Added XML decoder (#1044)

LICENSE

@@ -1,3 +1,5 @@
+The MIT License (MIT)
+
 Copyright (c) 2017 Mike Farah
 
 Permission is hereby granted, free of charge, to any person obtaining a copy

cmd/constant.go

@@ -6,6 +6,10 @@ var unwrapScalar = true
 var writeInplace = false
 var outputToJSON = false
 var outputFormat = "yaml"
+var inputFormat = "yaml"
+
+var xmlAttributePrefix = "+"
+var xmlContentName = "+content"
 
 var exitStatus = false
 var forceColor = false

cmd/evaluate_all_command.go

@@ -75,6 +75,11 @@ func evaluateAll(cmd *cobra.Command, args []string) error {
 		return err
 	}
 
+	decoder, err := configureDecoder()
+	if err != nil {
+		return err
+	}
+
 	printerWriter := configurePrinterWriter(format, out)
 
 	printer := yqlib.NewPrinter(printerWriter, format, unwrapScalar, colorsEnabled, indent, !noDocSeparators)
@@ -99,7 +104,7 @@ func evaluateAll(cmd *cobra.Command, args []string) error {
 	switch len(args) {
 	case 0:
 		if pipingStdIn {
-			err = allAtOnceEvaluator.EvaluateFiles(processExpression(""), []string{"-"}, printer, leadingContentPreProcessing)
+			err = allAtOnceEvaluator.EvaluateFiles(processExpression(""), []string{"-"}, printer, leadingContentPreProcessing, decoder)
 		} else {
 			cmd.Println(cmd.UsageString())
 			return nil
@@ -108,10 +113,10 @@ func evaluateAll(cmd *cobra.Command, args []string) error {
 		if nullInput {
 			err = yqlib.NewStreamEvaluator().EvaluateNew(processExpression(args[0]), printer, "")
 		} else {
-			err = allAtOnceEvaluator.EvaluateFiles(processExpression(""), []string{args[0]}, printer, leadingContentPreProcessing)
+			err = allAtOnceEvaluator.EvaluateFiles(processExpression(""), []string{args[0]}, printer, leadingContentPreProcessing, decoder)
 		}
 	default:
-		err = allAtOnceEvaluator.EvaluateFiles(processExpression(args[0]), args[1:], printer, leadingContentPreProcessing)
+		err = allAtOnceEvaluator.EvaluateFiles(processExpression(args[0]), args[1:], printer, leadingContentPreProcessing, decoder)
 	}
 
 	completedSuccessfully = err == nil

cmd/evalute_sequence_command.go

@@ -92,6 +92,11 @@ func evaluateSequence(cmd *cobra.Command, args []string) error {
 
 	printer := yqlib.NewPrinter(printerWriter, format, unwrapScalar, colorsEnabled, indent, !noDocSeparators)
 
+	decoder, err := configureDecoder()
+	if err != nil {
+		return err
+	}
+
 	streamEvaluator := yqlib.NewStreamEvaluator()
 
 	if frontMatter != "" {
@@ -113,7 +118,7 @@ func evaluateSequence(cmd *cobra.Command, args []string) error {
 	switch len(args) {
 	case 0:
 		if pipingStdIn {
-			err = streamEvaluator.EvaluateFiles(processExpression(""), []string{"-"}, printer, leadingContentPreProcessing)
+			err = streamEvaluator.EvaluateFiles(processExpression(""), []string{"-"}, printer, leadingContentPreProcessing, decoder)
 		} else {
 			cmd.Println(cmd.UsageString())
 			return nil
@@ -122,10 +127,10 @@ func evaluateSequence(cmd *cobra.Command, args []string) error {
 		if nullInput {
 			err = streamEvaluator.EvaluateNew(processExpression(args[0]), printer, "")
 		} else {
-			err = streamEvaluator.EvaluateFiles(processExpression(""), []string{args[0]}, printer, leadingContentPreProcessing)
+			err = streamEvaluator.EvaluateFiles(processExpression(""), []string{args[0]}, printer, leadingContentPreProcessing, decoder)
 		}
 	default:
-		err = streamEvaluator.EvaluateFiles(processExpression(args[0]), args[1:], printer, leadingContentPreProcessing)
+		err = streamEvaluator.EvaluateFiles(processExpression(args[0]), args[1:], printer, leadingContentPreProcessing, decoder)
 	}
 	completedSuccessfully = err == nil
 

cmd/root.go

@@ -49,6 +49,11 @@ See https://mikefarah.gitbook.io/yq/ for detailed documentation and examples.`,
 	}
 
 	rootCmd.PersistentFlags().StringVarP(&outputFormat, "output-format", "o", "yaml", "[yaml|y|json|j|props|p] output format type.")
+	rootCmd.PersistentFlags().StringVarP(&inputFormat, "input-format", "p", "yaml", "[yaml|y|xml|x] input format type.")
+
+	rootCmd.PersistentFlags().StringVar(&xmlAttributePrefix, "xml-attribute-prefix", "+", "prefix for xml attributes")
+	rootCmd.PersistentFlags().StringVar(&xmlContentName, "xml-content-name", "+content", "name for xml content (if no attribute name is present).")
+
 	rootCmd.PersistentFlags().BoolVarP(&nullInput, "null-input", "n", false, "Don't read input, simply evaluate the expression given. Useful for creating yaml docs from scratch.")
 	rootCmd.PersistentFlags().BoolVarP(&noDocSeparators, "no-doc", "N", false, "Don't print document separators (---)")
 

cmd/utils.go

@@ -45,6 +45,18 @@ func initCommand(cmd *cobra.Command, args []string) (firstFileIndex int, err err
 	return firstFileIndex, nil
 }
 
+func configureDecoder() (yqlib.Decoder, error) {
+	yqlibInputFormat, err := yqlib.InputFormatFromString(inputFormat)
+	if err != nil {
+		return nil, err
+	}
+	switch yqlibInputFormat {
+	case yqlib.XmlInputFormat:
+		return yqlib.NewXmlDecoder(xmlAttributePrefix, xmlContentName), nil
+	}
+	return yqlib.NewYamlDecoder(), nil
+}
+
 func configurePrinterWriter(format yqlib.PrinterOutputFormat, out io.Writer) yqlib.PrinterWriter {
 
 	var printerWriter yqlib.PrinterWriter

examples/mike.xml

@@ -0,0 +1,4 @@
+  <?xml version="1.0" encoding="UTF-8"?>
+  <cat>3f</cat>
+  <dog>meow:as</dog>
+  <dog3>true</dog3>

examples/mike2.xml

@@ -0,0 +1,11 @@
+  <?xml version="1.0" encoding="UTF-8"?>
+  <!-- osm-->
+  <osm version="0.6" generator="CGImap 0.0.2">
+  <!-- bounds-->
+   <bounds minlat="54.0889580" minlon="12.2487570" maxlat="54.0913900" maxlon="12.2524800">
+   <!-- great -->
+   cool
+   </bounds>
+   <foo>ba2234r</foo>
+   <foo>bar2234233</foo>
+  </osm>

go.mod

@@ -8,6 +8,7 @@ require (
 	github.com/magiconair/properties v1.8.5
 	github.com/spf13/cobra v1.3.0
 	github.com/timtadh/lexmachine v0.2.2
+	golang.org/x/net v0.0.0-20210813160813-60bc85c4be6d
 	gopkg.in/op/go-logging.v1 v1.0.0-20160211212156-b2cb9fa56473
 	gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b
 )
@@ -19,6 +20,7 @@ require (
 	github.com/spf13/pflag v1.0.5 // indirect
 	github.com/timtadh/data-structures v0.5.3 // indirect
 	golang.org/x/sys v0.0.0-20211205182925-97ca703d548d // indirect
+	golang.org/x/text v0.3.7 // indirect
 	golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 // indirect
 )
 

go.sum

@@ -449,6 +449,7 @@ golang.org/x/net v0.0.0-20210316092652-d523dce5a7f4/go.mod h1:RBQZq4jEuRlivfhVLd
 golang.org/x/net v0.0.0-20210405180319-a5a99cb37ef4/go.mod h1:p54w0d4576C0XHj96bSt6lcn1PtDYWL6XObtHCRCNQM=
 golang.org/x/net v0.0.0-20210410081132-afb366fc7cd1/go.mod h1:9tjilg8BloeKEkVJvy7fQ90B1CfIiPueXVOjqfkSzI8=
 golang.org/x/net v0.0.0-20210503060351-7fd8e65b6420/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
+golang.org/x/net v0.0.0-20210813160813-60bc85c4be6d h1:LO7XpTYMwTqxjLcGWPijK3vRXg1aWdlNOVOHRq45d7c=
 golang.org/x/net v0.0.0-20210813160813-60bc85c4be6d/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/oauth2 v0.0.0-20190226205417-e64efc72b421/go.mod h1:gOpvHmFTYa4IltrdGE7lF6nIHvwfUNPOp7c8zoXwtLw=
@@ -553,6 +554,7 @@ golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/text v0.3.4/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/text v0.3.5/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
+golang.org/x/text v0.3.7 h1:olpwvP2KacW1ZWvsR7uQhoyTYvKAupfQrRGBFM352Gk=
 golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
 golang.org/x/time v0.0.0-20181108054448-85acf8d2951c/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
 golang.org/x/time v0.0.0-20190308202827-9d24e82272b4/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=

pkg/yqlib/all_at_once_evaluator.go

@@ -8,7 +8,7 @@ import (
 
 // A yaml expression evaluator that runs the expression once against all files/nodes in memory.
 type Evaluator interface {
-	EvaluateFiles(expression string, filenames []string, printer Printer, leadingContentPreProcessing bool) error
+	EvaluateFiles(expression string, filenames []string, printer Printer, leadingContentPreProcessing bool, decoder Decoder) error
 
 	// EvaluateNodes takes an expression and one or more yaml nodes, returning a list of matching candidate nodes
 	EvaluateNodes(expression string, nodes ...*yaml.Node) (*list.List, error)
@@ -46,7 +46,7 @@ func (e *allAtOnceEvaluator) EvaluateCandidateNodes(expression string, inputCand
 	return context.MatchingNodes, nil
 }
 
-func (e *allAtOnceEvaluator) EvaluateFiles(expression string, filenames []string, printer Printer, leadingContentPreProcessing bool) error {
+func (e *allAtOnceEvaluator) EvaluateFiles(expression string, filenames []string, printer Printer, leadingContentPreProcessing bool, decoder Decoder) error {
 	fileIndex := 0
 	firstFileLeadingContent := ""
 
@@ -61,7 +61,7 @@ func (e *allAtOnceEvaluator) EvaluateFiles(expression string, filenames []string
 			firstFileLeadingContent = leadingContent
 		}
 
-		fileDocuments, err := readDocuments(reader, filename, fileIndex)
+		fileDocuments, err := readDocuments(reader, filename, fileIndex, decoder)
 		if err != nil {
 			return err
 		}

pkg/yqlib/decode_xml_test.go

@@ -0,0 +1,110 @@
+package yqlib
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"strings"
+	"testing"
+
+	"github.com/mikefarah/yq/v4/test"
+	yaml "gopkg.in/yaml.v3"
+)
+
+func decodeXml(t *testing.T, xml string) *CandidateNode {
+	decoder := NewXmlDecoder("+", "+content")
+
+	decoder.Init(strings.NewReader(xml))
+
+	node := &yaml.Node{}
+	err := decoder.Decode(node)
+	if err != nil {
+		t.Error(err, "fail to decode", xml)
+	}
+	return &CandidateNode{Node: node}
+}
+
+type xmlScenario struct {
+	inputXml       string
+	expected       string
+	description    string
+	subdescription string
+	skipDoc        bool
+}
+
+var xmlScenarios = []xmlScenario{
+	{
+		description: "Parse xml: simple",
+		inputXml:    "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<cat>meow</cat>",
+		expected:    "D0, P[], (doc)::cat: meow\n",
+	},
+	{
+		description:    "Parse xml: array",
+		subdescription: "Consecutive nodes with identical xml names are assumed to be arrays.",
+		inputXml:       "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<animal>1</animal>\n<animal>2</animal>",
+		expected:       "D0, P[], (doc)::animal:\n    - \"1\"\n    - \"2\"\n",
+	},
+	{
+		description:    "Parse xml: attributes",
+		subdescription: "Attributes are converted to fields, with the attribute prefix.",
+		inputXml:       "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<cat legs=\"4\">\n  <legs>7</legs>\n</cat>",
+		expected:       "D0, P[], (doc)::cat:\n    +legs: \"4\"\n    legs: \"7\"\n",
+	},
+	{
+		description:    "Parse xml: attributes with content",
+		subdescription: "Content is added as a field, using the content name",
+		inputXml:       "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<cat legs=\"4\">meow</cat>",
+		expected:       "D0, P[], (doc)::cat:\n    +content: meow\n    +legs: \"4\"\n",
+	},
+}
+
+func testXmlScenario(t *testing.T, s *xmlScenario) {
+	var actual = resultToString(t, decodeXml(t, s.inputXml))
+	test.AssertResult(t, s.expected, actual)
+}
+
+func documentXmlScenario(t *testing.T, w *bufio.Writer, i interface{}) {
+	s := i.(xmlScenario)
+
+	if s.skipDoc {
+		return
+	}
+	writeOrPanic(w, fmt.Sprintf("## %v\n", s.description))
+
+	if s.subdescription != "" {
+		writeOrPanic(w, s.subdescription)
+		writeOrPanic(w, "\n\n")
+	}
+
+	writeOrPanic(w, "Given a sample.xml file of:\n")
+	writeOrPanic(w, fmt.Sprintf("```xml\n%v\n```\n", s.inputXml))
+
+	writeOrPanic(w, "then\n")
+	writeOrPanic(w, "```bash\nyq e sample.xml\n```\n")
+	writeOrPanic(w, "will output\n")
+
+	var output bytes.Buffer
+	printer := NewPrinterWithSingleWriter(bufio.NewWriter(&output), YamlOutputFormat, true, false, 2, true)
+
+	node := decodeXml(t, s.inputXml)
+
+	err := printer.PrintResults(node.AsList())
+	if err != nil {
+		t.Error(err)
+		return
+	}
+
+	writeOrPanic(w, fmt.Sprintf("```yaml\n%v```\n\n", output.String()))
+
+}
+
+func TestXmlScenarios(t *testing.T) {
+	for _, tt := range xmlScenarios {
+		testXmlScenario(t, &tt)
+	}
+	genericScenarios := make([]interface{}, len(xmlScenarios))
+	for i, s := range xmlScenarios {
+		genericScenarios[i] = s
+	}
+	documentScenarios(t, "usage", "xml", genericScenarios, documentXmlScenario)
+}

pkg/yqlib/decoder_xml.go

@@ -0,0 +1,249 @@
+package yqlib
+
+import (
+	"encoding/xml"
+	"fmt"
+	"io"
+	"unicode"
+
+	"golang.org/x/net/html/charset"
+	yaml "gopkg.in/yaml.v3"
+)
+
+type InputFormat uint
+
+const (
+	YamlInputFormat = 1 << iota
+	XmlInputFormat
+)
+
+func InputFormatFromString(format string) (InputFormat, error) {
+	switch format {
+	case "yaml", "y":
+		return YamlInputFormat, nil
+	case "xml", "x":
+		return XmlInputFormat, nil
+	default:
+		return 0, fmt.Errorf("unknown format '%v' please use [yaml|xml]", format)
+	}
+}
+
+type xmlDecoder struct {
+	reader          io.Reader
+	attributePrefix string
+	contentPrefix   string
+	finished        bool
+}
+
+func NewXmlDecoder(attributePrefix string, contentPrefix string) Decoder {
+	if contentPrefix == "" {
+		contentPrefix = "content"
+	}
+	return &xmlDecoder{attributePrefix: attributePrefix, contentPrefix: contentPrefix, finished: false}
+}
+
+func (dec *xmlDecoder) Init(reader io.Reader) {
+	dec.reader = reader
+	dec.finished = false
+}
+
+func (dec *xmlDecoder) createSequence(nodes []*xmlNode) (*yaml.Node, error) {
+	yamlNode := &yaml.Node{Kind: yaml.SequenceNode}
+	for _, child := range nodes {
+		yamlChild, err := dec.convertToYamlNode(child)
+		if err != nil {
+			return nil, err
+		}
+		yamlNode.Content = append(yamlNode.Content, yamlChild)
+	}
+
+	return yamlNode, nil
+}
+
+func (dec *xmlDecoder) createMap(n *xmlNode) (*yaml.Node, error) {
+	yamlNode := &yaml.Node{Kind: yaml.MappingNode, HeadComment: n.Comment}
+
+	if len(n.Data) > 0 {
+		label := dec.contentPrefix
+		yamlNode.Content = append(yamlNode.Content, createScalarNode(label, label), createScalarNode(n.Data, n.Data))
+	}
+
+	for _, keyValuePair := range n.Children {
+		label := keyValuePair.K
+		children := keyValuePair.V
+		labelNode := createScalarNode(label, label)
+		var valueNode *yaml.Node
+		var err error
+		log.Debug("len of children in %v is %v", label, len(children))
+		if len(children) > 1 {
+			valueNode, err = dec.createSequence(children)
+			if err != nil {
+				return nil, err
+			}
+		} else {
+			valueNode, err = dec.convertToYamlNode(children[0])
+			if err != nil {
+				return nil, err
+			}
+		}
+		yamlNode.Content = append(yamlNode.Content, labelNode, valueNode)
+	}
+
+	return yamlNode, nil
+}
+
+func (dec *xmlDecoder) convertToYamlNode(n *xmlNode) (*yaml.Node, error) {
+	if len(n.Children) > 0 {
+		return dec.createMap(n)
+	}
+	scalar := createScalarNode(n.Data, n.Data)
+	scalar.HeadComment = n.Comment
+	return scalar, nil
+}
+
+func (dec *xmlDecoder) Decode(rootYamlNode *yaml.Node) error {
+	if dec.finished {
+		return io.EOF
+	}
+	root := &xmlNode{}
+	// cant use xj - it doesn't keep map order.
+	err := dec.decodeXml(root)
+
+	if err != nil {
+		return err
+	}
+	firstNode, err := dec.convertToYamlNode(root)
+
+	if err != nil {
+		return err
+	}
+	rootYamlNode.Kind = yaml.DocumentNode
+	rootYamlNode.Content = []*yaml.Node{firstNode}
+	dec.finished = true
+	return nil
+}
+
+type xmlNode struct {
+	Children []*xmlChildrenKv
+	Comment  string
+	Data     string
+}
+
+type xmlChildrenKv struct {
+	K string
+	V []*xmlNode
+}
+
+// AddChild appends a node to the list of children
+func (n *xmlNode) AddChild(s string, c *xmlNode) {
+
+	if n.Children == nil {
+		n.Children = make([]*xmlChildrenKv, 0)
+	}
+	log.Debug("looking for %s", s)
+	// see if we can find an existing entry to add to
+	for _, childEntry := range n.Children {
+		if childEntry.K == s {
+			log.Debug("found it, appending an entry%s", s)
+			childEntry.V = append(childEntry.V, c)
+			log.Debug("yay len of children in %v is %v", s, len(childEntry.V))
+			return
+		}
+	}
+	log.Debug("not there, making a new one %s", s)
+	n.Children = append(n.Children, &xmlChildrenKv{K: s, V: []*xmlNode{c}})
+}
+
+type element struct {
+	parent *element
+	n      *xmlNode
+	label  string
+}
+
+// this code is heavily based on https://github.com/basgys/goxml2json
+// main changes are to decode into a structure that preserves the original order
+// of the map keys.
+func (dec *xmlDecoder) decodeXml(root *xmlNode) error {
+	xmlDec := xml.NewDecoder(dec.reader)
+
+	// That will convert the charset if the provided XML is non-UTF-8
+	xmlDec.CharsetReader = charset.NewReaderLabel
+
+	// Create first element from the root node
+	elem := &element{
+		parent: nil,
+		n:      root,
+	}
+
+	for {
+		t, _ := xmlDec.Token()
+		if t == nil {
+			break
+		}
+
+		switch se := t.(type) {
+		case xml.StartElement:
+			// Build new a new current element and link it to its parent
+			elem = &element{
+				parent: elem,
+				n:      &xmlNode{},
+				label:  se.Name.Local,
+			}
+
+			// Extract attributes as children
+			for _, a := range se.Attr {
+				elem.n.AddChild(dec.attributePrefix+a.Name.Local, &xmlNode{Data: a.Value})
+			}
+		case xml.CharData:
+			// Extract XML data (if any)
+			elem.n.Data = trimNonGraphic(string(se))
+		case xml.EndElement:
+			// And add it to its parent list
+			if elem.parent != nil {
+				elem.parent.n.AddChild(elem.label, elem.n)
+			}
+
+			// Then change the current element to its parent
+			elem = elem.parent
+		case xml.Comment:
+			elem.n.Comment = trimNonGraphic(string(xml.CharData(se)))
+		}
+	}
+
+	return nil
+}
+
+// trimNonGraphic returns a slice of the string s, with all leading and trailing
+// non graphic characters and spaces removed.
+//
+// Graphic characters include letters, marks, numbers, punctuation, symbols,
+// and spaces, from categories L, M, N, P, S, Zs.
+// Spacing characters are set by category Z and property Pattern_White_Space.
+func trimNonGraphic(s string) string {
+	if s == "" {
+		return s
+	}
+
+	var first *int
+	var last int
+	for i, r := range []rune(s) {
+		if !unicode.IsGraphic(r) || unicode.IsSpace(r) {
+			continue
+		}
+
+		if first == nil {
+			f := i // copy i
+			first = &f
+			last = i
+		} else {
+			last = i
+		}
+	}
+
+	// If first is nil, it means there are no graphic characters
+	if first == nil {
+		return ""
+	}
+
+	return string([]rune(s)[*first : last+1])
+}

pkg/yqlib/decoder_yaml.go

@@ -0,0 +1,28 @@
+package yqlib
+
+import (
+	"io"
+
+	yaml "gopkg.in/yaml.v3"
+)
+
+type Decoder interface {
+	Init(reader io.Reader)
+	Decode(node *yaml.Node) error
+}
+
+type yamlDecoder struct {
+	decoder yaml.Decoder
+}
+
+func NewYamlDecoder() Decoder {
+	return &yamlDecoder{}
+}
+
+func (dec *yamlDecoder) Init(reader io.Reader) {
+	dec.decoder = *yaml.NewDecoder(reader)
+}
+
+func (dec *yamlDecoder) Decode(rootYamlNode *yaml.Node) error {
+	return dec.decoder.Decode(rootYamlNode)
+}

pkg/yqlib/doc/operators/encode-decode.md

@@ -271,3 +271,19 @@ cat	thing1,thing2	true	3.40
 dog	thing3	false	12
 ```
 
+## Decode a xml encoded string
+Given a sample.yml file of:
+```yaml
+a: <foo>bar</foo>
+```
+then
+```bash
+yq eval '.b = (.a | from_xml)' sample.yml
+```
+will output
+```yaml
+a: <foo>bar</foo>
+b:
+  foo: bar
+```
+

pkg/yqlib/doc/operators/headers/encode-decode.md

@@ -14,6 +14,7 @@ These operators are useful to process yaml documents that have stringified embed
 | Properties |  | to_props/@props |
 | CSV |  | to_csv/@csv |
 | TSV |  | to_tsv/@tsv |
+| XML | from_xml |  |
 
 
 CSV and TSV format both accept either a single array or scalars (representing a single row), or an array of array of scalars (representing multiple rows). 

pkg/yqlib/doc/usage/headers/xml.md

@@ -0,0 +1,12 @@
+# XML
+
+At the moment, `yq` only supports decoding `xml` (into one of the other supported output formats).
+
+As yaml does not have the concept of attributes, these are converted to regular fields with a prefix to prevent clobbering. Consecutive xml nodes with the same name are assumed to be arrays.
+
+All values in XML are assumed to be strings - but you can use `from_yaml` to parse them into their correct types:
+
+
+```
+yq e -p=xml '.myNumberField |= from_yaml' my.xml
+```