		})
-		if err := r.Run(); err == nil {
-			t.Fatal()
+		if err := r.Run(); err != nil && !strings.Contains(err.Error(), "no such command") {
+			t.Fatal(err)
 		}
 
 		if got := buf.String(); got != tc.want {
-			t.Logf("want %q got %q", tc.want, got)
+			t.Fatalf("want %q got %q", tc.want, got)
 		}
 	}
 }

example_test.go

@@ -194,3 +194,40 @@ func ExampleAutosuggestion() {
 
 	// Output: "baz" is not a subcommand, did you mean "bar"?
 }
+
+func ExampleNestedCommands() {
+	testOut := os.Stdout
+	testArgs := []string{"foo", "qux"}
+
+	cmds := []acmd.Command{
+		{
+			Name: "foo",
+			Subcommands: []acmd.Command{
+				{Name: "bar", Do: nopFunc},
+				{Name: "baz", Do: nopFunc},
+				{
+					Name: "qux",
+					Do: func(ctx context.Context, args []string) error {
+						fmt.Fprint(testOut, "qux")
+						return nil
+					},
+				},
+			},
+		},
+		{Name: "boom", Do: nopFunc},
+	}
+
+	r := acmd.RunnerOf(cmds, acmd.Config{
+		AppName:        "acmd-example",
+		AppDescription: "Example of acmd package",
+		Version:        "the best v0.x.y",
+		Output:         testOut,
+		Args:           testArgs,
+	})
+
+	if err := r.Run(); err != nil {
+		panic(err)
+	}
+
+	// Output: qux
+}