chore: migrate to gitea

vendor/github.com/goccy/go-yaml/parser/color.go

@@ -0,0 +1,28 @@
+package parser
+
+import "fmt"
+
+const (
+	colorFgHiBlack int = iota + 90
+	colorFgHiRed
+	colorFgHiGreen
+	colorFgHiYellow
+	colorFgHiBlue
+	colorFgHiMagenta
+	colorFgHiCyan
+)
+
+var colorTable = []int{
+	colorFgHiRed,
+	colorFgHiGreen,
+	colorFgHiYellow,
+	colorFgHiBlue,
+	colorFgHiMagenta,
+	colorFgHiCyan,
+}
+
+func colorize(idx int, content string) string {
+	colorIdx := idx % len(colorTable)
+	color := colorTable[colorIdx]
+	return fmt.Sprintf("\x1b[1;%dm", color) + content + "\x1b[22;0m"
+}

vendor/github.com/goccy/go-yaml/parser/context.go

@@ -0,0 +1,187 @@
+package parser
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/goccy/go-yaml/token"
+)
+
+// context context at parsing
+type context struct {
+	tokenRef *tokenRef
+	path     string
+	isFlow   bool
+}
+
+type tokenRef struct {
+	tokens []*Token
+	size   int
+	idx    int
+}
+
+var pathSpecialChars = []string{
+	"$", "*", ".", "[", "]",
+}
+
+func containsPathSpecialChar(path string) bool {
+	for _, char := range pathSpecialChars {
+		if strings.Contains(path, char) {
+			return true
+		}
+	}
+	return false
+}
+
+func normalizePath(path string) string {
+	if containsPathSpecialChar(path) {
+		return fmt.Sprintf("'%s'", path)
+	}
+	return path
+}
+
+func (c *context) currentToken() *Token {
+	if c.tokenRef.idx >= c.tokenRef.size {
+		return nil
+	}
+	return c.tokenRef.tokens[c.tokenRef.idx]
+}
+
+func (c *context) isComment() bool {
+	return c.currentToken().Type() == token.CommentType
+}
+
+func (c *context) nextToken() *Token {
+	if c.tokenRef.idx+1 >= c.tokenRef.size {
+		return nil
+	}
+	return c.tokenRef.tokens[c.tokenRef.idx+1]
+}
+
+func (c *context) nextNotCommentToken() *Token {
+	for i := c.tokenRef.idx + 1; i < c.tokenRef.size; i++ {
+		tk := c.tokenRef.tokens[i]
+		if tk.Type() == token.CommentType {
+			continue
+		}
+		return tk
+	}
+	return nil
+}
+
+func (c *context) isTokenNotFound() bool {
+	return c.currentToken() == nil
+}
+
+func (c *context) withGroup(g *TokenGroup) *context {
+	ctx := *c
+	ctx.tokenRef = &tokenRef{
+		tokens: g.Tokens,
+		size:   len(g.Tokens),
+	}
+	return &ctx
+}
+
+func (c *context) withChild(path string) *context {
+	ctx := *c
+	ctx.path = c.path + "." + normalizePath(path)
+	return &ctx
+}
+
+func (c *context) withIndex(idx uint) *context {
+	ctx := *c
+	ctx.path = c.path + "[" + fmt.Sprint(idx) + "]"
+	return &ctx
+}
+
+func (c *context) withFlow(isFlow bool) *context {
+	ctx := *c
+	ctx.isFlow = isFlow
+	return &ctx
+}
+
+func newContext() *context {
+	return &context{
+		path: "$",
+	}
+}
+
+func (c *context) goNext() {
+	ref := c.tokenRef
+	if ref.size <= ref.idx+1 {
+		ref.idx = ref.size
+	} else {
+		ref.idx++
+	}
+}
+
+func (c *context) next() bool {
+	return c.tokenRef.idx < c.tokenRef.size
+}
+
+func (c *context) insertNullToken(tk *Token) *Token {
+	nullToken := c.createImplicitNullToken(tk)
+	c.insertToken(nullToken)
+	c.goNext()
+
+	return nullToken
+}
+
+func (c *context) addNullValueToken(tk *Token) *Token {
+	nullToken := c.createImplicitNullToken(tk)
+	rawTk := nullToken.RawToken()
+
+	// add space for map or sequence value.
+	rawTk.Position.Column++
+
+	c.addToken(nullToken)
+	c.goNext()
+
+	return nullToken
+}
+
+func (c *context) createImplicitNullToken(base *Token) *Token {
+	pos := *(base.RawToken().Position)
+	pos.Column++
+	tk := token.New("null", " null", &pos)
+	tk.Type = token.ImplicitNullType
+	return &Token{Token: tk}
+}
+
+func (c *context) insertToken(tk *Token) {
+	ref := c.tokenRef
+	idx := ref.idx
+	if ref.size < idx {
+		return
+	}
+	if ref.size == idx {
+		curToken := ref.tokens[ref.size-1]
+		tk.RawToken().Next = curToken.RawToken()
+		curToken.RawToken().Prev = tk.RawToken()
+
+		ref.tokens = append(ref.tokens, tk)
+		ref.size = len(ref.tokens)
+		return
+	}
+
+	curToken := ref.tokens[idx]
+	tk.RawToken().Next = curToken.RawToken()
+	curToken.RawToken().Prev = tk.RawToken()
+
+	ref.tokens = append(ref.tokens[:idx+1], ref.tokens[idx:]...)
+	ref.tokens[idx] = tk
+	ref.size = len(ref.tokens)
+}
+
+func (c *context) addToken(tk *Token) {
+	ref := c.tokenRef
+	lastTk := ref.tokens[ref.size-1]
+	if lastTk.Group != nil {
+		lastTk = lastTk.Group.Last()
+	}
+	lastTk.RawToken().Next = tk.RawToken()
+	tk.RawToken().Prev = lastTk.RawToken()
+
+	ref.tokens = append(ref.tokens, tk)
+	ref.size = len(ref.tokens)
+}

vendor/github.com/goccy/go-yaml/parser/node.go

@@ -0,0 +1,257 @@
+package parser
+
+import (
+	"fmt"
+
+	"github.com/goccy/go-yaml/ast"
+	"github.com/goccy/go-yaml/internal/errors"
+	"github.com/goccy/go-yaml/token"
+)
+
+func newMappingNode(ctx *context, tk *Token, isFlow bool, values ...*ast.MappingValueNode) (*ast.MappingNode, error) {
+	node := ast.Mapping(tk.RawToken(), isFlow, values...)
+	node.SetPath(ctx.path)
+	return node, nil
+}
+
+func newMappingValueNode(ctx *context, colonTk, entryTk *Token, key ast.MapKeyNode, value ast.Node) (*ast.MappingValueNode, error) {
+	node := ast.MappingValue(colonTk.RawToken(), key, value)
+	node.SetPath(ctx.path)
+	node.CollectEntry = entryTk.RawToken()
+	if key.GetToken().Position.Line == value.GetToken().Position.Line {
+		// originally key was commented, but now that null value has been added, value must be commented.
+		if err := setLineComment(ctx, value, colonTk); err != nil {
+			return nil, err
+		}
+		// set line comment by colonTk or entryTk.
+		if err := setLineComment(ctx, value, entryTk); err != nil {
+			return nil, err
+		}
+	} else {
+		if err := setLineComment(ctx, key, colonTk); err != nil {
+			return nil, err
+		}
+		// set line comment by colonTk or entryTk.
+		if err := setLineComment(ctx, key, entryTk); err != nil {
+			return nil, err
+		}
+	}
+	return node, nil
+}
+
+func newMappingKeyNode(ctx *context, tk *Token) (*ast.MappingKeyNode, error) {
+	node := ast.MappingKey(tk.RawToken())
+	node.SetPath(ctx.path)
+	if err := setLineComment(ctx, node, tk); err != nil {
+		return nil, err
+	}
+	return node, nil
+}
+
+func newAnchorNode(ctx *context, tk *Token) (*ast.AnchorNode, error) {
+	node := ast.Anchor(tk.RawToken())
+	node.SetPath(ctx.path)
+	if err := setLineComment(ctx, node, tk); err != nil {
+		return nil, err
+	}
+	return node, nil
+}
+
+func newAliasNode(ctx *context, tk *Token) (*ast.AliasNode, error) {
+	node := ast.Alias(tk.RawToken())
+	node.SetPath(ctx.path)
+	if err := setLineComment(ctx, node, tk); err != nil {
+		return nil, err
+	}
+	return node, nil
+}
+
+func newDirectiveNode(ctx *context, tk *Token) (*ast.DirectiveNode, error) {
+	node := ast.Directive(tk.RawToken())
+	node.SetPath(ctx.path)
+	if err := setLineComment(ctx, node, tk); err != nil {
+		return nil, err
+	}
+	return node, nil
+}
+
+func newMergeKeyNode(ctx *context, tk *Token) (*ast.MergeKeyNode, error) {
+	node := ast.MergeKey(tk.RawToken())
+	node.SetPath(ctx.path)
+	if err := setLineComment(ctx, node, tk); err != nil {
+		return nil, err
+	}
+	return node, nil
+}
+
+func newNullNode(ctx *context, tk *Token) (*ast.NullNode, error) {
+	node := ast.Null(tk.RawToken())
+	node.SetPath(ctx.path)
+	if err := setLineComment(ctx, node, tk); err != nil {
+		return nil, err
+	}
+	return node, nil
+}
+
+func newBoolNode(ctx *context, tk *Token) (*ast.BoolNode, error) {
+	node := ast.Bool(tk.RawToken())
+	node.SetPath(ctx.path)
+	if err := setLineComment(ctx, node, tk); err != nil {
+		return nil, err
+	}
+	return node, nil
+}
+
+func newIntegerNode(ctx *context, tk *Token) (*ast.IntegerNode, error) {
+	node := ast.Integer(tk.RawToken())
+	node.SetPath(ctx.path)
+	if err := setLineComment(ctx, node, tk); err != nil {
+		return nil, err
+	}
+	return node, nil
+}
+
+func newFloatNode(ctx *context, tk *Token) (*ast.FloatNode, error) {
+	node := ast.Float(tk.RawToken())
+	node.SetPath(ctx.path)
+	if err := setLineComment(ctx, node, tk); err != nil {
+		return nil, err
+	}
+	return node, nil
+}
+
+func newInfinityNode(ctx *context, tk *Token) (*ast.InfinityNode, error) {
+	node := ast.Infinity(tk.RawToken())
+	node.SetPath(ctx.path)
+	if err := setLineComment(ctx, node, tk); err != nil {
+		return nil, err
+	}
+	return node, nil
+}
+
+func newNanNode(ctx *context, tk *Token) (*ast.NanNode, error) {
+	node := ast.Nan(tk.RawToken())
+	node.SetPath(ctx.path)
+	if err := setLineComment(ctx, node, tk); err != nil {
+		return nil, err
+	}
+	return node, nil
+}
+
+func newStringNode(ctx *context, tk *Token) (*ast.StringNode, error) {
+	node := ast.String(tk.RawToken())
+	node.SetPath(ctx.path)
+	if err := setLineComment(ctx, node, tk); err != nil {
+		return nil, err
+	}
+	return node, nil
+}
+
+func newLiteralNode(ctx *context, tk *Token) (*ast.LiteralNode, error) {
+	node := ast.Literal(tk.RawToken())
+	node.SetPath(ctx.path)
+	if err := setLineComment(ctx, node, tk); err != nil {
+		return nil, err
+	}
+	return node, nil
+}
+
+func newTagNode(ctx *context, tk *Token) (*ast.TagNode, error) {
+	node := ast.Tag(tk.RawToken())
+	node.SetPath(ctx.path)
+	if err := setLineComment(ctx, node, tk); err != nil {
+		return nil, err
+	}
+	return node, nil
+}
+
+func newSequenceNode(ctx *context, tk *Token, isFlow bool) (*ast.SequenceNode, error) {
+	node := ast.Sequence(tk.RawToken(), isFlow)
+	node.SetPath(ctx.path)
+	if err := setLineComment(ctx, node, tk); err != nil {
+		return nil, err
+	}
+	return node, nil
+}
+
+func newTagDefaultScalarValueNode(ctx *context, tag *token.Token) (ast.ScalarNode, error) {
+	pos := *(tag.Position)
+	pos.Column++
+
+	var (
+		tk   *Token
+		node ast.ScalarNode
+	)
+	switch token.ReservedTagKeyword(tag.Value) {
+	case token.IntegerTag:
+		tk = &Token{Token: token.New("0", "0", &pos)}
+		n, err := newIntegerNode(ctx, tk)
+		if err != nil {
+			return nil, err
+		}
+		node = n
+	case token.FloatTag:
+		tk = &Token{Token: token.New("0", "0", &pos)}
+		n, err := newFloatNode(ctx, tk)
+		if err != nil {
+			return nil, err
+		}
+		node = n
+	case token.StringTag, token.BinaryTag, token.TimestampTag:
+		tk = &Token{Token: token.New("", "", &pos)}
+		n, err := newStringNode(ctx, tk)
+		if err != nil {
+			return nil, err
+		}
+		node = n
+	case token.BooleanTag:
+		tk = &Token{Token: token.New("false", "false", &pos)}
+		n, err := newBoolNode(ctx, tk)
+		if err != nil {
+			return nil, err
+		}
+		node = n
+	case token.NullTag:
+		tk = &Token{Token: token.New("null", "null", &pos)}
+		n, err := newNullNode(ctx, tk)
+		if err != nil {
+			return nil, err
+		}
+		node = n
+	default:
+		return nil, errors.ErrSyntax(fmt.Sprintf("cannot assign default value for %q tag", tag.Value), tag)
+	}
+	ctx.insertToken(tk)
+	ctx.goNext()
+	return node, nil
+}
+
+func setLineComment(ctx *context, node ast.Node, tk *Token) error {
+	if tk == nil || tk.LineComment == nil {
+		return nil
+	}
+	comment := ast.CommentGroup([]*token.Token{tk.LineComment})
+	comment.SetPath(ctx.path)
+	if err := node.SetComment(comment); err != nil {
+		return err
+	}
+	return nil
+}
+
+func setHeadComment(cm *ast.CommentGroupNode, value ast.Node) error {
+	if cm == nil {
+		return nil
+	}
+	switch n := value.(type) {
+	case *ast.MappingNode:
+		if len(n.Values) != 0 && value.GetComment() == nil {
+			cm.SetPath(n.Values[0].GetPath())
+			return n.Values[0].SetComment(cm)
+		}
+	case *ast.MappingValueNode:
+		cm.SetPath(n.GetPath())
+		return n.SetComment(cm)
+	}
+	cm.SetPath(value.GetPath())
+	return value.SetComment(cm)
+}

vendor/github.com/goccy/go-yaml/parser/option.go

@@ -0,0 +1,12 @@
+package parser
+
+// Option represents parser's option.
+type Option func(p *parser)
+
+// AllowDuplicateMapKey allow the use of keys with the same name in the same map,
+// but by default, this is not permitted.
+func AllowDuplicateMapKey() Option {
+	return func(p *parser) {
+		p.allowDuplicateMapKey = true
+	}
+}

vendor/github.com/goccy/go-yaml/parser/token.go

@@ -0,0 +1,746 @@
+package parser
+
+import (
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/goccy/go-yaml/internal/errors"
+	"github.com/goccy/go-yaml/token"
+)
+
+type TokenGroupType int
+
+const (
+	TokenGroupNone TokenGroupType = iota
+	TokenGroupDirective
+	TokenGroupDirectiveName
+	TokenGroupDocument
+	TokenGroupDocumentBody
+	TokenGroupAnchor
+	TokenGroupAnchorName
+	TokenGroupAlias
+	TokenGroupLiteral
+	TokenGroupFolded
+	TokenGroupScalarTag
+	TokenGroupMapKey
+	TokenGroupMapKeyValue
+)
+
+func (t TokenGroupType) String() string {
+	switch t {
+	case TokenGroupNone:
+		return "none"
+	case TokenGroupDirective:
+		return "directive"
+	case TokenGroupDirectiveName:
+		return "directive_name"
+	case TokenGroupDocument:
+		return "document"
+	case TokenGroupDocumentBody:
+		return "document_body"
+	case TokenGroupAnchor:
+		return "anchor"
+	case TokenGroupAnchorName:
+		return "anchor_name"
+	case TokenGroupAlias:
+		return "alias"
+	case TokenGroupLiteral:
+		return "literal"
+	case TokenGroupFolded:
+		return "folded"
+	case TokenGroupScalarTag:
+		return "scalar_tag"
+	case TokenGroupMapKey:
+		return "map_key"
+	case TokenGroupMapKeyValue:
+		return "map_key_value"
+	}
+	return "none"
+}
+
+type Token struct {
+	Token       *token.Token
+	Group       *TokenGroup
+	LineComment *token.Token
+}
+
+func (t *Token) RawToken() *token.Token {
+	if t == nil {
+		return nil
+	}
+	if t.Token != nil {
+		return t.Token
+	}
+	return t.Group.RawToken()
+}
+
+func (t *Token) Type() token.Type {
+	if t == nil {
+		return 0
+	}
+	if t.Token != nil {
+		return t.Token.Type
+	}
+	return t.Group.TokenType()
+}
+
+func (t *Token) GroupType() TokenGroupType {
+	if t == nil {
+		return TokenGroupNone
+	}
+	if t.Token != nil {
+		return TokenGroupNone
+	}
+	return t.Group.Type
+}
+
+func (t *Token) Line() int {
+	if t == nil {
+		return 0
+	}
+	if t.Token != nil {
+		return t.Token.Position.Line
+	}
+	return t.Group.Line()
+}
+
+func (t *Token) Column() int {
+	if t == nil {
+		return 0
+	}
+	if t.Token != nil {
+		return t.Token.Position.Column
+	}
+	return t.Group.Column()
+}
+
+func (t *Token) SetGroupType(typ TokenGroupType) {
+	if t.Group == nil {
+		return
+	}
+	t.Group.Type = typ
+}
+
+func (t *Token) Dump() {
+	ctx := new(groupTokenRenderContext)
+	if t.Token != nil {
+		fmt.Fprint(os.Stdout, t.Token.Value)
+		return
+	}
+	t.Group.dump(ctx)
+	fmt.Fprintf(os.Stdout, "\n")
+}
+
+func (t *Token) dump(ctx *groupTokenRenderContext) {
+	if t.Token != nil {
+		fmt.Fprint(os.Stdout, t.Token.Value)
+		return
+	}
+	t.Group.dump(ctx)
+}
+
+type groupTokenRenderContext struct {
+	num int
+}
+
+type TokenGroup struct {
+	Type   TokenGroupType
+	Tokens []*Token
+}
+
+func (g *TokenGroup) First() *Token {
+	if len(g.Tokens) == 0 {
+		return nil
+	}
+	return g.Tokens[0]
+}
+
+func (g *TokenGroup) Last() *Token {
+	if len(g.Tokens) == 0 {
+		return nil
+	}
+	return g.Tokens[len(g.Tokens)-1]
+}
+
+func (g *TokenGroup) dump(ctx *groupTokenRenderContext) {
+	num := ctx.num
+	fmt.Fprint(os.Stdout, colorize(num, "("))
+	ctx.num++
+	for _, tk := range g.Tokens {
+		tk.dump(ctx)
+	}
+	fmt.Fprint(os.Stdout, colorize(num, ")"))
+}
+
+func (g *TokenGroup) RawToken() *token.Token {
+	if len(g.Tokens) == 0 {
+		return nil
+	}
+	return g.Tokens[0].RawToken()
+}
+
+func (g *TokenGroup) Line() int {
+	if len(g.Tokens) == 0 {
+		return 0
+	}
+	return g.Tokens[0].Line()
+}
+
+func (g *TokenGroup) Column() int {
+	if len(g.Tokens) == 0 {
+		return 0
+	}
+	return g.Tokens[0].Column()
+}
+
+func (g *TokenGroup) TokenType() token.Type {
+	if len(g.Tokens) == 0 {
+		return 0
+	}
+	return g.Tokens[0].Type()
+}
+
+func CreateGroupedTokens(tokens token.Tokens) ([]*Token, error) {
+	var err error
+	tks := newTokens(tokens)
+	tks = createLineCommentTokenGroups(tks)
+	tks, err = createLiteralAndFoldedTokenGroups(tks)
+	if err != nil {
+		return nil, err
+	}
+	tks, err = createAnchorAndAliasTokenGroups(tks)
+	if err != nil {
+		return nil, err
+	}
+	tks, err = createScalarTagTokenGroups(tks)
+	if err != nil {
+		return nil, err
+	}
+	tks, err = createAnchorWithScalarTagTokenGroups(tks)
+	if err != nil {
+		return nil, err
+	}
+	tks, err = createMapKeyTokenGroups(tks)
+	if err != nil {
+		return nil, err
+	}
+	tks = createMapKeyValueTokenGroups(tks)
+	tks, err = createDirectiveTokenGroups(tks)
+	if err != nil {
+		return nil, err
+	}
+	tks, err = createDocumentTokens(tks)
+	if err != nil {
+		return nil, err
+	}
+	return tks, nil
+}
+
+func newTokens(tks token.Tokens) []*Token {
+	ret := make([]*Token, 0, len(tks))
+	for _, tk := range tks {
+		ret = append(ret, &Token{Token: tk})
+	}
+	return ret
+}
+
+func createLineCommentTokenGroups(tokens []*Token) []*Token {
+	ret := make([]*Token, 0, len(tokens))
+	for i := 0; i < len(tokens); i++ {
+		tk := tokens[i]
+		switch tk.Type() {
+		case token.CommentType:
+			if i > 0 && tokens[i-1].Line() == tk.Line() {
+				tokens[i-1].LineComment = tk.RawToken()
+			} else {
+				ret = append(ret, tk)
+			}
+		default:
+			ret = append(ret, tk)
+		}
+	}
+	return ret
+}
+
+func createLiteralAndFoldedTokenGroups(tokens []*Token) ([]*Token, error) {
+	ret := make([]*Token, 0, len(tokens))
+	for i := 0; i < len(tokens); i++ {
+		tk := tokens[i]
+		switch tk.Type() {
+		case token.LiteralType:
+			tks := []*Token{tk}
+			if i+1 < len(tokens) {
+				tks = append(tks, tokens[i+1])
+			}
+			ret = append(ret, &Token{
+				Group: &TokenGroup{
+					Type:   TokenGroupLiteral,
+					Tokens: tks,
+				},
+			})
+			i++
+		case token.FoldedType:
+			tks := []*Token{tk}
+			if i+1 < len(tokens) {
+				tks = append(tks, tokens[i+1])
+			}
+			ret = append(ret, &Token{
+				Group: &TokenGroup{
+					Type:   TokenGroupFolded,
+					Tokens: tks,
+				},
+			})
+			i++
+		default:
+			ret = append(ret, tk)
+		}
+	}
+	return ret, nil
+}
+
+func createAnchorAndAliasTokenGroups(tokens []*Token) ([]*Token, error) {
+	ret := make([]*Token, 0, len(tokens))
+	for i := 0; i < len(tokens); i++ {
+		tk := tokens[i]
+		switch tk.Type() {
+		case token.AnchorType:
+			if i+1 >= len(tokens) {
+				return nil, errors.ErrSyntax("undefined anchor name", tk.RawToken())
+			}
+			if i+2 >= len(tokens) {
+				return nil, errors.ErrSyntax("undefined anchor value", tk.RawToken())
+			}
+			anchorName := &Token{
+				Group: &TokenGroup{
+					Type:   TokenGroupAnchorName,
+					Tokens: []*Token{tk, tokens[i+1]},
+				},
+			}
+			valueTk := tokens[i+2]
+			if tk.Line() == valueTk.Line() && valueTk.Type() == token.SequenceEntryType {
+				return nil, errors.ErrSyntax("sequence entries are not allowed after anchor on the same line", valueTk.RawToken())
+			}
+			if tk.Line() == valueTk.Line() && isScalarType(valueTk) {
+				ret = append(ret, &Token{
+					Group: &TokenGroup{
+						Type:   TokenGroupAnchor,
+						Tokens: []*Token{anchorName, valueTk},
+					},
+				})
+				i++
+			} else {
+				ret = append(ret, anchorName)
+			}
+			i++
+		case token.AliasType:
+			if i+1 == len(tokens) {
+				return nil, errors.ErrSyntax("undefined alias name", tk.RawToken())
+			}
+			ret = append(ret, &Token{
+				Group: &TokenGroup{
+					Type:   TokenGroupAlias,
+					Tokens: []*Token{tk, tokens[i+1]},
+				},
+			})
+			i++
+		default:
+			ret = append(ret, tk)
+		}
+	}
+	return ret, nil
+}
+
+func createScalarTagTokenGroups(tokens []*Token) ([]*Token, error) {
+	ret := make([]*Token, 0, len(tokens))
+	for i := 0; i < len(tokens); i++ {
+		tk := tokens[i]
+		if tk.Type() != token.TagType {
+			ret = append(ret, tk)
+			continue
+		}
+		tag := tk.RawToken()
+		if strings.HasPrefix(tag.Value, "!!") {
+			// secondary tag.
+			switch token.ReservedTagKeyword(tag.Value) {
+			case token.IntegerTag, token.FloatTag, token.StringTag, token.BinaryTag, token.TimestampTag, token.BooleanTag, token.NullTag:
+				if len(tokens) <= i+1 {
+					ret = append(ret, tk)
+					continue
+				}
+				if tk.Line() != tokens[i+1].Line() {
+					ret = append(ret, tk)
+					continue
+				}
+				if tokens[i+1].GroupType() == TokenGroupAnchorName {
+					ret = append(ret, tk)
+					continue
+				}
+				if isScalarType(tokens[i+1]) {
+					ret = append(ret, &Token{
+						Group: &TokenGroup{
+							Type:   TokenGroupScalarTag,
+							Tokens: []*Token{tk, tokens[i+1]},
+						},
+					})
+					i++
+				} else {
+					ret = append(ret, tk)
+				}
+			case token.MergeTag:
+				if len(tokens) <= i+1 {
+					ret = append(ret, tk)
+					continue
+				}
+				if tk.Line() != tokens[i+1].Line() {
+					ret = append(ret, tk)
+					continue
+				}
+				if tokens[i+1].GroupType() == TokenGroupAnchorName {
+					ret = append(ret, tk)
+					continue
+				}
+				if tokens[i+1].Type() != token.MergeKeyType {
+					return nil, errors.ErrSyntax("could not find merge key", tokens[i+1].RawToken())
+				}
+				ret = append(ret, &Token{
+					Group: &TokenGroup{
+						Type:   TokenGroupScalarTag,
+						Tokens: []*Token{tk, tokens[i+1]},
+					},
+				})
+				i++
+			default:
+				ret = append(ret, tk)
+			}
+		} else {
+			if len(tokens) <= i+1 {
+				ret = append(ret, tk)
+				continue
+			}
+			if tk.Line() != tokens[i+1].Line() {
+				ret = append(ret, tk)
+				continue
+			}
+			if tokens[i+1].GroupType() == TokenGroupAnchorName {
+				ret = append(ret, tk)
+				continue
+			}
+			if isFlowType(tokens[i+1]) {
+				ret = append(ret, tk)
+				continue
+			}
+			ret = append(ret, &Token{
+				Group: &TokenGroup{
+					Type:   TokenGroupScalarTag,
+					Tokens: []*Token{tk, tokens[i+1]},
+				},
+			})
+			i++
+		}
+	}
+	return ret, nil
+}
+
+func createAnchorWithScalarTagTokenGroups(tokens []*Token) ([]*Token, error) {
+	ret := make([]*Token, 0, len(tokens))
+	for i := 0; i < len(tokens); i++ {
+		tk := tokens[i]
+		switch tk.GroupType() {
+		case TokenGroupAnchorName:
+			if i+1 >= len(tokens) {
+				return nil, errors.ErrSyntax("undefined anchor value", tk.RawToken())
+			}
+			valueTk := tokens[i+1]
+			if tk.Line() == valueTk.Line() && valueTk.GroupType() == TokenGroupScalarTag {
+				ret = append(ret, &Token{
+					Group: &TokenGroup{
+						Type:   TokenGroupAnchor,
+						Tokens: []*Token{tk, tokens[i+1]},
+					},
+				})
+				i++
+			} else {
+				ret = append(ret, tk)
+			}
+		default:
+			ret = append(ret, tk)
+		}
+	}
+	return ret, nil
+}
+
+func createMapKeyTokenGroups(tokens []*Token) ([]*Token, error) {
+	tks, err := createMapKeyByMappingKey(tokens)
+	if err != nil {
+		return nil, err
+	}
+	return createMapKeyByMappingValue(tks)
+}
+
+func createMapKeyByMappingKey(tokens []*Token) ([]*Token, error) {
+	ret := make([]*Token, 0, len(tokens))
+	for i := 0; i < len(tokens); i++ {
+		tk := tokens[i]
+		switch tk.Type() {
+		case token.MappingKeyType:
+			if i+1 >= len(tokens) {
+				return nil, errors.ErrSyntax("undefined map key", tk.RawToken())
+			}
+			ret = append(ret, &Token{
+				Group: &TokenGroup{
+					Type:   TokenGroupMapKey,
+					Tokens: []*Token{tk, tokens[i+1]},
+				},
+			})
+			i++
+		default:
+			ret = append(ret, tk)
+		}
+	}
+	return ret, nil
+}
+
+func createMapKeyByMappingValue(tokens []*Token) ([]*Token, error) {
+	ret := make([]*Token, 0, len(tokens))
+	for i := 0; i < len(tokens); i++ {
+		tk := tokens[i]
+		switch tk.Type() {
+		case token.MappingValueType:
+			if i == 0 {
+				return nil, errors.ErrSyntax("unexpected key name", tk.RawToken())
+			}
+			mapKeyTk := tokens[i-1]
+			if isNotMapKeyType(mapKeyTk) {
+				return nil, errors.ErrSyntax("found an invalid key for this map", tokens[i].RawToken())
+			}
+			newTk := &Token{Token: mapKeyTk.Token, Group: mapKeyTk.Group}
+			mapKeyTk.Token = nil
+			mapKeyTk.Group = &TokenGroup{
+				Type:   TokenGroupMapKey,
+				Tokens: []*Token{newTk, tk},
+			}
+		default:
+			ret = append(ret, tk)
+		}
+	}
+	return ret, nil
+}
+
+func createMapKeyValueTokenGroups(tokens []*Token) []*Token {
+	ret := make([]*Token, 0, len(tokens))
+	for i := 0; i < len(tokens); i++ {
+		tk := tokens[i]
+		switch tk.GroupType() {
+		case TokenGroupMapKey:
+			if len(tokens) <= i+1 {
+				ret = append(ret, tk)
+				continue
+			}
+			valueTk := tokens[i+1]
+			if tk.Line() != valueTk.Line() {
+				ret = append(ret, tk)
+				continue
+			}
+			if valueTk.GroupType() == TokenGroupAnchorName {
+				ret = append(ret, tk)
+				continue
+			}
+			if valueTk.Type() == token.TagType && valueTk.GroupType() != TokenGroupScalarTag {
+				ret = append(ret, tk)
+				continue
+			}
+
+			if isScalarType(valueTk) || valueTk.Type() == token.TagType {
+				ret = append(ret, &Token{
+					Group: &TokenGroup{
+						Type:   TokenGroupMapKeyValue,
+						Tokens: []*Token{tk, valueTk},
+					},
+				})
+				i++
+			} else {
+				ret = append(ret, tk)
+				continue
+			}
+		default:
+			ret = append(ret, tk)
+		}
+	}
+	return ret
+}
+
+func createDirectiveTokenGroups(tokens []*Token) ([]*Token, error) {
+	ret := make([]*Token, 0, len(tokens))
+	for i := 0; i < len(tokens); i++ {
+		tk := tokens[i]
+		switch tk.Type() {
+		case token.DirectiveType:
+			if i+1 >= len(tokens) {
+				return nil, errors.ErrSyntax("undefined directive value", tk.RawToken())
+			}
+			directiveName := &Token{
+				Group: &TokenGroup{
+					Type:   TokenGroupDirectiveName,
+					Tokens: []*Token{tk, tokens[i+1]},
+				},
+			}
+			i++
+			var valueTks []*Token
+			for j := i + 1; j < len(tokens); j++ {
+				if tokens[j].Line() != tk.Line() {
+					break
+				}
+				valueTks = append(valueTks, tokens[j])
+				i++
+			}
+			if i+1 >= len(tokens) || tokens[i+1].Type() != token.DocumentHeaderType {
+				return nil, errors.ErrSyntax("unexpected directive value. document not started", tk.RawToken())
+			}
+			if len(valueTks) != 0 {
+				ret = append(ret, &Token{
+					Group: &TokenGroup{
+						Type:   TokenGroupDirective,
+						Tokens: append([]*Token{directiveName}, valueTks...),
+					},
+				})
+			} else {
+				ret = append(ret, directiveName)
+			}
+		default:
+			ret = append(ret, tk)
+		}
+	}
+	return ret, nil
+}
+
+func createDocumentTokens(tokens []*Token) ([]*Token, error) {
+	var ret []*Token
+	for i := 0; i < len(tokens); i++ {
+		tk := tokens[i]
+		switch tk.Type() {
+		case token.DocumentHeaderType:
+			if i != 0 {
+				ret = append(ret, &Token{
+					Group: &TokenGroup{Tokens: tokens[:i]},
+				})
+			}
+			if i+1 == len(tokens) {
+				// if current token is last token, add DocumentHeader only tokens to ret.
+				return append(ret, &Token{
+					Group: &TokenGroup{
+						Type:   TokenGroupDocument,
+						Tokens: []*Token{tk},
+					},
+				}), nil
+			}
+			if tokens[i+1].Type() == token.DocumentHeaderType {
+				return append(ret, &Token{
+					Group: &TokenGroup{
+						Type:   TokenGroupDocument,
+						Tokens: []*Token{tk},
+					},
+				}), nil
+			}
+			if tokens[i].Line() == tokens[i+1].Line() {
+				switch tokens[i+1].GroupType() {
+				case TokenGroupMapKey, TokenGroupMapKeyValue:
+					return nil, errors.ErrSyntax("value cannot be placed after document separator", tokens[i+1].RawToken())
+				}
+				switch tokens[i+1].Type() {
+				case token.SequenceEntryType:
+					return nil, errors.ErrSyntax("value cannot be placed after document separator", tokens[i+1].RawToken())
+				}
+			}
+			tks, err := createDocumentTokens(tokens[i+1:])
+			if err != nil {
+				return nil, err
+			}
+			if len(tks) != 0 {
+				tks[0].SetGroupType(TokenGroupDocument)
+				tks[0].Group.Tokens = append([]*Token{tk}, tks[0].Group.Tokens...)
+				return append(ret, tks...), nil
+			}
+			return append(ret, &Token{
+				Group: &TokenGroup{
+					Type:   TokenGroupDocument,
+					Tokens: []*Token{tk},
+				},
+			}), nil
+		case token.DocumentEndType:
+			if i != 0 {
+				ret = append(ret, &Token{
+					Group: &TokenGroup{
+						Type:   TokenGroupDocument,
+						Tokens: tokens[0 : i+1],
+					},
+				})
+			}
+			if i+1 == len(tokens) {
+				return ret, nil
+			}
+			if isScalarType(tokens[i+1]) {
+				return nil, errors.ErrSyntax("unexpected end content", tokens[i+1].RawToken())
+			}
+
+			tks, err := createDocumentTokens(tokens[i+1:])
+			if err != nil {
+				return nil, err
+			}
+			return append(ret, tks...), nil
+		}
+	}
+	return append(ret, &Token{
+		Group: &TokenGroup{
+			Type:   TokenGroupDocument,
+			Tokens: tokens,
+		},
+	}), nil
+}
+
+func isScalarType(tk *Token) bool {
+	switch tk.GroupType() {
+	case TokenGroupMapKey, TokenGroupMapKeyValue:
+		return false
+	}
+	typ := tk.Type()
+	return typ == token.AnchorType ||
+		typ == token.AliasType ||
+		typ == token.LiteralType ||
+		typ == token.FoldedType ||
+		typ == token.NullType ||
+		typ == token.ImplicitNullType ||
+		typ == token.BoolType ||
+		typ == token.IntegerType ||
+		typ == token.BinaryIntegerType ||
+		typ == token.OctetIntegerType ||
+		typ == token.HexIntegerType ||
+		typ == token.FloatType ||
+		typ == token.InfinityType ||
+		typ == token.NanType ||
+		typ == token.StringType ||
+		typ == token.SingleQuoteType ||
+		typ == token.DoubleQuoteType
+}
+
+func isNotMapKeyType(tk *Token) bool {
+	typ := tk.Type()
+	return typ == token.DirectiveType ||
+		typ == token.DocumentHeaderType ||
+		typ == token.DocumentEndType ||
+		typ == token.CollectEntryType ||
+		typ == token.MappingStartType ||
+		typ == token.MappingValueType ||
+		typ == token.MappingEndType ||
+		typ == token.SequenceStartType ||
+		typ == token.SequenceEntryType ||
+		typ == token.SequenceEndType
+}
+
+func isFlowType(tk *Token) bool {
+	typ := tk.Type()
+	return typ == token.MappingStartType ||
+		typ == token.MappingEndType ||
+		typ == token.SequenceStartType ||
+		typ == token.SequenceEntryType
+}