feat: expand parent colors

src/writer_ansi.go

@@ -24,7 +24,7 @@ type AnsiWriter struct {
 	ansi               *ansiUtils
 	terminalBackground string
 	Colors             *Color
-	ParentColors       *Color
+	ParentColors       []*Color
 	ansiColors         AnsiColors
 }
 
@@ -80,10 +80,13 @@ func (a *AnsiWriter) setColors(background, foreground string) {
 }
 
 func (a *AnsiWriter) setParentColors(background, foreground string) {
-	a.ParentColors = &Color{
+	if a.ParentColors == nil {
+		a.ParentColors = make([]*Color, 0)
+	}
+	a.ParentColors = append([]*Color{{
 		Background: background,
 		Foreground: foreground,
-	}
+	}}, a.ParentColors...)
 }
 
 func (a *AnsiWriter) clearParentColors() {
@@ -183,16 +186,30 @@ func (a *AnsiWriter) isKeyword(color string) bool {
 }
 
 func (a *AnsiWriter) expandKeyword(keyword string) string {
+	resolveParentColor := func(keyword string) string {
+		for _, color := range a.ParentColors {
+			if color == nil {
+				return Transparent
+			}
+			switch keyword {
+			case ParentBackground:
+				keyword = color.Background
+			case ParentForeground:
+				keyword = color.Foreground
+			default:
+				return keyword
+			}
+		}
+		return keyword
+	}
 	resolveKeyword := func(keyword string) string {
 		switch {
 		case keyword == Background && a.Colors != nil:
 			return a.Colors.Background
 		case keyword == Foreground && a.Colors != nil:
 			return a.Colors.Foreground
-		case keyword == ParentBackground && a.ParentColors != nil:
-			return a.ParentColors.Background
-		case keyword == ParentForeground && a.ParentColors != nil:
-			return a.ParentColors.Foreground
+		case (keyword == ParentBackground || keyword == ParentForeground) && a.ParentColors != nil:
+			return resolveParentColor(keyword)
 		default:
 			return Transparent
 		}

src/writer_ansi_test.go

@@ -175,7 +175,7 @@ func TestWriteANSIColors(t *testing.T) {
 		ansi.init("pwsh")
 		renderer := &AnsiWriter{
 			ansi:               ansi,
-			ParentColors:       tc.Parent,
+			ParentColors:       []*Color{tc.Parent},
 			Colors:             tc.Colors,
 			terminalBackground: tc.TerminalBackground,
 			ansiColors:         &DefaultColors{},