Add support for Nodes

_tests/basic.hcl

@@ -5,3 +5,5 @@ Int = 123
 Bool = true
 
 Float = 4.56
+
+Node = baz

_tests/nested-struct-slice-no-key.hcl

@@ -2,6 +2,9 @@ Widget = [
   {
     Foo = "bar"
   },
+  {
+    Bar = fizz
+  },
   {
     Foo = "baz"
   },

_tests/nested-structs.hcl

@@ -5,3 +5,8 @@ Foo {
 Fizz {
   Buzz = 1.23
 }
+
+Bar {
+  Bar  = baz
+  Fizz = "bar"
+}

hclencoder.go

@@ -10,7 +10,7 @@ import (
 
 // Encode converts any supported type into the corresponding HCL format
 func Encode(in interface{}) ([]byte, error) {
-	node, _, err := encode(reflect.ValueOf(in))
+	node, _, err := encode(reflect.ValueOf(in), false)
 	if err != nil {
 		return nil, err
 	}

hclencoder_test.go

@@ -29,11 +29,13 @@ func TestEncoder(t *testing.T) {
 				Int    int
 				Bool   bool
 				Float  float64
+				Node   string `hcle:"node"`
 			}{
 				"bar",
 				123,
 				true,
 				4.56,
+				"baz",
 			},
 			Output: "basic",
 		},
@@ -66,9 +68,17 @@ func TestEncoder(t *testing.T) {
 			Input: struct {
 				Foo  struct{ Bar string }
 				Fizz struct{ Buzz float64 }
+				Bar  struct {
+					Bar  string `hcle:"node"`
+					Fizz string
+				}
 			}{
 				struct{ Bar string }{Bar: "baz"},
 				struct{ Buzz float64 }{Buzz: 1.23},
+				struct {
+					Bar  string `hcle:"node"`
+					Fizz string
+				}{Bar: "baz", Fizz: "bar"},
 			},
 			Output: "nested-structs",
 		},
@@ -131,14 +141,17 @@ func TestEncoder(t *testing.T) {
 			ID: "nested struct slice no key",
 			Input: struct {
 				Widget []struct {
-					Foo string
+					Foo string `hcle:"omitempty"`
+					Bar string `hcle:"omitempty,node"`
 				}
 			}{
 				Widget: []struct {
-					Foo string
+					Foo string `hcle:"omitempty"`
+					Bar string `hcle:"omitempty,node"`
 				}{
-					{"bar"},
-					{"baz"},
+					{"bar", ""},
+					{"", "fizz"},
+					{"baz", ""},
 				},
 			},
 			Output: "nested-struct-slice-no-key",

nodes.go

@@ -48,6 +48,9 @@ const (
 	// OmitEmptyTag will omit this field if it is a zero value. This
 	// is similar behavior to `json:",omitempty"`
 	OmitEmptyTag string = "omitempty"
+
+	// Node will omit quotes from the output, useful for references.
+	Node string = "node"
 )
 
 type fieldMeta struct {
@@ -59,10 +62,11 @@ type fieldMeta struct {
 	decodedFields bool
 	omit          bool
 	omitEmpty     bool
+	node          bool
 }
 
 // encode converts a reflected valued into an HCL ast.Node in a depth-first manner.
-func encode(in reflect.Value) (node ast.Node, key []*ast.ObjectKey, err error) {
+func encode(in reflect.Value, isNode bool) (node ast.Node, key []*ast.ObjectKey, err error) {
 	in, isNil := deref(in)
 	if isNil {
 		return nil, nil, nil
@@ -73,16 +77,16 @@ func encode(in reflect.Value) (node ast.Node, key []*ast.ObjectKey, err error) {
 	case reflect.Bool, reflect.Float64, reflect.String,
 		reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64,
 		reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
-		return encodePrimitive(in)
+		return encodePrimitive(in, isNode)
 
 	case reflect.Slice:
-		return encodeList(in)
+		return encodeList(in, isNode)
 
 	case reflect.Map:
-		return encodeMap(in)
+		return encodeMap(in, isNode)
 
 	case reflect.Struct:
-		return encodeStruct(in)
+		return encodeStruct(in, isNode)
 
 	default:
 		return nil, nil, fmt.Errorf("cannot encode kind %s to HCL", in.Kind())
@@ -92,8 +96,8 @@ func encode(in reflect.Value) (node ast.Node, key []*ast.ObjectKey, err error) {
 
 // encodePrimitive converts a primitive value into an ast.LiteralType. An
 // ast.ObjectKey is never returned.
-func encodePrimitive(in reflect.Value) (ast.Node, []*ast.ObjectKey, error) {
-	tkn, err := tokenize(in, false)
+func encodePrimitive(in reflect.Value, isNode bool) (ast.Node, []*ast.ObjectKey, error) {
+	tkn, err := tokenize(in, isNode)
 	if err != nil {
 		return nil, nil, err
 	}
@@ -103,7 +107,7 @@ func encodePrimitive(in reflect.Value) (ast.Node, []*ast.ObjectKey, error) {
 
 // encodeList converts a slice to an appropriate ast.Node type depending on its
 // element value type. An ast.ObjectKey is never returned.
-func encodeList(in reflect.Value) (ast.Node, []*ast.ObjectKey, error) {
+func encodeList(in reflect.Value, isNode bool) (ast.Node, []*ast.ObjectKey, error) {
 	childType := in.Type().Elem()
 
 childLoop:
@@ -118,20 +122,20 @@ childLoop:
 
 	switch childType.Kind() {
 	case reflect.Map, reflect.Struct, reflect.Interface:
-		return encodeBlockList(in)
+		return encodeBlockList(in, isNode)
 	default:
-		return encodePrimitiveList(in)
+		return encodePrimitiveList(in, isNode)
 	}
 }
 
 // encodePrimitiveList converts a slice of primitive values to an ast.ListType. An
 // ast.ObjectKey is never returned.
-func encodePrimitiveList(in reflect.Value) (ast.Node, []*ast.ObjectKey, error) {
+func encodePrimitiveList(in reflect.Value, isNode bool) (ast.Node, []*ast.ObjectKey, error) {
 	l := in.Len()
 	n := &ast.ListType{List: make([]ast.Node, 0, l)}
 
 	for i := 0; i < l; i++ {
-		child, _, err := encode(in.Index(i))
+		child, _, err := encode(in.Index(i), isNode)
 		if err != nil {
 			return nil, nil, err
 		}
@@ -145,20 +149,20 @@ func encodePrimitiveList(in reflect.Value) (ast.Node, []*ast.ObjectKey, error) {
 
 // encodeBlockList converts a slice of non-primitive types to an ast.ObjectList. An
 // ast.ObjectKey is never returned.
-func encodeBlockList(in reflect.Value) (ast.Node, []*ast.ObjectKey, error) {
+func encodeBlockList(in reflect.Value, isNode bool) (ast.Node, []*ast.ObjectKey, error) {
 	l := in.Len()
 	n := &ast.ObjectList{Items: make([]*ast.ObjectItem, 0, l)}
 
 	for i := 0; i < l; i++ {
-		child, childKey, err := encode(in.Index(i))
+		child, childKey, err := encode(in.Index(i), isNode)
 		if err != nil {
 			return nil, nil, err
 		}
 		if child == nil {
 			continue
 		}
 		if childKey == nil {
-			return encodePrimitiveList(in)
+			return encodePrimitiveList(in, isNode)
 		}
 
 		item := &ast.ObjectItem{Val: child}
@@ -171,7 +175,7 @@ func encodeBlockList(in reflect.Value) (ast.Node, []*ast.ObjectKey, error) {
 
 // encodeMap converts a map type into an ast.ObjectType. Maps must have string
 // key values to be encoded. An ast.ObjectKey is never returned.
-func encodeMap(in reflect.Value) (ast.Node, []*ast.ObjectKey, error) {
+func encodeMap(in reflect.Value, isNode bool) (ast.Node, []*ast.ObjectKey, error) {
 	if keyType := in.Type().Key().Kind(); keyType != reflect.String {
 		return nil, nil, fmt.Errorf("map keys must be strings, %s given", keyType)
 	}
@@ -180,7 +184,7 @@ func encodeMap(in reflect.Value) (ast.Node, []*ast.ObjectKey, error) {
 	for _, key := range in.MapKeys() {
 		tkn, _ := tokenize(key, true) // error impossible since we've already checked key kind
 
-		val, childKey, err := encode(in.MapIndex(key))
+		val, childKey, err := encode(in.MapIndex(key), isNode)
 		if err != nil {
 			return nil, nil, err
 		}
@@ -222,7 +226,7 @@ func encodeMap(in reflect.Value) (ast.Node, []*ast.ObjectKey, error) {
 // encodeStruct converts a struct type into an ast.ObjectType. An ast.ObjectKey
 // may be returned if a KeyTag is present that should be used by a parent
 // ast.ObjectItem if this node is nested.
-func encodeStruct(in reflect.Value) (ast.Node, []*ast.ObjectKey, error) {
+func encodeStruct(in reflect.Value, isNode bool) (ast.Node, []*ast.ObjectKey, error) {
 	l := in.NumField()
 	list := &ast.ObjectList{Items: make([]*ast.ObjectItem, 0, l)}
 	keys := make([]*ast.ObjectKey, 0)
@@ -248,7 +252,7 @@ func encodeStruct(in reflect.Value) (ast.Node, []*ast.ObjectKey, error) {
 			}
 		}
 
-		val, childKeys, err := encode(rawVal)
+		val, childKeys, err := encode(rawVal, meta.node)
 		if err != nil {
 			return nil, nil, err
 		}
@@ -386,6 +390,8 @@ func extractFieldMeta(f reflect.StructField) (meta fieldMeta) {
 			meta.omit = true
 		case OmitEmptyTag:
 			meta.omitEmpty = true
+		case Node:
+			meta.node = true
 		}
 	}
 

nodes_test.go

@@ -10,18 +10,19 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-type encodeFunc func(reflect.Value) (ast.Node, []*ast.ObjectKey, error)
+type encodeFunc func(reflect.Value, bool) (ast.Node, []*ast.ObjectKey, error)
 
 type encodeTest struct {
 	ID       string
 	Input    reflect.Value
+	Node     bool
 	Expected ast.Node
 	Key      []*ast.ObjectKey
 	Error    bool
 }
 
 func (test encodeTest) Test(f encodeFunc, t *testing.T) (node ast.Node, key []*ast.ObjectKey, err error) {
-	node, key, err = f(test.Input)
+	node, key, err = f(test.Input, test.Node)
 
 	if test.Error {
 		assert.Error(t, err, test.ID)
@@ -113,6 +114,12 @@ func TestEncodePrimitive(t *testing.T) {
 			Input:    reflect.ValueOf("foobar"),
 			Expected: &ast.LiteralType{Token: token.Token{Type: token.STRING, Text: `"foobar"`}},
 		},
+		{
+			ID:       "string - always ident",
+			Input:    reflect.ValueOf("foobar"),
+			Node:     true,
+			Expected: &ast.LiteralType{Token: token.Token{Type: token.IDENT, Text: `foobar`}},
+		},
 		{
 			ID:       "uint",
 			Input:    reflect.ValueOf(uint(1)),
@@ -350,6 +357,7 @@ func TestEncodeStruct(t *testing.T) {
 				},
 			}}},
 		},
+
 		{
 			ID:       "debug fields",
 			Input:    reflect.ValueOf(DebugStruct{Decoded: []string{}, Unused: []string{}}),
@@ -546,6 +554,10 @@ func TestExtractFieldMeta(t *testing.T) {
 			`hcle:"omitempty"`,
 			fieldMeta{name: fieldName, omitEmpty: true},
 		},
+		{
+			`hcle:"node"`,
+			fieldMeta{name: fieldName, node: true},
+		},
 	}
 
 	for _, test := range tests {

readme.md

@@ -16,8 +16,9 @@ type Farmer struct {
 }
 
 type Animal struct {
-  Name  string `hcl:",key"`
-  Sound string `hcl:"says" hcle:"omitempty"`
+  Name     string `hcl:",key"`
+  Sound    string `hcl:"says" hcle:"omitempty"`
+  Category string `hcle:"node"`
 }
 
 type Config struct {
@@ -42,13 +43,16 @@ input := Config{
     {
       Name:  "cow",
       Sound: "moo",
+      Category: "data.animal_categories.cow"
     },
     {
       Name:  "pig",
       Sound: "oink",
+      Category: "data.animal_categories.pig"
     },
     {
       Name: "rock",
+      Category: "data.animal_categories.rock"
     },
   },
   Buildings: map[string]string{
@@ -81,13 +85,17 @@ fmt.Print(string(hcl))
 //
 // animal "cow" {
 //   says = "moo"
+//   category = data.animal_categories.cow
 // }
 //
 // animal "pig" {
 //   says = "oink"
+//   category = data.animal_categories.pig
 // }
 //
-// animal "rock" {}
+// animal "rock" {
+//   category = data.animal_categories.rock
+// }
 //
 // buildings {
 //   Barn  = "456 Digits Drive"
@@ -126,6 +134,8 @@ fmt.Print(string(hcl))
 
 - **`hcle:"omitempty"`** - omits this field if it is a zero value for its type. This is similar behavior to [`json:",omitempty"`][json].
 
+- **`hcle:"node"`** - node will omit quotes from the output, useful for references.
+
 [HCL]:         https://github.com/hashicorp/hcl
 [hclprinter]:  https://godoc.org/github.com/hashicorp/hcl/hcl/printer
 [json]:        https://golang.org/pkg/encoding/json/#Marshal

script/test

@@ -13,7 +13,7 @@ echo "go lint..."
 test -z "$(golint ./... | tee /dev/stderr)"
 
 echo "go vet..."
-test -z "$(go tool vet -all -shadow . 2>&1 | tee /dev/stderr)"
+test -z "$(go vet -all . 2>&1 | tee /dev/stderr)"
 
 echo "go test..."
 go test -race -cover ./...