Support local tag and boolean tag (#527)

* support local tag and boolean tag

* add test case

decode.go

@@ -13,6 +13,7 @@ import (
 	"reflect"
 	"sort"
 	"strconv"
+	"strings"
 	"time"
 
 	"github.com/goccy/go-yaml/ast"
@@ -332,10 +333,29 @@ func (d *Decoder) nodeToValue(node ast.Node) (any, error) {
 			}
 			b, _ := base64.StdEncoding.DecodeString(v.(string))
 			return b, nil
+		case token.BooleanTag:
+			v, err := d.nodeToValue(n.Value)
+			if err != nil {
+				return nil, err
+			}
+			str := strings.ToLower(fmt.Sprint(v))
+			b, err := strconv.ParseBool(str)
+			if err == nil {
+				return b, nil
+			}
+			switch str {
+			case "yes":
+				return true, nil
+			case "no":
+				return false, nil
+			}
+			return nil, errors.ErrSyntax(fmt.Sprintf("cannot convert %q to boolean", fmt.Sprint(v)), n.Value.GetToken())
 		case token.StringTag:
 			return d.nodeToValue(n.Value)
 		case token.MappingTag:
 			return d.nodeToValue(n.Value)
+		default:
+			return d.nodeToValue(n.Value)
 		}
 	case *ast.AnchorNode:
 		anchorName := n.Name.GetToken().Value

decode_test.go

@@ -582,6 +582,14 @@ func TestDecoder(t *testing.T) {
 			"v: !!timestamp 2015-01-01",
 			map[string]time.Time{"v": time.Date(2015, 1, 1, 0, 0, 0, 0, time.UTC)},
 		},
+		{
+			"v: !!bool yes",
+			map[string]bool{"v": true},
+		},
+		{
+			"v: !!bool False",
+			map[string]bool{"v": false},
+		},
 
 		// Flow sequence
 		{

parser/parser.go

@@ -241,6 +241,7 @@ func (p *parser) parseTag(ctx *context) (*ast.TagNode, error) {
 		token.StringTag,
 		token.BinaryTag,
 		token.TimestampTag,
+		token.BooleanTag,
 		token.NullTag:
 		typ := p.currentToken().Type
 		if typ == token.LiteralType || typ == token.FoldedType {
@@ -252,7 +253,11 @@ func (p *parser) parseTag(ctx *context) (*ast.TagNode, error) {
 		token.SetTag:
 		err = errors.ErrSyntax(fmt.Sprintf("sorry, currently not supported %s tag", tagToken.Value), tagToken)
 	default:
-		err = errors.ErrSyntax(fmt.Sprintf("unknown tag name %q specified", tagToken.Value), tagToken)
+		if strings.HasPrefix(tagToken.Value, "!!") {
+			err = errors.ErrSyntax(fmt.Sprintf("unknown secondary tag name %q specified", tagToken.Value), tagToken)
+		} else {
+			value, err = p.parseToken(ctx, p.currentToken())
+		}
 	}
 	if err != nil {
 		return nil, err

parser/parser_test.go

@@ -114,6 +114,20 @@ func TestParser(t *testing.T) {
   a: {
     b: c
   }}
+`,
+		`
+- !tag
+  a: b
+  c: d
+`,
+		`
+a: !tag
+  b: c
+`,
+		`
+a: !tag
+  b: c
+  d: e
 `,
 	}
 	for _, src := range sources {
@@ -958,41 +972,12 @@ func TestSyntaxError(t *testing.T) {
 		expect string
 	}{
 		{
+			`v: !!int64 2`,
 			`
-- !tag
-  a: b
-  c: d
-`,
-			`
-[2:3] unknown tag name "!tag" specified
->  2 | - !tag
-         ^
-   3 |   a: b
-   4 |   c: d`,
-		},
-		{
-			`
-a: !tag
-  b: c
-`,
-			`
-[2:4] unknown tag name "!tag" specified
->  2 | a: !tag
+[1:4] unknown secondary tag name "!!int64" specified
+>  1 | v: !!int64 2
           ^
-   3 |   b: c`,
-		},
-		{
-			`
-a: !tag
-  b: c
-  d: e
 `,
-			`
-[2:4] unknown tag name "!tag" specified
->  2 | a: !tag
-          ^
-   3 |   b: c
-   4 |   d: e`,
 		},
 		{
 			`

token/token.go

@@ -401,6 +401,8 @@ const (
 	SetTag ReservedTagKeyword = "!!set"
 	// TimestampTag `!!timestamp` tag
 	TimestampTag ReservedTagKeyword = "!!timestamp"
+	// BooleanTag `!!bool` tag
+	BooleanTag ReservedTagKeyword = "!!bool"
 )
 
 var (
@@ -506,6 +508,16 @@ var (
 				Position:      pos,
 			}
 		},
+		BooleanTag: func(value, org string, pos *Position) *Token {
+			return &Token{
+				Type:          TagType,
+				CharacterType: CharacterTypeIndicator,
+				Indicator:     NodePropertyIndicator,
+				Value:         value,
+				Origin:        org,
+				Position:      pos,
+			}
+		},
 	}
 )