Implement SetHighlightedFunc (#6)

builder/properties.go

@@ -145,6 +145,18 @@ func (pm *PropertyMapper) applyTextViewProperties(tv *tview.TextView, prim *conf
 			}
 		})
 	}
+	if prim.Regions && prim.OnHighlighted != "" && pm.executor != nil {
+		onHighlightedExpr := prim.OnHighlighted
+		tv.SetHighlightedFunc(func(added, removed, remaining []string) {
+			if len(added) == 0 {
+				return
+			}
+			pm.context.SetStateDirect("__highlightedRegion", added[0])
+			if cb, err := pm.executor.ExecuteCallback(onHighlightedExpr); err == nil {
+				cb()
+			}
+		})
+	}
 	return nil
 }
 

builder/properties_test.go

@@ -0,0 +1,74 @@
+package builder
+
+import (
+	"testing"
+
+	"github.com/cassdeckard/tviewyaml/config"
+	"github.com/cassdeckard/tviewyaml/template"
+	"github.com/rivo/tview"
+)
+
+func TestApplyTextViewProperties_OnHighlighted(t *testing.T) {
+	app := tview.NewApplication()
+	pages := tview.NewPages()
+	ctx := template.NewContext(app, pages)
+	registry := template.NewFunctionRegistry()
+	executor := template.NewExecutor(ctx, registry)
+	pm := NewPropertyMapper(ctx, executor)
+
+	tv := tview.NewTextView()
+	tv.SetRegions(true)
+	tv.SetText(`["a"]Region A[""]`)
+
+	prim := &config.Primitive{
+		Type:          "textView",
+		Regions:       true,
+		OnHighlighted: `{{ showNotification "highlighted" }}`,
+	}
+
+	err := pm.ApplyProperties(tv, prim)
+	if err != nil {
+		t.Fatalf("ApplyProperties: %v", err)
+	}
+	// Wiring succeeded; SetHighlightedFunc is attached. The callback runs when
+	// tview draws after a highlight change (tested via acceptance if needed).
+}
+
+func TestBuildFlex_TextViewWithOnHighlighted(t *testing.T) {
+	app := tview.NewApplication()
+	pages := tview.NewPages()
+	ctx := template.NewContext(app, pages)
+	registry := template.NewFunctionRegistry()
+	b := NewBuilder(ctx, registry)
+
+	pageConfig := &config.PageConfig{
+		Type: "flex",
+		Items: []config.FlexItem{
+			{
+				Primitive: &config.Primitive{
+					Type:          "textView",
+					Regions:       true,
+					DynamicColors: true,
+					Text:          `["slide1"]Slide 1[""] ["slide2"]Slide 2[""]`,
+					OnHighlighted: `{{ switchToPage "main" }}`,
+				},
+				FixedSize:  0,
+				Proportion: 1,
+				Focus:     true,
+			},
+		},
+	}
+
+	result, err := b.BuildFromConfig(pageConfig)
+	if err != nil {
+		t.Fatalf("BuildFromConfig: %v", err)
+	}
+
+	flex, ok := result.(*tview.Flex)
+	if !ok {
+		t.Fatalf("expected *tview.Flex, got %T", result)
+	}
+	if flex.GetItemCount() != 1 {
+		t.Errorf("GetItemCount() = %d, want 1", flex.GetItemCount())
+	}
+}

config/types.go

@@ -95,6 +95,8 @@ type Primitive struct {
 	OnCancel      string     `yaml:"onCancel,omitempty"` // Template expression when form is cancelled (Escape); if unset and OnSubmit set, Escape runs OnSubmit
 	// onDone: Template expression when user presses Enter/Escape (TextView, InputField, Table)
 	OnDone string `yaml:"onDone,omitempty"`
+	// onHighlighted: Template expression when highlighted region changes (TextView with regions; state: __highlightedRegion)
+	OnHighlighted string `yaml:"onHighlighted,omitempty"`
 	// Table-specific properties
 	OnCellSelected string   `yaml:"onCellSelected,omitempty"` // Template expression when a cell is selected (state: __selectedCellText, __selectedRow, __selectedCol)
 	Borders        bool     `yaml:"borders,omitempty"`        // Show borders between cells

docs/tview-coverage.md

@@ -19,7 +19,7 @@ This table maps [tview](https://pkg.go.dev/github.com/rivo/tview) primitives and
 | **Pages** | Yes | Yes (root) | Yes | [app.yaml](../example/config/app.yaml), [nested-pages.yaml](../example/config/nested-pages.yaml) | Tab-like page switching; `ref` to YAML files |
 | **Table** | Yes | Yes | Yes | [table.yaml](../example/config/table.yaml) | Headers, rows, borders, fixed rows/columns; `onDone` for Enter/Escape |
 | **TextArea** | Yes | No | Yes (Form item) | [form.yaml](../example/config/form.yaml) | Form item type `textarea`; multi-line input |
-| **TextView** | Yes | No | Yes | [textview.yaml](../example/config/textview.yaml) | Dynamic colors, regions, scrollable; `onDone` for Enter/Escape |
+| **TextView** | Yes | No | Yes | [textview.yaml](../example/config/textview.yaml) | Dynamic colors, regions, scrollable; `onDone` for Enter/Escape; `onHighlighted` for region clicks |
 | **TreeView** | Yes | Yes | Yes | [treeview.yaml](../example/config/treeview.yaml), [treeview-standalone.yaml](../example/config/treeview-standalone.yaml), [treeview-modes.yaml](../example/config/treeview-modes.yaml) | Nodes with children; selectable modes |
 
 ## Form Item Types
@@ -48,6 +48,10 @@ TextView, InputField (standalone), and Table support `onDone`—a template expre
 
 Note: tview's Table does not call SetDoneFunc for Enter when rows are selectable—Enter is used for selection. Escape still triggers onDone on selectable tables.
 
+## Callback Support: onHighlighted (TextView)
+
+TextView with `regions: true` supports `onHighlighted`—a template expression that runs when the highlighted region changes (from clicks or Tab/Enter navigation). State `__highlightedRegion` is set to the first newly highlighted region ID before the callback runs. Use `switchToPage "{{ bindState __highlightedRegion }}"` for presentation-style info bar navigation. See [textview.yaml](../example/config/textview.yaml).
+
 ## Additional Example Configs (Feature Demos)
 
 | Config | Purpose |

example/acceptance/testdata/snapshots/120x30/TestAcceptance/KeyNavigation_TextViewPage.terminal

@@ -23,8 +23,8 @@
 ║                                                                                                                      ║
 ║                                                                                                                      ║
 ║                                                                                                                      ║
-║                                                                                                                      ║
-║                                                                                                                      ║
 ╚══════════════════════════════════════════════════════════════════════════════════════════════════════════════════════╝
              Enter to start selection, Tab/Backtab to navigate regions, arrow keys to scroll, ESC to return             
+                                                                                                                        
+                                                        Status:                                                         
                                                                                                                         

example/acceptance/testdata/snapshots/40x10/TestAcceptance/KeyNavigation_TextViewPage.terminal

@@ -3,8 +3,8 @@
    Text display with dynamic colors,    
    regions, highlights, and scrolling   
 ╔═══TextView with Colors and Regions═══╗
-║TextView Features:                    ║
-║                                      ║
 ╚══════════════════════════════════════╝
  Enter to start selection, Tab/Backtab  
-  to navigate regions, arrow keys to    
+  to navigate regions, arrow keys to    
+         scroll, ESC to return          
+                                        

example/acceptance/testdata/snapshots/80x24/TestAcceptance/KeyNavigation_TextViewPage.terminal

@@ -17,8 +17,8 @@
 ║                                                                              ║
 ║4. Word Wrap: Long lines automatically wrap to fit the view                   ║
 ║                                                                              ║
-║Press Enter to start region selection, Tab/Backtab to navigate regions        ║
-║                                                                              ║
 ╚══════════════════════════════════════════════════════════════════════════════╝
    Enter to start selection, Tab/Backtab to navigate regions, arrow keys to     
-                             scroll, ESC to return                              
+                             scroll, ESC to return                              
+                                                                                
+                                    Status:                                     

example/config/textview.yaml

@@ -18,6 +18,7 @@ items:
       title: "TextView with Colors and Regions"
       dynamicColors: true
       regions: true
+      onHighlighted: '{{ showHighlightedNotification }}'
       text: |
         [yellow]TextView Features:[white]
 
@@ -40,7 +41,11 @@ items:
       type: textView
       textAlign: center
       textColor: gray
-      text: "Enter to start selection, Tab/Backtab to navigate regions, arrow keys to scroll, ESC to return"
-    fixedSize: 2
+      dynamicColors: true
+      text: |
+        Enter to start selection, Tab/Backtab to navigate regions, arrow keys to scroll, ESC to return
+
+        [green]Status:[white] {{ bindState notification }}
+    fixedSize: 4
     proportion: 1
     focus: false

template/builtins.go

@@ -28,6 +28,17 @@ func registerBuiltinFunctions(registry *FunctionRegistry) {
 		ctx.SetStateDirect("notification", msg)
 	})
 
+	// showHighlightedNotification: sets notification to "Region X selected" using __highlightedRegion.
+	// For use in onHighlighted callbacks to show which region was selected.
+	registry.Register("showHighlightedNotification", 0, intPtr(0), nil, func(ctx *Context) {
+		region, ok := ctx.GetState("__highlightedRegion")
+		msg := "Region selected"
+		if ok && fmt.Sprint(region) != "" {
+			msg = fmt.Sprintf("Region %s selected", region)
+		}
+		ctx.SetStateDirect("notification", msg)
+	})
+
 	// switchToPage: switches to a different page
 	registry.Register("switchToPage", 1, intPtr(1), nil, func(ctx *Context, pageName string) {
 		if ctx.Pages != nil {