Add help menu

cmd/test.go

@@ -0,0 +1,46 @@
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"go.fifitido.net/cmd"
+)
+
+var root = cmd.NewRoot(
+	cmd.WithShortDescription("Example command"),
+	cmd.WithLongDescription(`An example command to show how to use go.fifitido.net/cmd
+
+this example is just a simple hello world program to show
+the basics of the library.`),
+	cmd.WithSubcommand(subcmd),
+	cmd.WithArgument("name", false),
+	cmd.WithRunFunc(func(args []string) {
+		if len(args) == 0 {
+			fmt.Println("Hello World!")
+		} else {
+			fmt.Printf("Hello %s!\n", args[0])
+		}
+	}),
+)
+
+var subcmd = cmd.New(
+	"test",
+	cmd.WithShortDescription("Example command"),
+	cmd.WithLongDescription(`An example command to show how to use go.fifitido.net/cmd
+
+this example is just a simple hello world program to show
+the basics of the library.`),
+	cmd.WithArgument("name", false),
+	cmd.WithRunFunc(func(args []string) {
+		if len(args) == 0 {
+			fmt.Println("Hello World!")
+		} else {
+			fmt.Printf("Hello %s!\n", args[0])
+		}
+	}),
+)
+
+func main() {
+	root.Execute(os.Args)
+}

command.go

@@ -1,20 +1,22 @@
 package cmd
 
-import "go.fifitido.net/cmd/flags"
+import (
+	"os"
+	"path/filepath"
 
-type RunFunc func(args []string)
-type RunErrFunc func(args []string) error
+	"go.fifitido.net/cmd/flags"
+)
 
 type Command struct {
 	Name             string
 	ShortDescription string
 	LongDescription  string
-	Aliases          []string
-	Arguments        []*Argument
-	Flags            []flags.Flag
-	Subcommands      []*Command
-	Run              RunFunc
-	RunE             RunErrFunc
+	aliases          []string
+	arguments        []*Argument
+	flags            []flags.Flag
+	subcommands      []*Command
+	parent           *Command
+	run              func(args []string)
 	isRoot           bool
 }
 
@@ -36,36 +38,53 @@ func (c *Command) ApplyOptions(options ...Option) {
 	}
 }
 
+func (c *Command) CommandPath() string {
+	if c.parent == nil {
+		return filepath.Base(os.Args[0])
+	}
+
+	return c.parent.CommandPath() + " " + c.Name
+}
+
+func (c *Command) CanRun() bool {
+	return c.run != nil
+}
+
+func (c *Command) Run(args []string) {
+	c.run(args)
+}
+
 func (c *Command) Execute(args []string) {
 	if c.isRoot {
 		args = args[1:]
 	}
 
 	if len(args) > 0 {
-		for _, subcommand := range c.Subcommands {
+		for _, subcommand := range c.subcommands {
 			if subcommand.Name == args[0] {
 				subcommand.Execute(args[1:])
 				return
 			}
 
-			for _, alias := range subcommand.Aliases {
+			for _, alias := range subcommand.aliases {
 				if alias == args[0] {
 					subcommand.Execute(args[1:])
 					return
 				}
 			}
 		}
+
+		// TODO: remove when done with flag parsing
+		if args[0] == "--help" {
+			c.ShowHelp()
+			return
+		}
 	}
 
-	if c.Run != nil {
+	if c.CanRun() {
 		c.Run(args)
 		return
 	}
 
-	if c.RunE != nil {
-		if err := c.RunE(args); err != nil {
-			panic(err)
-		}
-		return
-	}
+	c.ShowHelp()
 }

help.go

@@ -0,0 +1,53 @@
+package cmd
+
+import (
+	"fmt"
+)
+
+func (c *Command) ShowHelp() {
+	cmdPath := c.CommandPath()
+
+	fmt.Println(c.LongDescription)
+	fmt.Println()
+	fmt.Println("Usage: ")
+	fmt.Printf("  %s ", cmdPath)
+
+	if len(c.subcommands) > 0 {
+		if c.CanRun() {
+			fmt.Print("[command] ")
+		} else {
+			fmt.Print("<command> ")
+		}
+	}
+
+	fmt.Println("[flags]")
+
+	if len(c.subcommands) > 0 {
+		fmt.Println()
+
+		if c.isRoot {
+			fmt.Println("Available commands:")
+		} else {
+			fmt.Println("Available subcommands:")
+		}
+
+		for _, s := range c.subcommands {
+			fmt.Println("  " + s.Name + "    " + s.ShortDescription)
+		}
+	}
+
+	fmt.Println()
+	fmt.Println("Available flags:")
+
+	for _, s := range c.flags {
+		fmt.Println("  " + s.Name() + "    " + s.Description())
+	}
+
+	fmt.Println("  -h, --help       Show the help menu")
+	fmt.Println("  -v, --version    Show the app version")
+
+	if len(c.subcommands) > 0 {
+		fmt.Println()
+		fmt.Println("Run 'go-cli <command> --help' for more information about a command.")
+	}
+}

option.go

@@ -18,48 +18,60 @@ func WithLongDescription(s string) Option {
 
 func WithArgument(name string, required bool) Option {
 	return func(c *Command) {
-		c.Arguments = append(c.Arguments, &Argument{name, required})
+		c.arguments = append(c.arguments, &Argument{name, required})
 	}
 }
 
 func WithArguments(args []*Argument) Option {
 	return func(c *Command) {
-		c.Arguments = append(c.Arguments, args...)
+		c.arguments = append(c.arguments, args...)
 	}
 }
 
 func WithFlag(f flags.Flag) Option {
 	return func(c *Command) {
-		c.Flags = append(c.Flags, f)
+		c.flags = append(c.flags, f)
 	}
 }
 
 func WithFlags(fs []flags.Flag) Option {
 	return func(c *Command) {
-		c.Flags = append(c.Flags, fs...)
+		c.flags = append(c.flags, fs...)
 	}
 }
 
 func WithSubcommand(s *Command) Option {
 	return func(c *Command) {
-		c.Subcommands = append(c.Subcommands, s)
+		c.subcommands = append(c.subcommands, s)
+		s.parent = c
 	}
 }
 
 func WithSubcommands(ss []*Command) Option {
 	return func(c *Command) {
-		c.Subcommands = append(c.Subcommands, ss...)
+		c.subcommands = append(c.subcommands, ss...)
 	}
 }
 
-func WithRunFunc(r RunFunc) Option {
+func WithParent(p *Command) Option {
 	return func(c *Command) {
-		c.Run = r
+		c.parent = p
+		p.subcommands = append(p.subcommands, c)
 	}
 }
 
-func WithRunErrFunc(r RunErrFunc) Option {
+func WithRunFunc(r func(args []string)) Option {
 	return func(c *Command) {
-		c.RunE = r
+		c.run = r
+	}
+}
+
+func WithRunErrFunc(r func(args []string) error) Option {
+	return func(c *Command) {
+		c.run = func(args []string) {
+			if err := r(args); err != nil {
+				panic(err)
+			}
+		}
 	}
 }