Custom type for arguments

app.go

@@ -86,8 +86,8 @@ func (a *App) Run(arguments []string) error {
 	}
 
 	args := context.Args()
-	if len(args) > 0 {
-		name := args[0]
+	if args.Present() {
+		name := args.First()
 		c := a.Command(name)
 		if c != nil {
 			return c.Run(context)

app_test.go

@@ -29,7 +29,7 @@ func TestApp_Run(t *testing.T) {
 
 	app := cli.NewApp()
 	app.Action = func(c *cli.Context) {
-		s = s + c.Args()[0]
+		s = s + c.Args().First()
 	}
 
 	err := app.Run([]string{"command", "foo"})
@@ -76,7 +76,7 @@ func TestApp_CommandWithArgBeforeFlags(t *testing.T) {
 		},
 		Action: func(c *cli.Context) {
 			parsedOption = c.String("option")
-			firstArg = c.Args()[0]
+			firstArg = c.Args().First()
 		},
 	}
 	app.Commands = []cli.Command{command}
@@ -103,7 +103,7 @@ func TestApp_ParseSliceFlags(t *testing.T) {
 			parsedIntSlice = c.IntSlice("p")
 			parsedStringSlice = c.StringSlice("ip")
 			parsedOption = c.String("option")
-			firstArg = c.Args()[0]
+			firstArg = c.Args().First()
 		},
 	}
 	app.Commands = []cli.Command{command}

cli_test.go

@@ -15,7 +15,7 @@ func Example() {
 			ShortName: "a",
 			Usage:     "add a task to the list",
 			Action: func(c *cli.Context) {
-				println("added task: ", c.Args()[0])
+				println("added task: ", c.Args().First())
 			},
 		},
 		{
@@ -23,7 +23,7 @@ func Example() {
 			ShortName: "c",
 			Usage:     "complete a task on the list",
 			Action: func(c *cli.Context) {
-				println("completed task: ", c.Args()[0])
+				println("completed task: ", c.Args().First())
 			},
 		},
 	}

command.go

@@ -43,11 +43,12 @@ func (c Command) Run(ctx *Context) error {
 
 	var err error
 	if firstFlagIndex > -1 {
-		args := ctx.Args()[1:firstFlagIndex]
-		flags := ctx.Args()[firstFlagIndex:]
-		err = set.Parse(append(flags, args...))
+		args := ctx.Args()
+		regularArgs := args[1:firstFlagIndex]
+		flagArgs := args[firstFlagIndex:]
+		err = set.Parse(append(flagArgs, regularArgs...))
 	} else {
-		err = set.Parse(ctx.Args()[1:])
+		err = set.Parse(ctx.Args().Tail())
 	}
 
 	if err != nil {

context.go

@@ -15,6 +15,8 @@ type Context struct {
 	globalSet *flag.FlagSet
 }
 
+type Args []string
+
 // Creates a new context. For use in when invoking an App or Command action.
 func NewContext(app *App, set *flag.FlagSet, globalSet *flag.FlagSet) *Context {
 	return &Context{app, set, globalSet}
@@ -71,8 +73,9 @@ func (c *Context) GlobalIntSlice(name string) []int {
 }
 
 // Returns the command line arguments associated with the context.
-func (c *Context) Args() []string {
-	return c.flagSet.Args()
+func (c *Context) Args() Args {
+	args := Args(c.flagSet.Args())
+	return args
 }
 
 func (c *Context) lookupInt(name string, set *flag.FlagSet) int {
@@ -130,16 +133,29 @@ func (c *Context) lookupBool(name string, set *flag.FlagSet) bool {
 	return false
 }
 
-// Returns the nth argument, or just a blank string
-func (c *Context) GetArg(n int) string {
-	args := c.Args()
-	if len(args) < n {
-		return args[n]
+// Returns the nth argument, or else a blank string
+func (a Args) Get(n int) string {
+	if len(a) > n {
+		return a[n]
 	}
 	return ""
 }
 
-// Returns the first argument, or just a blank string, for convenience
-func (c *Context) FirstArg() string {
-	return c.GetArg(0)
+// Returns the first argument, or else a blank string
+func (a Args) First() string {
+	return a.Get(0)
+}
+
+// Return the rest of the arguments (not the first one)
+// or else an empty string slice
+func (a Args) Tail() []string {
+	if len(a) >= 2 {
+		return []string(a)[1:]
+	}
+	return []string{}
+}
+
+// Checks if there are any arguments present
+func (a Args) Present() bool {
+	return len(a) != 0
 }

help.go

@@ -76,8 +76,8 @@ var helpCommand = Command{
 	Usage:     "Shows a list of commands or help for one command",
 	Action: func(c *Context) {
 		args := c.Args()
-		if len(args) > 0 {
-			ShowCommandHelp(c, args[0])
+		if args.Present() {
+			ShowCommandHelp(c, args.First())
 		} else {
 			ShowAppHelp(c)
 		}