Add support for nil flag sets

Makefile

@@ -12,14 +12,14 @@ else
 endif
 
 LUME_VERSION ?= $(shell git describe --tags --always)
-LDFLAGS := ${LDFLAGS} \
+LDFLAGS := $(LDFLAGS) \
-	-X git.kill0.net/chill9/lume/cmd.Version=${LUME_VERSION} \
+	-X git.kill0.net/chill9/lume/cmd.Version=$(LUME_VERSION) \
-	-X git.kill0.net/chill9/lume/cmd.BuildDate=${BUILD_DATE}
+	-X git.kill0.net/chill9/lume/cmd.BuildDate=$(BUILD_DATE)
 
 .PHONY: build
 build:
-	$(Q) go build -o ${EXE} -ldflags="${LDFLAGS}" ./cmd/lume
+	$(Q) go build -o $(EXE) -ldflags="$(LDFLAGS)" ./cmd/lume
 
 .PHONY: clean
 clean:
-	${RM} ${EXE}
+	$(RM) $(EXE)

cmd/command.go

@@ -21,6 +21,7 @@ type Config struct {
 
 type CmdArgs struct {
 	Flags  Flags
+	Args   []string
 	Client *lifx.Client
 	Config Config
 	Name   string

cmd/help.go

@@ -1,7 +1,6 @@
 package lumecmd
 
 import (
-	"flag"
 	"fmt"
 	"sort"
 )
@@ -10,23 +9,16 @@ func NewCmdHelp() Command {
 	return Command{
 		Name:  "help",
 		Func:  HelpCmd,
-		Flags: func() *flag.FlagSet {
-			fs := flag.NewFlagSet("help", flag.ExitOnError)
-
-			return fs
-		}(),
 		Use:   "<command>",
 		Short: "Show help for a command",
 	}
 }
 
 func HelpCmd(args CmdArgs) (int, error) {
-	argv := args.Flags.Args()
+	if len(args.Args) == 0 {
-
-	if len(argv) == 0 {
 		printHelp(commandRegistry)
-	} else if len(argv) >= 1 {
+	} else if len(args.Args) >= 1 {
-		printCmdHelp(argv[0])
+		printCmdHelp(args.Args[0])
 	}
 
 	return ExitSuccess, nil
@@ -63,11 +55,15 @@ func printCmdHelp(name string) error {
 
 	if subCmd.Use != "" {
 		fmt.Printf("usage:\n  lume %s %s\n", subCmd.Name, subCmd.Use)
-		fmt.Println()
+	} else {
+		fmt.Printf("usage:\n  lume %s\n", subCmd.Name)
 	}
 
+	if subCmd.Flags != nil {
+		fmt.Println()
 		fmt.Print("flags:\n")
 		subCmd.Flags.PrintDefaults()
+	}
 
 	return nil
 }

cmd/main.go

@@ -74,6 +74,7 @@ func Main(args []string) (int, error) {
 	cmdArgs := CmdArgs{
 		Client: c,
 		Config: config,
+		Args:   args[2:],
 	}
 
 	cmd, ok := GetCommand(command)
@@ -81,11 +82,14 @@ func Main(args []string) (int, error) {
 		err = fmt.Errorf("lume: '%s' is not lume command. See 'lume help'", command)
 		return ExitFailure, err
 	}
-	fs := cmd.Flags
-	fs.Parse(args[2:])
 
+	fs := cmd.Flags
+	if fs != nil {
+		fs.Parse(args[2:])
 		cmdArgs.Flags = Flags{FlagSet: fs}
+	}
 	cmdArgs.Name = command
+
 	exitCode, err := cmd.Func(cmdArgs)
 	if err != nil {
 		err = fmt.Errorf("fatal: %s", err)