diff --git a/d2ir/apply.go b/d2ir/apply.go
deleted file mode 100644
index 462c2cc88..000000000
--- a/d2ir/apply.go
+++ /dev/null
@@ -1,83 +0,0 @@
-package d2ir
-
-import (
-	"fmt"
-
-	"oss.terrastruct.com/d2/d2ast"
-	"oss.terrastruct.com/d2/d2format"
-	"oss.terrastruct.com/d2/d2parser"
-)
-
-type compiler struct {
-	err d2parser.ParseError
-}
-
-func (c *compiler) errorf(n d2ast.Node, f string, v ...interface{}) {
-	f = "%v: " + f
-	v = append([]interface{}{n.GetRange()}, v...)
-	c.err.Errors = append(c.err.Errors, d2ast.Error{
-		Range:   n.GetRange(),
-		Message: fmt.Sprintf(f, v...),
-	})
-}
-
-func Apply(dst *Map, ast *d2ast.Map) error {
-	var c compiler
-	c.compileMap(dst, ast)
-	if !c.err.Empty() {
-		return c.err
-	}
-	return nil
-}
-
-func (c *compiler) compileMap(dst *Map, ast *d2ast.Map) {
-	for _, n := range ast.Nodes {
-		switch {
-		case n.MapKey != nil:
-			c.compileField(dst, n.MapKey)
-		case n.Substitution != nil:
-			panic("TODO")
-		}
-	}
-}
-
-func (c *compiler) compileField(dst *Map, k *d2ast.Key) {
-	if k.Key != nil && len(k.Key.Path) > 0 {
-		f, ok := dst.Ensure(d2format.KeyPath(k.Key))
-		if !ok {
-			c.errorf(k, "cannot index into array")
-			return
-		}
-
-		if len(k.Edges) == 0 {
-			if k.Primary.Unbox() != nil {
-				f.Primary = &Scalar{
-					parent: f,
-					Value:  k.Primary.Unbox(),
-				}
-			}
-			if k.Value.Array != nil {
-				a := &Array{
-					parent: f,
-				}
-				c.compileArray(a, k.Value.Array)
-				f.Composite = a
-			} else if k.Value.Map != nil {
-				m := &Map{
-					parent: f,
-				}
-				c.compileMap(m, k.Value.Map)
-				f.Composite = m
-			} else if k.Value.ScalarBox().Unbox() != nil {
-				f.Primary = &Scalar{
-					parent: f,
-					Value:  k.Value.ScalarBox().Unbox(),
-				}
-			}
-		}
-	}
-}
-
-func (c *compiler) compileArray(dst *Array, a *d2ast.Array) {
-	panic(fmt.Sprintf("TODO"))
-}
diff --git a/d2ir/compile.go b/d2ir/compile.go
new file mode 100644
index 000000000..0f9587eed
--- /dev/null
+++ b/d2ir/compile.go
@@ -0,0 +1,171 @@
+package d2ir
+
+import (
+	"fmt"
+
+	"oss.terrastruct.com/d2/d2ast"
+	"oss.terrastruct.com/d2/d2format"
+	"oss.terrastruct.com/d2/d2parser"
+)
+
+type compiler struct {
+	err d2parser.ParseError
+}
+
+func (c *compiler) errorf(n d2ast.Node, f string, v ...interface{}) {
+	f = "%v: " + f
+	v = append([]interface{}{n.GetRange()}, v...)
+	c.err.Errors = append(c.err.Errors, d2ast.Error{
+		Range:   n.GetRange(),
+		Message: fmt.Sprintf(f, v...),
+	})
+}
+
+func Compile(dst *Map, ast *d2ast.Map) error {
+	var c compiler
+	c.compileMap(dst, ast)
+	if !c.err.Empty() {
+		return c.err
+	}
+	return nil
+}
+
+func (c *compiler) compileMap(dst *Map, ast *d2ast.Map) {
+	for _, n := range ast.Nodes {
+		switch {
+		case n.MapKey != nil:
+			c.compileKey(dst, n.MapKey)
+		case n.Substitution != nil:
+			panic("TODO")
+		}
+	}
+}
+
+func (c *compiler) compileKey(dst *Map, k *d2ast.Key) {
+	if len(k.Edges) == 0 {
+		c.compileField(dst, k)
+	} else {
+		c.compileEdges(dst, k)
+	}
+}
+
+func (c *compiler) compileField(dst *Map, k *d2ast.Key) {
+	f, err := dst.Ensure(d2format.KeyPath(k.Key))
+	if err != nil {
+		c.errorf(k, err.Error())
+		return
+	}
+
+	if k.Primary.Unbox() != nil {
+		f.Primary = &Scalar{
+			parent: f,
+			Value:  k.Primary.Unbox(),
+		}
+	}
+	if k.Value.Array != nil {
+		a := &Array{
+			parent: f,
+		}
+		c.compileArray(a, k.Value.Array)
+		f.Composite = a
+	} else if k.Value.Map != nil {
+		if f_m, ok := f.Composite.(*Map); ok {
+			c.compileMap(f_m, k.Value.Map)
+		} else {
+			m := &Map{
+				parent: f,
+			}
+			c.compileMap(m, k.Value.Map)
+			f.Composite = m
+		}
+	} else if k.Value.ScalarBox().Unbox() != nil {
+		f.Primary = &Scalar{
+			parent: f,
+			Value:  k.Value.ScalarBox().Unbox(),
+		}
+	}
+}
+
+func (c *compiler) compileEdges(dst *Map, k *d2ast.Key) {
+	if k.Key != nil && len(k.Key.Path) > 0 {
+		f, err := dst.Ensure(d2format.KeyPath(k.Key))
+		if err != nil {
+			c.errorf(k, err.Error())
+			return
+		}
+		if f_m, ok := f.Composite.(*Map); ok {
+			dst = f_m
+		} else {
+			m := &Map{
+				parent: f,
+			}
+			f.Composite = m
+			dst = m
+		}
+	}
+
+	eida := NewEdgeIDs(k)
+	for i, eid := range eida {
+		var e *Edge
+		if eid.Index != nil {
+			ea := dst.GetEdges(eid)
+			if len(ea) == 0 {
+				c.errorf(k.Edges[i], "indexed edge does not exist")
+				continue
+			}
+			e = ea[0]
+		} else {
+			var err error
+			e, err = dst.EnsureEdge(eid)
+			if err != nil {
+				c.errorf(k.Edges[i], err.Error())
+				continue
+			}
+		}
+
+		_, err := dst.Ensure(eid.SrcPath)
+		if err != nil {
+			c.errorf(k.Edges[i].Src, err.Error())
+			continue
+		}
+		_, err = dst.Ensure(eid.DstPath)
+		if err != nil {
+			c.errorf(k.Edges[i].Dst, err.Error())
+			continue
+		}
+
+		if k.EdgeKey != nil {
+			if e.Map == nil {
+				e.Map = &Map{
+					parent: e,
+				}
+			}
+			tmpk := &d2ast.Key{
+				Range: k.EdgeKey.Range,
+				Key:   k.EdgeKey,
+			}
+			c.compileField(e.Map, tmpk)
+		} else {
+			if k.Primary.Unbox() != nil {
+				e.Primary = &Scalar{
+					parent: e,
+					Value:  k.Primary.Unbox(),
+				}
+			} else if k.Value.Map != nil {
+				if e.Map == nil {
+					e.Map = &Map{
+						parent: e,
+					}
+				}
+				c.compileMap(e.Map, k.Value.Map)
+			} else if k.Value.Unbox() != nil {
+				c.errorf(k.Value.Unbox(), "edges cannot be assigned arrays")
+				continue
+			}
+		}
+	}
+}
+
+func (c *compiler) compileArray(dst *Array, a *d2ast.Array) {
+	panic(fmt.Sprintf("TODO"))
+}
diff --git a/d2ir/apply_test.go b/d2ir/compile_test.go
similarity index 86%
rename from d2ir/apply_test.go
rename to d2ir/compile_test.go
index 9e53f0a40..7cb3d1df4 100644
--- a/d2ir/apply_test.go
+++ b/d2ir/compile_test.go
@@ -11,7 +11,6 @@ import (
 	"oss.terrastruct.com/util-go/diff"
 
 	"oss.terrastruct.com/d2/d2ast"
-	"oss.terrastruct.com/d2/d2format"
 	"oss.terrastruct.com/d2/d2ir"
 	"oss.terrastruct.com/d2/d2parser"
 )
@@ -21,13 +20,13 @@ type testCase struct {
 	run  func(testing.TB, *d2ir.Map)
 }
 
-func TestApply(t *testing.T) {
+func TestCompile(t *testing.T) {
 	t.Parallel()
 
-	t.Run("simple", testApplySimple)
+	t.Run("roots", testCompileRoots)
 }
 
-func testApplySimple(t *testing.T) {
+func testCompileRoots(t *testing.T) {
 	t.Parallel()
 
 	tca := []testCase{
@@ -118,7 +117,7 @@ func testApplySimple(t *testing.T) {
 			run: func(t testing.TB, m *d2ir.Map) {
 				err := parse(t, m, `x._ -> z`)
 				assert.Success(t, err)
-				assertField(t, m, 2, 1, nil)
+				assertField(t, m, 3, 1, nil)
 
 				assertField(t, m, 0, 0, nil, "x")
 				assertField(t, m, 0, 0, nil, "z")
@@ -149,7 +148,7 @@ func parse(t testing.TB, dst *d2ir.Map, text string) error {
 	ast, err := d2parser.Parse(d2Path, strings.NewReader(text), nil)
 	assert.Success(t, err)
 
-	err = d2ir.Apply(dst, ast)
+	err = d2ir.Compile(dst, ast)
 	if err != nil {
 		return err
 	}
@@ -182,10 +181,9 @@ func assertField(t testing.TB, n d2ir.Node, nfields, nedges int, primary interfa
 	}
 
 	var f *d2ir.Field
-	var ok bool
 	if len(ida) > 0 {
-		f, ok = m.Get(ida)
-		if !ok {
+		f = m.Get(ida)
+		if f == nil {
 			t.Fatalf("expected field %v in map %s", ida, m)
 		}
 		p = f.Primary
@@ -196,8 +194,8 @@ func assertField(t testing.TB, n d2ir.Node, nfields, nedges int, primary interfa
 		}
 	}
 
-	assert.Equal(t, nfields, m.FieldCount())
-	assert.Equal(t, nedges, m.EdgeCount())
+	assert.Equal(t, nfields, m.FieldCountRecursive())
+	assert.Equal(t, nedges, m.EdgeCountRecursive())
 	if !makeScalar(p).Equal(makeScalar(primary)) {
 		t.Fatalf("expected primary %#v but got %s", primary, p)
 	}
@@ -205,24 +203,13 @@ func assertField(t testing.TB, n d2ir.Node, nfields, nedges int, primary interfa
 	return f
 }
 
-func parseEdgeID(t testing.TB, eids string) *d2ir.EdgeID {
-	t.Helper()
-	k, err := d2parser.ParseMapKey(eids)
-	assert.Success(t, err)
-
-	return &d2ir.EdgeID{
-		SrcPath:  d2format.KeyPath(k.Edges[0].Src),
-		SrcArrow: k.Edges[0].SrcArrow == "<",
-		DstPath:  d2format.KeyPath(k.Edges[0].Dst),
-		DstArrow: k.Edges[0].DstArrow == ">",
-		Index:    *k.EdgeIndex.Int,
-	}
-}
-
 func assertEdge(t testing.TB, n d2ir.Node, nfields int, primary interface{}, eids string) *d2ir.Edge {
 	t.Helper()
 
-	eid := parseEdgeID(t, eids)
+	k, err := d2parser.ParseMapKey(eids)
+	assert.Success(t, err)
+
+	eid := d2ir.NewEdgeIDs(k)[0]
 
 	var m *d2ir.Map
 	switch n := n.(type) {
@@ -239,12 +226,13 @@ func assertEdge(t testing.TB, n d2ir.Node, nfields int, primary interface{}, eid
 		t.Fatalf("unexpected d2ir.Node %T", n)
 	}
 
-	e, ok := m.GetEdge(eid)
-	if !ok {
-		t.Fatalf("expected edge %v in map %s but not found", eid, m)
+	ea := m.GetEdges(eid)
+	if len(ea) != 1 {
+		t.Fatalf("expected single edge %v in map %s but not found", eid, m)
 	}
+	e := ea[0]
 
-	assert.Equal(t, nfields, e.Map.FieldCount())
+	assert.Equal(t, nfields, e.Map.FieldCountRecursive())
 	if !makeScalar(e.Primary).Equal(makeScalar(primary)) {
 		t.Fatalf("expected primary %#v but %s", primary, e.Primary)
 	}
diff --git a/d2ir/d2ir.go b/d2ir/d2ir.go
index c44c3430a..3bb9154fd 100644
--- a/d2ir/d2ir.go
+++ b/d2ir/d2ir.go
@@ -2,6 +2,7 @@ package d2ir
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"strings"
 
@@ -155,7 +156,8 @@ type EdgeID struct {
 	DstPath  []string `json:"dst_path"`
 	DstArrow bool     `json:"dst_arrow"`
 
-	Index int `json:"index"`
+	// If nil, then any EdgeID with equal src/dst/arrows matches.
+	Index *int `json:"index"`
 }
 
 func (eid *EdgeID) Copy() *EdgeID {
@@ -167,9 +169,11 @@ func (eid *EdgeID) Copy() *EdgeID {
 	return eid
 }
 
-func (eid *EdgeID) Equal(eid2 *EdgeID) bool {
-	if eid.Index != eid2.Index {
-		return false
+func (eid *EdgeID) Match(eid2 *EdgeID) bool {
+	if eid.Index != nil && eid2.Index != nil {
+		if *eid.Index != *eid2.Index {
+			return false
+		}
 	}
 
 	if len(eid.SrcPath) != len(eid2.SrcPath) {
@@ -272,29 +276,40 @@ type RefContext struct {
 	Scope *d2ast.Map  `json:"-"`
 }
 
-func (m *Map) FieldCount() int {
+func (m *Map) FieldCountRecursive() int {
+	if m == nil {
+		return 0
+	}
 	acc := len(m.Fields)
 	for _, f := range m.Fields {
 		if f_m, ok := f.Composite.(*Map); ok {
-			acc += f_m.FieldCount()
+			acc += f_m.FieldCountRecursive()
+		}
+	}
+	for _, e := range m.Edges {
+		if e.Map != nil {
+			acc += e.Map.FieldCountRecursive()
 		}
 	}
 	return acc
 }
 
-func (m *Map) EdgeCount() int {
+func (m *Map) EdgeCountRecursive() int {
+	if m == nil {
+		return 0
+	}
 	acc := len(m.Edges)
 	for _, e := range m.Edges {
 		if e.Map != nil {
-			acc += e.Map.EdgeCount()
+			acc += e.Map.EdgeCountRecursive()
 		}
 	}
 	return acc
 }
 
-func (m *Map) Get(ida []string) (*Field, bool) {
+func (m *Map) Get(ida []string) *Field {
 	if len(ida) == 0 {
-		return nil, false
+		return nil
 	}
 
 	s := ida[0]
@@ -305,18 +320,18 @@ func (m *Map) Get(ida []string) (*Field, bool) {
 			continue
 		}
 		if len(rest) == 0 {
-			return f, true
+			return f
 		}
 		if f_m, ok := f.Composite.(*Map); ok {
 			return f_m.Get(rest)
 		}
 	}
-	return nil, false
+	return nil
 }
 
-func (m *Map) Ensure(ida []string) (*Field, bool) {
+func (m *Map) Ensure(ida []string) (*Field, error) {
 	if len(ida) == 0 {
-		return nil, false
+		return nil, errors.New("empty ida")
 	}
 
 	s := ida[0]
@@ -327,13 +342,13 @@ func (m *Map) Ensure(ida []string) (*Field, bool) {
 			continue
 		}
 		if len(rest) == 0 {
-			return f, true
+			return f, nil
 		}
 		switch fc := f.Composite.(type) {
 		case *Map:
 			return fc.Ensure(rest)
 		case *Array:
-			return nil, false
+			return nil, errors.New("cannot index into array")
 		}
 		f.Composite = &Map{
 			parent: f,
@@ -347,7 +362,7 @@ func (m *Map) Ensure(ida []string) (*Field, bool) {
 	}
 	m.Fields = append(m.Fields, f)
 	if len(rest) == 0 {
-		return f, true
+		return f, nil
 	}
 	f.Composite = &Map{
 		parent: f,
@@ -378,25 +393,58 @@ func (m *Map) Delete(ida []string) bool {
 	return false
 }
 
-func (m *Map) GetEdge(eid *EdgeID) (*Edge, bool) {
+func (m *Map) GetEdges(eid *EdgeID) []*Edge {
 	common, eid := eid.trimCommon()
 	if len(common) > 0 {
-		f, ok := m.Get(common)
-		if !ok {
-			return nil, false
+		f := m.Get(common)
+		if f == nil {
+			return nil
 		}
 		if f_m, ok := f.Composite.(*Map); ok {
-			return f_m.GetEdge(eid)
+			return f_m.GetEdges(eid)
 		}
-		return nil, false
+		return nil
 	}
 
+	var ea []*Edge
 	for _, e := range m.Edges {
-		if e.ID.Equal(eid) {
-			return e, true
+		if e.ID.Match(eid) {
+			ea = append(ea, e)
 		}
 	}
-	return nil, false
+	return ea
+}
+
+func (m *Map) EnsureEdge(eid *EdgeID) (*Edge, error) {
+	common, eid := eid.trimCommon()
+	if len(common) > 0 {
+		f, err := m.Ensure(common)
+		if err != nil {
+			return nil, err
+		}
+		switch fc := f.Composite.(type) {
+		case *Map:
+			return fc.EnsureEdge(eid)
+		case *Array:
+			return nil, errors.New("cannot index into array")
+		}
+		f.Composite = &Map{
+			parent: f,
+		}
+		return f.Composite.(*Map).EnsureEdge(eid)
+	}
+
+	eid.Index = nil
+	ea := m.GetEdges(eid)
+	index := len(ea)
+	eid.Index = &index
+	e := &Edge{
+		parent: m,
+		ID:     eid,
+	}
+	m.Edges = append(m.Edges, e)
+
+	return e, nil
 }
 
 func (m *Map) String() string {
@@ -406,3 +454,18 @@ func (m *Map) String() string {
 	}
 	return string(b)
 }
+
+func NewEdgeIDs(k *d2ast.Key) (eida []*EdgeID) {
+	for _, ke := range k.Edges {
+		eida = append(eida, &EdgeID{
+			SrcPath:  d2format.KeyPath(ke.Src),
+			SrcArrow: ke.SrcArrow == "<",
+			DstPath:  d2format.KeyPath(ke.Dst),
+			DstArrow: ke.DstArrow == ">",
+		})
+	}
+	if k.EdgeIndex != nil && k.EdgeIndex.Int != nil {
+		eida[0].Index = k.EdgeIndex.Int
+	}
+	return eida
+}
diff --git a/testdata/d2ir/TestCompile/roots/edge.exp.json b/testdata/d2ir/TestCompile/roots/edge.exp.json
new file mode 100644
index 000000000..67dbe62d8
--- /dev/null
+++ b/testdata/d2ir/TestCompile/roots/edge.exp.json
@@ -0,0 +1,25 @@
+{
+  "fields": [
+    {
+      "name": "x"
+    },
+    {
+      "name": "y"
+    }
+  ],
+  "edges": [
+    {
+      "edge_id": {
+        "src_path": [
+          "x"
+        ],
+        "src_arrow": false,
+        "dst_path": [
+          "y"
+        ],
+        "dst_arrow": true,
+        "index": 0
+      }
+    }
+  ]
+}
diff --git a/testdata/d2ir/TestCompile/roots/field.exp.json b/testdata/d2ir/TestCompile/roots/field.exp.json
new file mode 100644
index 000000000..2dcf9ab44
--- /dev/null
+++ b/testdata/d2ir/TestCompile/roots/field.exp.json
@@ -0,0 +1,8 @@
+{
+  "fields": [
+    {
+      "name": "x"
+    }
+  ],
+  "edges": null
+}
diff --git a/testdata/d2ir/TestCompile/roots/field/label.exp.json b/testdata/d2ir/TestCompile/roots/field/label.exp.json
new file mode 100644
index 000000000..723e59be4
--- /dev/null
+++ b/testdata/d2ir/TestCompile/roots/field/label.exp.json
@@ -0,0 +1,19 @@
+{
+  "fields": [
+    {
+      "name": "x",
+      "primary": {
+        "value": {
+          "range": "d2/testdata/d2ir/TestCompile/roots/field/label.d2,0:3:3-0:6:6",
+          "value": [
+            {
+              "string": "yes",
+              "raw_string": "yes"
+            }
+          ]
+        }
+      }
+    }
+  ],
+  "edges": null
+}
diff --git a/testdata/d2ir/TestCompile/roots/field/label/nested.exp.json b/testdata/d2ir/TestCompile/roots/field/label/nested.exp.json
new file mode 100644
index 000000000..ce902b9a6
--- /dev/null
+++ b/testdata/d2ir/TestCompile/roots/field/label/nested.exp.json
@@ -0,0 +1,27 @@
+{
+  "fields": [
+    {
+      "name": "x",
+      "composite": {
+        "fields": [
+          {
+            "name": "y",
+            "primary": {
+              "value": {
+                "range": "d2/testdata/d2ir/TestCompile/roots/field/label/nested.d2,0:5:5-0:8:8",
+                "value": [
+                  {
+                    "string": "yes",
+                    "raw_string": "yes"
+                  }
+                ]
+              }
+            }
+          }
+        ],
+        "edges": null
+      }
+    }
+  ],
+  "edges": null
+}
diff --git a/testdata/d2ir/TestCompile/roots/nested.exp.json b/testdata/d2ir/TestCompile/roots/nested.exp.json
new file mode 100644
index 000000000..8f8b60261
--- /dev/null
+++ b/testdata/d2ir/TestCompile/roots/nested.exp.json
@@ -0,0 +1,43 @@
+{
+  "fields": [
+    {
+      "name": "x",
+      "composite": {
+        "fields": [
+          {
+            "name": "y"
+          }
+        ],
+        "edges": null
+      }
+    },
+    {
+      "name": "z",
+      "composite": {
+        "fields": [
+          {
+            "name": "p"
+          }
+        ],
+        "edges": null
+      }
+    }
+  ],
+  "edges": [
+    {
+      "edge_id": {
+        "src_path": [
+          "x",
+          "y"
+        ],
+        "src_arrow": false,
+        "dst_path": [
+          "z",
+          "p"
+        ],
+        "dst_arrow": true,
+        "index": 0
+      }
+    }
+  ]
+}
diff --git a/testdata/d2ir/TestCompile/roots/primary.exp.json b/testdata/d2ir/TestCompile/roots/primary.exp.json
new file mode 100644
index 000000000..4e3e9b221
--- /dev/null
+++ b/testdata/d2ir/TestCompile/roots/primary.exp.json
@@ -0,0 +1,27 @@
+{
+  "fields": [
+    {
+      "name": "x",
+      "primary": {
+        "value": {
+          "range": "d2/testdata/d2ir/TestCompile/roots/primary.d2,0:3:3-0:6:6",
+          "value": [
+            {
+              "string": "yes",
+              "raw_string": "yes"
+            }
+          ]
+        }
+      },
+      "composite": {
+        "fields": [
+          {
+            "name": "pqrs"
+          }
+        ],
+        "edges": null
+      }
+    }
+  ],
+  "edges": null
+}
diff --git a/testdata/d2ir/TestCompile/roots/primary/nested.exp.json b/testdata/d2ir/TestCompile/roots/primary/nested.exp.json
new file mode 100644
index 000000000..8ae714eba
--- /dev/null
+++ b/testdata/d2ir/TestCompile/roots/primary/nested.exp.json
@@ -0,0 +1,35 @@
+{
+  "fields": [
+    {
+      "name": "x",
+      "composite": {
+        "fields": [
+          {
+            "name": "y",
+            "primary": {
+              "value": {
+                "range": "d2/testdata/d2ir/TestCompile/roots/primary/nested.d2,0:5:5-0:8:8",
+                "value": [
+                  {
+                    "string": "yes",
+                    "raw_string": "yes"
+                  }
+                ]
+              }
+            },
+            "composite": {
+              "fields": [
+                {
+                  "name": "pqrs"
+                }
+              ],
+              "edges": null
+            }
+          }
+        ],
+        "edges": null
+      }
+    }
+  ],
+  "edges": null
+}
diff --git a/testdata/d2ir/TestCompile/roots/underscore_parent.exp.json b/testdata/d2ir/TestCompile/roots/underscore_parent.exp.json
new file mode 100644
index 000000000..0a718ea3d
--- /dev/null
+++ b/testdata/d2ir/TestCompile/roots/underscore_parent.exp.json
@@ -0,0 +1,34 @@
+{
+  "fields": [
+    {
+      "name": "x",
+      "composite": {
+        "fields": [
+          {
+            "name": "_"
+          }
+        ],
+        "edges": null
+      }
+    },
+    {
+      "name": "z"
+    }
+  ],
+  "edges": [
+    {
+      "edge_id": {
+        "src_path": [
+          "x",
+          "_"
+        ],
+        "src_arrow": false,
+        "dst_path": [
+          "z"
+        ],
+        "dst_arrow": true,
+        "index": 0
+      }
+    }
+  ]
+}
diff --git a/testdata/d2ir/TestCompile/simple/edge.exp.json b/testdata/d2ir/TestCompile/simple/edge.exp.json
new file mode 100644
index 000000000..fbfc21849
--- /dev/null
+++ b/testdata/d2ir/TestCompile/simple/edge.exp.json
@@ -0,0 +1,4 @@
+{
+  "fields": null,
+  "edges": null
+}
diff --git a/testdata/d2ir/TestCompile/simple/field.exp.json b/testdata/d2ir/TestCompile/simple/field.exp.json
new file mode 100644
index 000000000..2dcf9ab44
--- /dev/null
+++ b/testdata/d2ir/TestCompile/simple/field.exp.json
@@ -0,0 +1,8 @@
+{
+  "fields": [
+    {
+      "name": "x"
+    }
+  ],
+  "edges": null
+}
diff --git a/testdata/d2ir/TestCompile/simple/field/label.exp.json b/testdata/d2ir/TestCompile/simple/field/label.exp.json
new file mode 100644
index 000000000..17ebacf95
--- /dev/null
+++ b/testdata/d2ir/TestCompile/simple/field/label.exp.json
@@ -0,0 +1,19 @@
+{
+  "fields": [
+    {
+      "name": "x",
+      "primary": {
+        "value": {
+          "range": "d2/testdata/d2ir/TestCompile/simple/field/label.d2,0:3:3-0:6:6",
+          "value": [
+            {
+              "string": "yes",
+              "raw_string": "yes"
+            }
+          ]
+        }
+      }
+    }
+  ],
+  "edges": null
+}
diff --git a/testdata/d2ir/TestCompile/simple/field/label/nested.exp.json b/testdata/d2ir/TestCompile/simple/field/label/nested.exp.json
new file mode 100644
index 000000000..520e48db0
--- /dev/null
+++ b/testdata/d2ir/TestCompile/simple/field/label/nested.exp.json
@@ -0,0 +1,27 @@
+{
+  "fields": [
+    {
+      "name": "x",
+      "composite": {
+        "fields": [
+          {
+            "name": "y",
+            "primary": {
+              "value": {
+                "range": "d2/testdata/d2ir/TestCompile/simple/field/label/nested.d2,0:5:5-0:8:8",
+                "value": [
+                  {
+                    "string": "yes",
+                    "raw_string": "yes"
+                  }
+                ]
+              }
+            }
+          }
+        ],
+        "edges": null
+      }
+    }
+  ],
+  "edges": null
+}
diff --git a/testdata/d2ir/TestCompile/simple/nested.exp.json b/testdata/d2ir/TestCompile/simple/nested.exp.json
new file mode 100644
index 000000000..fbfc21849
--- /dev/null
+++ b/testdata/d2ir/TestCompile/simple/nested.exp.json
@@ -0,0 +1,4 @@
+{
+  "fields": null,
+  "edges": null
+}
diff --git a/testdata/d2ir/TestCompile/simple/primary.exp.json b/testdata/d2ir/TestCompile/simple/primary.exp.json
new file mode 100644
index 000000000..d104b375d
--- /dev/null
+++ b/testdata/d2ir/TestCompile/simple/primary.exp.json
@@ -0,0 +1,27 @@
+{
+  "fields": [
+    {
+      "name": "x",
+      "primary": {
+        "value": {
+          "range": "d2/testdata/d2ir/TestCompile/simple/primary.d2,0:3:3-0:6:6",
+          "value": [
+            {
+              "string": "yes",
+              "raw_string": "yes"
+            }
+          ]
+        }
+      },
+      "composite": {
+        "fields": [
+          {
+            "name": "pqrs"
+          }
+        ],
+        "edges": null
+      }
+    }
+  ],
+  "edges": null
+}
diff --git a/testdata/d2ir/TestCompile/simple/primary/nested.exp.json b/testdata/d2ir/TestCompile/simple/primary/nested.exp.json
new file mode 100644
index 000000000..ebac9bea8
--- /dev/null
+++ b/testdata/d2ir/TestCompile/simple/primary/nested.exp.json
@@ -0,0 +1,35 @@
+{
+  "fields": [
+    {
+      "name": "x",
+      "composite": {
+        "fields": [
+          {
+            "name": "y",
+            "primary": {
+              "value": {
+                "range": "d2/testdata/d2ir/TestCompile/simple/primary/nested.d2,0:5:5-0:8:8",
+                "value": [
+                  {
+                    "string": "yes",
+                    "raw_string": "yes"
+                  }
+                ]
+              }
+            },
+            "composite": {
+              "fields": [
+                {
+                  "name": "pqrs"
+                }
+              ],
+              "edges": null
+            }
+          }
+        ],
+        "edges": null
+      }
+    }
+  ],
+  "edges": null
+}
diff --git a/testdata/d2ir/TestCompile/simple/underscore_parent.exp.json b/testdata/d2ir/TestCompile/simple/underscore_parent.exp.json
new file mode 100644
index 000000000..fbfc21849
--- /dev/null
+++ b/testdata/d2ir/TestCompile/simple/underscore_parent.exp.json
@@ -0,0 +1,4 @@
+{
+  "fields": null,
+  "edges": null
+}