Merge pull request #32 from choria-io/31

(#31) Attempt to intelligently show global flags

app.go

@@ -42,6 +42,7 @@ type Application struct {
 	completion         bool
 	cheats             map[string]string
 	cheatTags          []string
+	helpFlagIsSet      bool
 
 	// Help flag. Exposed for user customisation.
 	HelpFlag *FlagClause
@@ -75,7 +76,7 @@ func New(name, help string) *Application {
 	a.flagGroup = newFlagGroup()
 	a.argGroup = newArgGroup()
 	a.cmdGroup = newCmdGroup(a)
-	a.HelpFlag = a.Flag("help", "Show context-sensitive help")
+	a.HelpFlag = a.Flag("help", "Show context-sensitive help").IsSetByUser(&a.helpFlagIsSet)
 	a.HelpFlag.UnNegatableBool()
 
 	a.Flag("help-long", "Generate long help.").Hidden().PreAction(a.generateLongHelp).UnNegatableBool()

templates.go

@@ -127,10 +127,13 @@ Commands:
 Flags:
 {{.Context.SelectedCommand.Flags|FlagsToTwoColumns|FormatTwoColumns}}
 {{end -}}
-{{else -}}
-{{if .Context.Flags|VisibleFlags -}}
+{{end -}}
+{{if GlobalFlags .Context|VisibleFlags -}}
+{{if .HelpFlagIsSet -}}
 Global Flags:
-{{.Context.Flags|FlagsToTwoColumns|FormatTwoColumns}}
+{{ GlobalFlags .Context|FlagsToTwoColumns|FormatTwoColumns}}
+{{else -}}
+Pass --help to see global flags applicable to this command.
 {{end -}}
 {{end -}}
 `

usage.go

@@ -51,6 +51,7 @@ func formatTwoColumns(w io.Writer, indent, padding, width int, rows [][2]string)
 func (a *Application) Usage(args []string) {
 	context, err := a.parseContext(true, args)
 	a.FatalIfError(err, "")
+
 	if err := a.UsageForContextWithTemplate(context, 2, a.usageTemplate); err != nil {
 		panic(err)
 	}
@@ -111,9 +112,10 @@ type templateParseContext struct {
 }
 
 type templateContext struct {
-	App     *ApplicationModel
-	Width   int
-	Context *templateParseContext
+	App           *ApplicationModel
+	HelpFlagIsSet bool
+	Width         int
+	Context       *templateParseContext
 }
 
 // UsageForContext displays usage information from a ParseContext (obtained from
@@ -162,6 +164,33 @@ func (a *Application) UsageForContextWithTemplate(context *ParseContext, indent
 			}
 			return rows
 		},
+		"GlobalFlags": func(c *templateParseContext) []*FlagModel {
+			if c.SelectedCommand == nil {
+				return c.Flags
+			}
+
+			var sflags []string
+			for _, f := range c.SelectedCommand.Flags {
+				sflags = append(sflags, f.Name)
+			}
+
+			var globals []*FlagModel
+			for _, f := range c.Flags {
+				var known bool
+				for _, sf := range sflags {
+					if f.Name == sf {
+						known = true
+						break
+					}
+				}
+
+				if !known {
+					globals = append(globals, f)
+				}
+			}
+
+			return globals
+		},
 		"RequiredFlags": func(f []*FlagModel) []*FlagModel {
 			requiredFlags := []*FlagModel{}
 			for _, flag := range f {
@@ -251,8 +280,9 @@ func (a *Application) UsageForContextWithTemplate(context *ParseContext, indent
 		selectedCommand = context.SelectedCommand.Model()
 	}
 	ctx := templateContext{
-		App:   a.Model(),
-		Width: width,
+		App:           a.Model(),
+		Width:         width,
+		HelpFlagIsSet: a.helpFlagIsSet,
 		Context: &templateParseContext{
 			SelectedCommand: selectedCommand,
 			FlagGroupModel:  context.flags.Model(),