Added "debug-node-info" flag for inspecting yq AST

cmd/constant.go

@@ -2,6 +2,8 @@ package cmd
 
 var unwrapScalarFlag = newUnwrapFlag()
 
+var printNodeInfo = false
+
 var unwrapScalar = false
 
 var writeInplace = false

cmd/evaluate_sequence_command.go

@@ -105,6 +105,11 @@ func evaluateSequence(cmd *cobra.Command, args []string) (cmdError error) {
 	}
 
 	printer := yqlib.NewPrinter(encoder, printerWriter)
+
+	if printNodeInfo {
+		printer = yqlib.NewNodeInfoPrinter(printerWriter)
+	}
+
 	if nulSepOutput {
 		printer.SetNulSepOutput(true)
 	}

cmd/root.go

@@ -99,6 +99,7 @@ yq -P -oy sample.json
 	}
 
 	rootCmd.PersistentFlags().BoolVarP(&verbose, "verbose", "v", false, "verbose mode")
+	rootCmd.PersistentFlags().BoolVarP(&printNodeInfo, "debug-node-info", "", false, "debug node info")
 
 	rootCmd.PersistentFlags().BoolVarP(&outputToJSON, "tojson", "j", false, "(deprecated) output as json. Set indent to 0 to print json in one line.")
 	err := rootCmd.PersistentFlags().MarkDeprecated("tojson", "please use -o=json instead")

examples/data1.yaml

@@ -1,3 +1,8 @@
-Foo: 3
-apple: 1
-bar: 2
+# 001
+---
+abc:  # 001
+- 1   # one
+- 2   # two
+
+---
+def   # 002

pkg/yqlib/candidate_node.go

@@ -53,6 +53,20 @@ func createScalarNode(value interface{}, stringValue string) *CandidateNode {
 	return node
 }
 
+type NodeInfo struct {
+	Kind        string      `yaml:"kind"`
+	Style       string      `yaml:"style,omitempty"`
+	Anchor      string      `yaml:"anchor,omitempty"`
+	Tag         string      `yaml:"tag,omitempty"`
+	HeadComment string      `yaml:"headComment,omitempty"`
+	LineComment string      `yaml:"lineComment,omitempty"`
+	FootComment string      `yaml:"footComment,omitempty"`
+	Value       string      `yaml:"value,omitempty"`
+	Line        int         `yaml:"line,omitempty"`
+	Column      int         `yaml:"column,omitempty"`
+	Content     []*NodeInfo `yaml:"content,omitempty"`
+}
+
 type CandidateNode struct {
 	Kind  Kind
 	Style Style
@@ -451,3 +465,64 @@ func (n *CandidateNode) UpdateAttributesFrom(other *CandidateNode, prefs assignP
 		n.LineComment = other.LineComment
 	}
 }
+
+func (n *CandidateNode) ConvertToNodeInfo() *NodeInfo {
+	info := &NodeInfo{
+		Kind:        kindToString(n.Kind),
+		Style:       styleToString(n.Style),
+		Anchor:      n.Anchor,
+		Tag:         n.Tag,
+		HeadComment: n.HeadComment,
+		LineComment: n.LineComment,
+		FootComment: n.FootComment,
+		Value:       n.Value,
+		Line:        n.Line,
+		Column:      n.Column,
+	}
+	if len(n.Content) > 0 {
+		info.Content = make([]*NodeInfo, len(n.Content))
+		for i, child := range n.Content {
+			info.Content[i] = child.ConvertToNodeInfo()
+		}
+	}
+	return info
+}
+
+// Helper functions to convert Kind and Style to string for NodeInfo
+func kindToString(k Kind) string {
+	switch k {
+	case SequenceNode:
+		return "SequenceNode"
+	case MappingNode:
+		return "MappingNode"
+	case ScalarNode:
+		return "ScalarNode"
+	case AliasNode:
+		return "AliasNode"
+	default:
+		return "Unknown"
+	}
+}
+
+func styleToString(s Style) string {
+	var styles []string
+	if s&TaggedStyle != 0 {
+		styles = append(styles, "TaggedStyle")
+	}
+	if s&DoubleQuotedStyle != 0 {
+		styles = append(styles, "DoubleQuotedStyle")
+	}
+	if s&SingleQuotedStyle != 0 {
+		styles = append(styles, "SingleQuotedStyle")
+	}
+	if s&LiteralStyle != 0 {
+		styles = append(styles, "LiteralStyle")
+	}
+	if s&FoldedStyle != 0 {
+		styles = append(styles, "FoldedStyle")
+	}
+	if s&FlowStyle != 0 {
+		styles = append(styles, "FlowStyle")
+	}
+	return strings.Join(styles, ",")
+}

pkg/yqlib/candidate_node_test.go

@@ -160,3 +160,47 @@ func TestCandidateNodeAddKeyValueChild(t *testing.T) {
 	test.AssertResult(t, key.IsMapKey, true)
 
 }
+
+func TestConvertToNodeInfo(t *testing.T) {
+	child := &CandidateNode{
+		Kind:   ScalarNode,
+		Style:  DoubleQuotedStyle,
+		Tag:    "!!str",
+		Value:  "childValue",
+		Line:   2,
+		Column: 3,
+	}
+	parent := &CandidateNode{
+		Kind:        MappingNode,
+		Style:       TaggedStyle,
+		Tag:         "!!map",
+		Value:       "",
+		Line:        1,
+		Column:      1,
+		Content:     []*CandidateNode{child},
+		HeadComment: "head",
+		LineComment: "line",
+		FootComment: "foot",
+		Anchor:      "anchor",
+	}
+	info := parent.ConvertToNodeInfo()
+	test.AssertResult(t, "MappingNode", info.Kind)
+	test.AssertResult(t, "TaggedStyle", info.Style)
+	test.AssertResult(t, "!!map", info.Tag)
+	test.AssertResult(t, "head", info.HeadComment)
+	test.AssertResult(t, "line", info.LineComment)
+	test.AssertResult(t, "foot", info.FootComment)
+	test.AssertResult(t, "anchor", info.Anchor)
+	test.AssertResult(t, 1, info.Line)
+	test.AssertResult(t, 1, info.Column)
+	if len(info.Content) != 1 {
+		t.Fatalf("Expected 1 child, got %d", len(info.Content))
+	}
+	childInfo := info.Content[0]
+	test.AssertResult(t, "ScalarNode", childInfo.Kind)
+	test.AssertResult(t, "DoubleQuotedStyle", childInfo.Style)
+	test.AssertResult(t, "!!str", childInfo.Tag)
+	test.AssertResult(t, "childValue", childInfo.Value)
+	test.AssertResult(t, 2, childInfo.Line)
+	test.AssertResult(t, 3, childInfo.Column)
+}

pkg/yqlib/printer_node_info.go

@@ -0,0 +1,76 @@
+package yqlib
+
+import (
+	"bufio"
+	"container/list"
+	"io"
+
+	"go.yaml.in/yaml/v3"
+)
+
+type nodeInfoPrinter struct {
+	printerWriter  PrinterWriter
+	appendixReader io.Reader
+	printedMatches bool
+}
+
+func NewNodeInfoPrinter(printerWriter PrinterWriter) Printer {
+	return &nodeInfoPrinter{
+		printerWriter: printerWriter,
+	}
+}
+
+func (p *nodeInfoPrinter) SetNulSepOutput(_ bool) {
+}
+
+func (p *nodeInfoPrinter) SetAppendix(reader io.Reader) {
+	p.appendixReader = reader
+}
+
+func (p *nodeInfoPrinter) PrintedAnything() bool {
+	return p.printedMatches
+}
+
+func (p *nodeInfoPrinter) PrintResults(matchingNodes *list.List) error {
+
+	for el := matchingNodes.Front(); el != nil; el = el.Next() {
+		mappedDoc := el.Value.(*CandidateNode)
+		writer, errorWriting := p.printerWriter.GetWriter(mappedDoc)
+		if errorWriting != nil {
+			return errorWriting
+		}
+		bytes, err := yaml.Marshal(mappedDoc.ConvertToNodeInfo())
+		if err != nil {
+			return err
+		}
+		if _, err := writer.Write(bytes); err != nil {
+			return err
+		}
+		if _, err := writer.Write([]byte("\n")); err != nil {
+			return err
+		}
+		p.printedMatches = true
+		if err := writer.Flush(); err != nil {
+			return err
+		}
+	}
+
+	if p.appendixReader != nil {
+		writer, err := p.printerWriter.GetWriter(nil)
+		if err != nil {
+			return err
+		}
+
+		log.Debug("Piping appendix reader...")
+		betterReader := bufio.NewReader(p.appendixReader)
+		_, err = io.Copy(writer, betterReader)
+		if err != nil {
+			return err
+		}
+		if err := writer.Flush(); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}

pkg/yqlib/printer_node_info_test.go

@@ -0,0 +1,51 @@
+package yqlib
+
+import (
+	"bufio"
+	"bytes"
+	"container/list"
+	"strings"
+	"testing"
+
+	"github.com/mikefarah/yq/v4/test"
+)
+
+func TestNodeInfoPrinter_PrintResults(t *testing.T) {
+	// Create a simple CandidateNode
+	node := &CandidateNode{
+		Kind:        ScalarNode,
+		Style:       DoubleQuotedStyle,
+		Tag:         "!!str",
+		Value:       "hello world",
+		Line:        5,
+		Column:      7,
+		HeadComment: "head",
+		LineComment: "line",
+		FootComment: "foot",
+		Anchor:      "anchor",
+	}
+	listNodes := list.New()
+	listNodes.PushBack(node)
+
+	var output bytes.Buffer
+	writer := bufio.NewWriter(&output)
+	printer := NewNodeInfoPrinter(NewSinglePrinterWriter(writer))
+	err := printer.PrintResults(listNodes)
+	writer.Flush()
+	if err != nil {
+		t.Fatalf("PrintResults error: %v", err)
+	}
+
+	outStr := output.String()
+	// Check for key NodeInfo fields in YAML output using substring checks
+	test.AssertResult(t, true, strings.Contains(outStr, "kind: ScalarNode"))
+	test.AssertResult(t, true, strings.Contains(outStr, "style: DoubleQuotedStyle"))
+	test.AssertResult(t, true, strings.Contains(outStr, "tag: '!!str'"))
+	test.AssertResult(t, true, strings.Contains(outStr, "value: hello world"))
+	test.AssertResult(t, true, strings.Contains(outStr, "line: 5"))
+	test.AssertResult(t, true, strings.Contains(outStr, "column: 7"))
+	test.AssertResult(t, true, strings.Contains(outStr, "headComment: head"))
+	test.AssertResult(t, true, strings.Contains(outStr, "lineComment: line"))
+	test.AssertResult(t, true, strings.Contains(outStr, "footComment: foot"))
+	test.AssertResult(t, true, strings.Contains(outStr, "anchor: anchor"))
+}