From b900f6341487996174ec75905d3670c48ba4f7fe Mon Sep 17 00:00:00 2001
From: Anmol Sethi <anmol@terrastruct.com>
Date: Sun, 22 Jan 2023 01:08:13 -0800
Subject: [PATCH] d2compiler: Integrate d2ir (wip)

---
 d2compiler/compile.go |  6 ++++++
 d2ir/d2ir.go          | 25 ++++++++++++++++++-------
 2 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/d2compiler/compile.go b/d2compiler/compile.go
index 3133456dd..9f4512dd5 100644
--- a/d2compiler/compile.go
+++ b/d2compiler/compile.go
@@ -168,6 +168,9 @@ func (c *compiler) compileLabel(attrs *d2graph.Attributes, f d2ir.Node) {
 }
 
 func (c *compiler) compileReserved(attrs *d2graph.Attributes, f *d2ir.Field) {
+	if f.Primary() == nil {
+		return
+	}
 	scalar := f.Primary().Value
 	switch f.Name {
 	case "label":
@@ -240,6 +243,9 @@ func (c *compiler) compileStyle(attrs *d2graph.Attributes, m *d2ir.Map) {
 }
 
 func (c *compiler) compileStyleField(attrs *d2graph.Attributes, f *d2ir.Field) {
+	if f.Primary() == nil {
+		return
+	}
 	scalar := f.Primary().Value
 	err := attrs.Style.Apply(f.Name, scalar.ScalarString())
 	if err != nil {
diff --git a/d2ir/d2ir.go b/d2ir/d2ir.go
index 438eaf1c9..15788ee3d 100644
--- a/d2ir/d2ir.go
+++ b/d2ir/d2ir.go
@@ -235,7 +235,8 @@ func NodeLayerKind(n Node) LayerKind {
 }
 
 type Field struct {
-	parent *Map
+	// *Map.
+	parent Node
 
 	Name string `json:"name"`
 
@@ -249,7 +250,7 @@ func (f *Field) Copy(newParent Node) Node {
 	tmp := *f
 	f = &tmp
 
-	f.parent = newParent.(*Map)
+	f.parent = newParent
 	f.References = append([]*FieldReference(nil), f.References...)
 	if f.Primary_ != nil {
 		f.Primary_ = f.Primary_.Copy(f).(*Scalar)
@@ -397,7 +398,8 @@ func (eid *EdgeID) trimCommon() (common []string, _ *EdgeID) {
 }
 
 type Edge struct {
-	parent *Map
+	// *Map
+	parent Node
 
 	ID *EdgeID `json:"edge_id"`
 
@@ -411,7 +413,7 @@ func (e *Edge) Copy(newParent Node) Node {
 	tmp := *e
 	e = &tmp
 
-	e.parent = newParent.(*Map)
+	e.parent = newParent
 	e.References = append([]*EdgeReference(nil), e.References...)
 	if e.Primary_ != nil {
 		e.Primary_ = e.Primary_.Copy(e).(*Scalar)
@@ -898,8 +900,11 @@ func (m *Map) appendFieldReferences(i int, kp *d2ast.KeyPath, refctx *RefContext
 }
 
 func ParentMap(n Node) *Map {
-	for n.Parent() != nil {
+	for {
 		n = n.Parent()
+		if n == nil {
+			return nil
+		}
 		if m, ok := n.(*Map); ok {
 			return m
 		}
@@ -908,8 +913,11 @@ func ParentMap(n Node) *Map {
 }
 
 func ParentField(n Node) *Field {
-	for n.Parent() != nil {
+	for {
 		n = n.Parent()
+		if n == nil {
+			return nil
+		}
 		if f, ok := n.(*Field); ok {
 			return f
 		}
@@ -932,8 +940,11 @@ func ParentLayer(n Node) *Map {
 }
 
 func ParentEdge(n Node) *Edge {
-	for n.Parent() != nil {
+	for {
 		n = n.Parent()
+		if n == nil {
+			return nil
+		}
 		if e, ok := n.(*Edge); ok {
 			return e
 		}