Merge pull request #124 from kchason/custom-help-text

Custom Help Text

.gitignore

@@ -0,0 +1,4 @@
+# IDE Settings
+/.idea
+/.vscode
+/.vs

examples/basic/main.go

@@ -38,6 +38,7 @@ func main() {
 		flagSet.SizeVarP(&testOptions.fileSize, "max-size", "ms", "", "max file size"),
 		flagSet.DurationVar(&testOptions.duration, "timeout", time.Hour, "timeout"),
 	)
+	flagSet.SetCustomHelpText("EXAMPLE USAGE:\ngo run ./examples/basic [OPTIONS]")
 
 	if err := flagSet.Parse(); err != nil {
 		log.Fatal(err)

goflags.go

@@ -25,6 +25,7 @@ type FlagSet struct {
 	CaseSensitive  bool
 	Marshal        bool
 	description    string
+	customHelpText string
 	flagKeys       InsertionOrderedMap
 	groups         []groupData
 	CommandLine    *flag.FlagSet
@@ -82,6 +83,11 @@ func (flagSet *FlagSet) SetDescription(description string) {
 	flagSet.description = description
 }
 
+// SetCustomHelpText sets the help text for a flagSet to a value. This variable appends text to the default help text.
+func (flagSet *FlagSet) SetCustomHelpText(helpText string) {
+	flagSet.customHelpText = helpText
+}
+
 // SetGroup sets a group with name and description for the command line options
 //
 // The order in which groups are passed is also kept as is, similar to flags.
@@ -501,8 +507,7 @@ func (flagSet *FlagSet) usageFunc() {
 
 	writer := tabwriter.NewWriter(cliOutput, 0, 0, 1, ' ', 0)
 
-	// If user has specified group with help and we have groups, return
-	// with it's usage function
+	// If a user has specified a group with help, and we have groups, return with the tool's usage function
 	if len(flagSet.groups) > 0 && len(os.Args) == 3 {
 		group := flagSet.getGroupbyName(strings.ToLower(os.Args[2]))
 		if group.name != "" {
@@ -521,6 +526,11 @@ func (flagSet *FlagSet) usageFunc() {
 	} else {
 		flagSet.usageFuncInternal(writer)
 	}
+
+	// If there is a custom help text specified, print it
+	if !isEmpty(flagSet.customHelpText) {
+		fmt.Fprintf(cliOutput, "\n%s\n", flagSet.customHelpText)
+	}
 }
 
 func (flagSet *FlagSet) getGroupbyName(name string) groupData {
@@ -641,10 +651,6 @@ func (u *uniqueDeduper) isUnique(data *FlagData) bool {
 	return true
 }
 
-func isNotBlank(value string) bool {
-	return len(strings.TrimSpace(value)) != 0
-}
-
 func createUsageString(data *FlagData, currentFlag *flag.Flag) string {
 	valueType := reflect.TypeOf(currentFlag.Value)
 
@@ -703,7 +709,7 @@ func createUsageFlagNames(data *FlagData) string {
 
 	var validFlags []string
 	addValidParam := func(value string) {
-		if isNotBlank(value) {
+		if !isEmpty(value) {
 			validFlags = append(validFlags, fmt.Sprintf("-%s", value))
 		}
 	}