Allow running python kittens via the kitten binary

It just delegates to kitty +kitten automatically

Author: kovidgoyal

tools/cmd/main.go

@@ -3,12 +3,17 @@
 package main
 
 import (
+	"fmt"
 	"os"
+	"path/filepath"
+	"strings"
 
 	"github.com/kovidgoyal/kitty/kittens/ssh"
 	"github.com/kovidgoyal/kitty/tools/cli"
 	"github.com/kovidgoyal/kitty/tools/cmd/completion"
 	"github.com/kovidgoyal/kitty/tools/cmd/tool"
+	"github.com/kovidgoyal/kitty/tools/utils"
+	"golang.org/x/sys/unix"
 )
 
 func KittenMain(args ...string) {
@@ -24,13 +29,26 @@ func KittenMain(args ...string) {
 	root.HelpText = "kitten serves as a launcher for running individual kittens. Each kitten can be run as :code:`kitten command`. The list of available kittens is given below."
 	root.Usage = "command [command options] [command args]"
 	root.Run = func(cmd *cli.Command, args []string) (int, error) {
-		cmd.ShowHelp()
-		return 0, nil
+		if len(args) == 0 {
+			cmd.ShowHelp()
+			return 0, nil
+		}
+		if strings.HasSuffix(args[0], ".py") {
+			exe := utils.KittyExe()
+			if !filepath.IsAbs(exe) {
+				exe = utils.Which(exe)
+			}
+			if err := unix.Exec(exe, append([]string{filepath.Base(exe), "+kitten"}, args...), os.Environ()); err != nil {
+				return 1, fmt.Errorf("failed to run python kitten: %s as could not run kitty executable, with error: %w", args[0], err)
+			}
+		}
+		return 1, fmt.Errorf(":yellow:`%s` is not a known kitten. Use --help to get a list of known kittens.", args[0])
 	}
 
 	tool.KittyToolEntryPoints(root)
 	completion.EntryPoint(root)
 
+	root.SubCommandIsOptional = true
 	root.Exec(args...)
 }