add shape hierarchy

d2compiler/compile_test.go

@@ -2848,6 +2848,14 @@ y.source-arrowhead.shape: cf-one
 			expErr: `d2/testdata/d2compiler/TestCompile/no_arrowheads_in_shape.d2:1:3: "target-arrowhead" can only be used on connections
 d2/testdata/d2compiler/TestCompile/no_arrowheads_in_shape.d2:2:3: "source-arrowhead" can only be used on connections`,
 		},
+		{
+			name: "shape-hierarchy",
+			text: `x: {
+  shape: hierarchy
+  a -> b
+}
+`,
+		},
 	}
 
 	for _, tc := range testCases {

d2renderers/d2svg/d2svg.go

@@ -1036,7 +1036,7 @@ func drawShape(writer, appendixWriter io.Writer, diagramHash string, targetShape
 		fmt.Fprint(writer, el.Render())
 
 	// TODO should standardize "" to rectangle
-	case d2target.ShapeRectangle, d2target.ShapeSequenceDiagram, "":
+	case d2target.ShapeRectangle, d2target.ShapeSequenceDiagram, d2target.ShapeHierarchy, "":
 		borderRadius := math.MaxFloat64
 		if targetShape.BorderRadius != 0 {
 			borderRadius = float64(targetShape.BorderRadius)

d2target/d2target.go

@@ -881,6 +881,7 @@ const (
 	ShapeSQLTable        = "sql_table"
 	ShapeImage           = "image"
 	ShapeSequenceDiagram = "sequence_diagram"
+	ShapeHierarchy       = "hierarchy"
 )
 
 var Shapes = []string{
@@ -907,6 +908,7 @@ var Shapes = []string{
 	ShapeSQLTable,
 	ShapeImage,
 	ShapeSequenceDiagram,
+	ShapeHierarchy,
 }
 
 func IsShape(s string) bool {
@@ -974,6 +976,7 @@ var DSL_SHAPE_TO_SHAPE_TYPE = map[string]string{
 	ShapeSQLTable:        shape.TABLE_TYPE,
 	ShapeImage:           shape.IMAGE_TYPE,
 	ShapeSequenceDiagram: shape.SQUARE_TYPE,
+	ShapeHierarchy:       shape.SQUARE_TYPE,
 }
 
 var SHAPE_TYPE_TO_DSL_SHAPE map[string]string