Add support for dynamic binding descriptions

Author: stefanhaller

pkg/gui/controllers/options_menu_action.go

@@ -25,7 +25,7 @@ func (self *OptionsMenuAction) Call() error {
 				}
 				return &types.MenuItem{
 					OpensMenu: binding.OpensMenu,
-					Label:     binding.Description,
+					Label:     binding.GetDescription(),
 					OnPress: func() error {
 						if binding.Handler == nil {
 							return nil
@@ -60,7 +60,7 @@ func (self *OptionsMenuAction) getBindings(context types.Context) ([]*types.Bind
 	bindings, _ := self.c.GetInitialKeybindingsWithCustomCommands()
 
 	for _, binding := range bindings {
-		if binding.Description != "" {
+		if binding.GetDescription() != "" {
 			if binding.ViewName == "" || binding.Tag == "global" {
 				bindingsGlobal = append(bindingsGlobal, binding)
 			} else if binding.ViewName == context.GetViewName() {
@@ -80,6 +80,6 @@ func (self *OptionsMenuAction) getBindings(context types.Context) ([]*types.Bind
 // handler in the keybinding struct.
 func uniqueBindings(bindings []*types.Binding) []*types.Binding {
 	return lo.UniqBy(bindings, func(binding *types.Binding) string {
-		return binding.Description
+		return binding.GetDescription()
 	})
 }

pkg/gui/types/keybindings.go

@@ -16,12 +16,20 @@ type Binding struct {
 	Key         Key
 	Modifier    gocui.Modifier
 	Description string
+	// DescriptionFunc is used instead of Description if non-nil, and is useful for dynamic
+	// descriptions that change depending on context. Important: this must not be an expensive call.
+	// Note that you should still provide a generic, non-dynamic description in the Description field,
+	// as this is used in the cheatsheet.
+	DescriptionFunc func() string
 	// If defined, this is used in place of Description when showing the keybinding
 	// in the options view at the bottom left of the screen.
 	ShortDescription string
-	Alternative      string
-	Tag              string // e.g. 'navigation'. Used for grouping things in the cheatsheet
-	OpensMenu        bool
+	// ShortDescriptionFunc is used instead of ShortDescription if non-nil, and is useful for dynamic
+	// descriptions that change depending on context. Important: this must not be an expensive call.
+	ShortDescriptionFunc func() string
+	Alternative          string
+	Tag                  string // e.g. 'navigation'. Used for grouping things in the cheatsheet
+	OpensMenu            bool
 
 	// If true, the keybinding will appear at the bottom of the screen.
 	// Even if set to true, the keybinding will not be displayed if it is currently
@@ -47,11 +55,21 @@ func (b *Binding) IsDisabled() bool {
 	return b.GetDisabledReason != nil && b.GetDisabledReason() != nil
 }
 
+func (b *Binding) GetDescription() string {
+	if b.DescriptionFunc != nil {
+		return b.DescriptionFunc()
+	}
+	return b.Description
+}
+
 func (b *Binding) GetShortDescription() string {
+	if b.ShortDescriptionFunc != nil {
+		return b.ShortDescriptionFunc()
+	}
 	if b.ShortDescription != "" {
 		return b.ShortDescription
 	}
-	return b.Description
+	return b.GetDescription()
 }
 
 // A guard is a decorator which checks something before executing a handler