Merge 02b28073bf into 4532346e13

go.mod

@@ -17,7 +17,7 @@ require (
 	github.com/spf13/cobra v1.10.1
 	github.com/spf13/pflag v1.0.10
 	github.com/yuin/gopher-lua v1.1.1
-	go.yaml.in/yaml/v3 v3.0.4
+	go.yaml.in/yaml/v4 v4.0.0-rc.2
 	golang.org/x/net v0.43.0
 	golang.org/x/text v0.28.0
 	gopkg.in/op/go-logging.v1 v1.0.0-20160211212156-b2cb9fa56473

go.sum

@@ -50,8 +50,8 @@ github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5Cc
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/yuin/gopher-lua v1.1.1 h1:kYKnWBjvbNP4XLT3+bPEwAXJx262OhaHDWDVOPjL46M=
 github.com/yuin/gopher-lua v1.1.1/go.mod h1:GBR0iDaNXjAgGg9zfCvksxSRnQx76gclCIb7kdAd1Pw=
-go.yaml.in/yaml/v3 v3.0.4 h1:tfq32ie2Jv2UxXFdLJdh3jXuOzWiL1fo0bu/FbuKpbc=
-go.yaml.in/yaml/v3 v3.0.4/go.mod h1:DhzuOOF2ATzADvBadXxruRBLzYTpT36CKvDb3+aBEFg=
+go.yaml.in/yaml/v4 v4.0.0-rc.2 h1:/FrI8D64VSr4HtGIlUtlFMGsm7H7pWTbj6vOLVZcA6s=
+go.yaml.in/yaml/v4 v4.0.0-rc.2/go.mod h1:aZqd9kCMsGL7AuUv/m/PvWLdg5sjJsZ4oHDEnfPPfY0=
 golang.org/x/net v0.43.0 h1:lat02VYK2j4aLzMzecihNvTlJNQUq316m2Mr9rnM6YE=
 golang.org/x/net v0.43.0/go.mod h1:vhO1fvI4dGsIjh73sWfUVjj3N7CA9WkKJNQm2svM6Jg=
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
@@ -59,7 +59,6 @@ golang.org/x/sys v0.35.0 h1:vz1N37gP5bs89s7He8XuIYXpyY0+QlsKmzipCbUtyxI=
 golang.org/x/sys v0.35.0/go.mod h1:BJP2sWEmIv4KK5OTEluFJCKSidICx8ciO85XgH3Ak8k=
 golang.org/x/text v0.28.0 h1:rhazDwis8INMIwQ4tpjLDzUhx6RlXqZNPEM0huQojng=
 golang.org/x/text v0.28.0/go.mod h1:U8nCwOR8jO/marOQ0QbDiOngZVEBB7MAiitBuMjXiNU=
-gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/op/go-logging.v1 v1.0.0-20160211212156-b2cb9fa56473 h1:6D+BvnJ/j6e222UW8s2qTSe3wGBtvo0MbVQG/c5k8RE=
 gopkg.in/op/go-logging.v1 v1.0.0-20160211212156-b2cb9fa56473/go.mod h1:N1eN2tsCx0Ydtgjl4cqmbRCsY4/+z4cYDeqwZTk6zog=

pkg/yqlib/candidate_node_yaml.go

@@ -3,7 +3,7 @@ package yqlib
 import (
 	"fmt"
 
-	yaml "go.yaml.in/yaml/v3"
+	yaml "go.yaml.in/yaml/v4"
 )
 
 func MapYamlStyle(original yaml.Style) Style {

pkg/yqlib/decoder_yaml.go

@@ -8,7 +8,7 @@ import (
 	"regexp"
 	"strings"
 
-	yaml "go.yaml.in/yaml/v3"
+	yaml "go.yaml.in/yaml/v4"
 )
 
 type yamlDecoder struct {

pkg/yqlib/doc/operators/anchor-and-alias-operators.md

@@ -198,12 +198,6 @@ then
 yq 'explode(.f)' sample.yml
 ```
 will output
-```yaml
-f:
-  a: cat
-  cat: b
-```
-
 ## Dereference and update a field
 Use explode with multiply to dereference an object
 
@@ -345,139 +339,3 @@ x: 1
 y: 2
 ```
 
-## FIXED: Explode with merge anchors
-Set `--yaml-fix-merge-anchor-to-spec=true` to get this correct merge behaviour (flag will default to true in late 2025).
-Observe that foobarList.b property is still foobarList_b.
-
-Given a sample.yml file of:
-```yaml
-foo: &foo
-  a: foo_a
-  thing: foo_thing
-  c: foo_c
-bar: &bar
-  b: bar_b
-  thing: bar_thing
-  c: bar_c
-foobarList:
-  b: foobarList_b
-  !!merge <<:
-    - *foo
-    - *bar
-  c: foobarList_c
-foobar:
-  c: foobar_c
-  !!merge <<: *foo
-  thing: foobar_thing
-```
-then
-```bash
-yq 'explode(.)' sample.yml
-```
-will output
-```yaml
-foo:
-  a: foo_a
-  thing: foo_thing
-  c: foo_c
-bar:
-  b: bar_b
-  thing: bar_thing
-  c: bar_c
-foobarList:
-  b: foobarList_b
-  a: foo_a
-  thing: foo_thing
-  c: foobarList_c
-foobar:
-  c: foobar_c
-  a: foo_a
-  thing: foobar_thing
-```
-
-## FIXED: Merge multiple maps
-Set `--yaml-fix-merge-anchor-to-spec=true` to get this correct merge behaviour (flag will default to true in late 2025).
-Taken from https://yaml.org/type/merge.html. Same values as legacy, but with the correct key order.
-
-Given a sample.yml file of:
-```yaml
-- &CENTER
-  x: 1
-  y: 2
-- &LEFT
-  x: 0
-  y: 2
-- &BIG
-  r: 10
-- &SMALL
-  r: 1
-- !!merge <<:
-    - *CENTER
-    - *BIG
-```
-then
-```bash
-yq '.[4] | explode(.)' sample.yml
-```
-will output
-```yaml
-x: 1
-y: 2
-r: 10
-```
-
-## FIXED: Override
-Set `--yaml-fix-merge-anchor-to-spec=true` to get this correct merge behaviour (flag will default to true in late 2025).
-Taken from https://yaml.org/type/merge.html. Same values as legacy, but with the correct key order.
-
-Given a sample.yml file of:
-```yaml
-- &CENTER
-  x: 1
-  y: 2
-- &LEFT
-  x: 0
-  y: 2
-- &BIG
-  r: 10
-- &SMALL
-  r: 1
-- !!merge <<:
-    - *BIG
-    - *LEFT
-    - *SMALL
-  x: 1
-```
-then
-```bash
-yq '.[4] | explode(.)' sample.yml
-```
-will output
-```yaml
-r: 10
-y: 2
-x: 1
-```
-
-## Exploding inline merge anchor
-Set `--yaml-fix-merge-anchor-to-spec=true` to get this correct merge behaviour (flag will default to true in late 2025).
-
-
-Given a sample.yml file of:
-```yaml
-a:
-  b: &b 42
-!!merge <<:
-  c: *b
-```
-then
-```bash
-yq 'explode(.) | sort_keys(.)' sample.yml
-```
-will output
-```yaml
-a:
-  b: 42
-c: 42
-```
-

pkg/yqlib/doc/operators/first.md

@@ -0,0 +1,345 @@
+
+## First matching element from array
+Given a sample.yml file of:
+```yaml
+- a: banana
+- a: cat
+- a: apple
+```
+then
+```bash
+yq 'first(.a == "cat")' sample.yml
+```
+will output
+```yaml
+a: cat
+```
+
+## First matching element from array with multiple matches
+Given a sample.yml file of:
+```yaml
+- a: banana
+- a: cat
+- a: apple
+- a: cat
+```
+then
+```bash
+yq 'first(.a == "cat")' sample.yml
+```
+will output
+```yaml
+a: cat
+```
+
+## First matching element from array with numeric condition
+Given a sample.yml file of:
+```yaml
+- a: 10
+- a: 100
+- a: 1
+```
+then
+```bash
+yq 'first(.a > 50)' sample.yml
+```
+will output
+```yaml
+a: 100
+```
+
+## First matching element from array with boolean condition
+Given a sample.yml file of:
+```yaml
+- a: false
+- a: true
+- a: false
+```
+then
+```bash
+yq 'first(.a == true)' sample.yml
+```
+will output
+```yaml
+a: true
+```
+
+## First matching element from array with null values
+Given a sample.yml file of:
+```yaml
+- a: null
+- a: cat
+- a: apple
+```
+then
+```bash
+yq 'first(.a != null)' sample.yml
+```
+will output
+```yaml
+a: cat
+```
+
+## First matching element from array with complex condition
+Given a sample.yml file of:
+```yaml
+- a: dog
+  b: 5
+- a: cat
+  b: 3
+- a: apple
+  b: 7
+```
+then
+```bash
+yq 'first(.b > 4)' sample.yml
+```
+will output
+```yaml
+a: dog
+b: 5
+```
+
+## First matching element from map
+Given a sample.yml file of:
+```yaml
+x:
+  a: banana
+y:
+  a: cat
+z:
+  a: apple
+```
+then
+```bash
+yq 'first(.a == "cat")' sample.yml
+```
+will output
+```yaml
+a: cat
+```
+
+## First matching element from map with numeric condition
+Given a sample.yml file of:
+```yaml
+x:
+  a: 10
+y:
+  a: 100
+z:
+  a: 1
+```
+then
+```bash
+yq 'first(.a > 50)' sample.yml
+```
+will output
+```yaml
+a: 100
+```
+
+## First matching element from nested structure
+Given a sample.yml file of:
+```yaml
+items:
+  - a: banana
+  - a: cat
+  - a: apple
+```
+then
+```bash
+yq '.items | first(.a == "cat")' sample.yml
+```
+will output
+```yaml
+a: cat
+```
+
+## First matching element with no matches
+Given a sample.yml file of:
+```yaml
+- a: banana
+- a: cat
+- a: apple
+```
+then
+```bash
+yq 'first(.a == "dog")' sample.yml
+```
+will output
+```yaml
+```
+
+## First matching element from empty array
+Given a sample.yml file of:
+```yaml
+[]
+```
+then
+```bash
+yq 'first(.a == "cat")' sample.yml
+```
+will output
+```yaml
+```
+
+## First matching element from scalar node
+Given a sample.yml file of:
+```yaml
+hello
+```
+then
+```bash
+yq 'first(. == "hello")' sample.yml
+```
+will output
+```yaml
+```
+
+## First matching element from null node
+Given a sample.yml file of:
+```yaml
+null
+```
+then
+```bash
+yq 'first(. == "hello")' sample.yml
+```
+will output
+```yaml
+```
+
+## First matching element with string condition
+Given a sample.yml file of:
+```yaml
+- a: banana
+- a: cat
+- a: apple
+```
+then
+```bash
+yq 'first(.a | test("^c"))' sample.yml
+```
+will output
+```yaml
+a: cat
+```
+
+## First matching element with length condition
+Given a sample.yml file of:
+```yaml
+- a: hi
+- a: hello
+- a: world
+```
+then
+```bash
+yq 'first(.a | length > 4)' sample.yml
+```
+will output
+```yaml
+a: hello
+```
+
+## First matching element from array of strings
+Given a sample.yml file of:
+```yaml
+- banana
+- cat
+- apple
+```
+then
+```bash
+yq 'first(. == "cat")' sample.yml
+```
+will output
+```yaml
+cat
+```
+
+## First matching element from array of numbers
+Given a sample.yml file of:
+```yaml
+- 10
+- 100
+- 1
+```
+then
+```bash
+yq 'first(. > 50)' sample.yml
+```
+will output
+```yaml
+100
+```
+
+## First element with no RHS from array
+Given a sample.yml file of:
+```yaml
+- 10
+- 100
+- 1
+```
+then
+```bash
+yq 'first' sample.yml
+```
+will output
+```yaml
+10
+```
+
+## First element with no RHS from array of maps
+Given a sample.yml file of:
+```yaml
+- a: 10
+- a: 100
+```
+then
+```bash
+yq 'first' sample.yml
+```
+will output
+```yaml
+a: 10
+```
+
+## No RHS on empty array returns nothing
+Given a sample.yml file of:
+```yaml
+[]
+```
+then
+```bash
+yq 'first' sample.yml
+```
+will output
+```yaml
+```
+
+## No RHS on scalar returns nothing
+Given a sample.yml file of:
+```yaml
+hello
+```
+then
+```bash
+yq 'first' sample.yml
+```
+will output
+```yaml
+```
+
+## No RHS on null returns nothing
+Given a sample.yml file of:
+```yaml
+null
+```
+then
+```bash
+yq 'first' sample.yml
+```
+will output
+```yaml
+```
+

pkg/yqlib/encoder_yaml.go

@@ -9,7 +9,7 @@ import (
 	"strings"
 
 	"github.com/fatih/color"
-	"go.yaml.in/yaml/v3"
+	"go.yaml.in/yaml/v4"
 )
 
 type yamlEncoder struct {

pkg/yqlib/expression_parser.go

@@ -54,6 +54,12 @@ func (p *expressionParserImpl) createExpressionTree(postFixPath []*Operation) (*
 			switch numArgs {
 			case 1:
 				if len(stack) < 1 {
+					// Allow certain unary ops to accept zero args by interpreting missing RHS as nil
+					// TODO - make this more general on OperationType
+					if Operation.OperationType == firstOpType {
+						// no RHS provided; proceed without popping
+						break
+					}
 					return nil, fmt.Errorf("'%v' expects 1 arg but received none", strings.TrimSpace(Operation.StringValue))
 				}
 				remaining, rhs := stack[:len(stack)-1], stack[len(stack)-1]

pkg/yqlib/lexer_participle.go

@@ -118,6 +118,7 @@ var participleYqRules = []*participleYqRule{
 
 	simpleOp("sort_?by", sortByOpType),
 	simpleOp("sort", sortOpType),
+	simpleOp("first", firstOpType),
 
 	simpleOp("reverse", reverseOpType),
 

pkg/yqlib/operation.go

@@ -143,6 +143,7 @@ var delPathsOpType = &operationType{Type: "DEL_PATHS", NumArgs: 1, Precedence: 5
 
 var explodeOpType = &operationType{Type: "EXPLODE", NumArgs: 1, Precedence: 52, Handler: explodeOperator, CheckForPostTraverse: true}
 var sortByOpType = &operationType{Type: "SORT_BY", NumArgs: 1, Precedence: 52, Handler: sortByOperator, CheckForPostTraverse: true}
+var firstOpType = &operationType{Type: "FIRST", NumArgs: 1, Precedence: 52, Handler: firstOperator, CheckForPostTraverse: true}
 var reverseOpType = &operationType{Type: "REVERSE", NumArgs: 0, Precedence: 52, Handler: reverseOperator, CheckForPostTraverse: true}
 var sortOpType = &operationType{Type: "SORT", NumArgs: 0, Precedence: 52, Handler: sortOperator, CheckForPostTraverse: true}
 var shuffleOpType = &operationType{Type: "SHUFFLE", NumArgs: 0, Precedence: 52, Handler: shuffleOperator, CheckForPostTraverse: true}

pkg/yqlib/operator_anchors_aliases_test.go

@@ -464,7 +464,7 @@ var anchorOperatorScenarios = []expressionScenario{
 	},
 	{
 		skipDoc:    true,
-		document:   `{f : {a: &a cat, b: &b {foo: *a}, *a: *b}}`,
+		document:   `{f : {a: &a cat, b: &b {foo: *a}, *a : *b}}`,
 		expression: `explode(.f)`,
 		expected: []string{
 			"D0, P[], (!!map)::{f: {a: cat, b: {foo: cat}, cat: {foo: cat}}}\n",

pkg/yqlib/operator_first.go

@@ -0,0 +1,51 @@
+package yqlib
+
+import "container/list"
+
+func firstOperator(d *dataTreeNavigator, context Context, expressionNode *ExpressionNode) (Context, error) {
+	results := list.New()
+
+	for el := context.MatchingNodes.Front(); el != nil; el = el.Next() {
+		candidate := el.Value.(*CandidateNode)
+
+		// If no RHS expression is provided, simply return the first entry in candidate.Content
+		if expressionNode == nil || expressionNode.RHS == nil {
+			if len(candidate.Content) > 0 {
+				results.PushBack(candidate.Content[0])
+			}
+			continue
+		}
+
+		splatted, err := splat(context.SingleChildContext(candidate), traversePreferences{})
+		if err != nil {
+			return Context{}, err
+		}
+
+		for splatEl := splatted.MatchingNodes.Front(); splatEl != nil; splatEl = splatEl.Next() {
+			splatCandidate := splatEl.Value.(*CandidateNode)
+			// Create a new context for this splatted candidate
+			splatContext := context.SingleChildContext(splatCandidate)
+			// Evaluate the RHS expression against this splatted candidate
+			rhs, err := d.GetMatchingNodes(splatContext, expressionNode.RHS)
+			if err != nil {
+				return Context{}, err
+			}
+
+			includeResult := false
+
+			for resultEl := rhs.MatchingNodes.Front(); resultEl != nil; resultEl = resultEl.Next() {
+				result := resultEl.Value.(*CandidateNode)
+				includeResult = isTruthyNode(result)
+				if includeResult {
+					break
+				}
+			}
+			if includeResult {
+				results.PushBack(splatCandidate)
+				break
+			}
+		}
+
+	}
+	return context.ChildContext(results), nil
+}

pkg/yqlib/operator_first_test.go

@@ -0,0 +1,184 @@
+package yqlib
+
+import "testing"
+
+var firstOperatorScenarios = []expressionScenario{
+	{
+		description: "First matching element from array",
+		document:    "[{a: banana},{a: cat},{a: apple}]",
+		expression:  `first(.a == "cat")`,
+		expected: []string{
+			"D0, P[1], (!!map)::{a: cat}\n",
+		},
+	},
+	{
+		description: "First matching element from array with multiple matches",
+		document:    "[{a: banana},{a: cat},{a: apple},{a: cat}]",
+		expression:  `first(.a == "cat")`,
+		expected: []string{
+			"D0, P[1], (!!map)::{a: cat}\n",
+		},
+	},
+	{
+		description: "First matching element from array with numeric condition",
+		document:    "[{a: 10},{a: 100},{a: 1}]",
+		expression:  `first(.a > 50)`,
+		expected: []string{
+			"D0, P[1], (!!map)::{a: 100}\n",
+		},
+	},
+	{
+		description: "First matching element from array with boolean condition",
+		document:    "[{a: false},{a: true},{a: false}]",
+		expression:  `first(.a == true)`,
+		expected: []string{
+			"D0, P[1], (!!map)::{a: true}\n",
+		},
+	},
+	{
+		description: "First matching element from array with null values",
+		document:    "[{a: null},{a: cat},{a: apple}]",
+		expression:  `first(.a != null)`,
+		expected: []string{
+			"D0, P[1], (!!map)::{a: cat}\n",
+		},
+	},
+	{
+		description: "First matching element from array with complex condition",
+		document:    "[{a: dog, b: 5},{a: cat, b: 3},{a: apple, b: 7}]",
+		expression:  `first(.b > 4)`,
+		expected: []string{
+			"D0, P[0], (!!map)::{a: dog, b: 5}\n",
+		},
+	},
+	{
+		description: "First matching element from map",
+		document:    "x: {a: banana}\ny: {a: cat}\nz: {a: apple}",
+		expression:  `first(.a == "cat")`,
+		expected: []string{
+			"D0, P[y], (!!map)::{a: cat}\n",
+		},
+	},
+	{
+		description: "First matching element from map with numeric condition",
+		document:    "x: {a: 10}\ny: {a: 100}\nz: {a: 1}",
+		expression:  `first(.a > 50)`,
+		expected: []string{
+			"D0, P[y], (!!map)::{a: 100}\n",
+		},
+	},
+	{
+		description: "First matching element from nested structure",
+		document:    "items: [{a: banana},{a: cat},{a: apple}]",
+		expression:  `.items | first(.a == "cat")`,
+		expected: []string{
+			"D0, P[items 1], (!!map)::{a: cat}\n",
+		},
+	},
+	{
+		description: "First matching element with no matches",
+		document:    "[{a: banana},{a: cat},{a: apple}]",
+		expression:  `first(.a == "dog")`,
+		expected:    []string{
+			// No output expected when no matches
+		},
+	},
+	{
+		description: "First matching element from empty array",
+		document:    "[]",
+		expression:  `first(.a == "cat")`,
+		expected:    []string{
+			// No output expected when array is empty
+		},
+	},
+	{
+		description: "First matching element from scalar node",
+		document:    "hello",
+		expression:  `first(. == "hello")`,
+		expected:    []string{
+			// No output expected when node is scalar (no content to splat)
+		},
+	},
+	{
+		description: "First matching element from null node",
+		document:    "null",
+		expression:  `first(. == "hello")`,
+		expected:    []string{
+			// No output expected when node is null (no content to splat)
+		},
+	},
+	{
+		description: "First matching element with string condition",
+		document:    "[{a: banana},{a: cat},{a: apple}]",
+		expression:  `first(.a | test("^c"))`,
+		expected: []string{
+			"D0, P[1], (!!map)::{a: cat}\n",
+		},
+	},
+	{
+		description: "First matching element with length condition",
+		document:    "[{a: hi},{a: hello},{a: world}]",
+		expression:  `first(.a | length > 4)`,
+		expected: []string{
+			"D0, P[1], (!!map)::{a: hello}\n",
+		},
+	},
+	{
+		description: "First matching element from array of strings",
+		document:    "[banana, cat, apple]",
+		expression:  `first(. == "cat")`,
+		expected: []string{
+			"D0, P[1], (!!str)::cat\n",
+		},
+	},
+	{
+		description: "First matching element from array of numbers",
+		document:    "[10, 100, 1]",
+		expression:  `first(. > 50)`,
+		expected: []string{
+			"D0, P[1], (!!int)::100\n",
+		},
+	},
+	// New tests for no RHS (return first child)
+	{
+		description: "First element with no RHS from array",
+		document:    "[10, 100, 1]",
+		expression:  `first`,
+		expected: []string{
+			"D0, P[0], (!!int)::10\n",
+		},
+	},
+	{
+		description: "First element with no RHS from array of maps",
+		document:    "[{a: 10},{a: 100}]",
+		expression:  `first`,
+		expected: []string{
+			"D0, P[0], (!!map)::{a: 10}\n",
+		},
+	},
+	{
+		description: "No RHS on empty array returns nothing",
+		document:    "[]",
+		expression:  `first`,
+		expected:    []string{},
+	},
+	{
+		description: "No RHS on scalar returns nothing",
+		document:    "hello",
+		expression:  `first`,
+		expected:    []string{},
+	},
+	{
+		description: "No RHS on null returns nothing",
+		document:    "null",
+		expression:  `first`,
+		expected:    []string{},
+	},
+}
+
+func TestFirstOperatorScenarios(t *testing.T) {
+	for _, tt := range firstOperatorScenarios {
+		testScenario(t, &tt)
+	}
+	documentOperatorScenarios(t, "first", firstOperatorScenarios)
+}

pkg/yqlib/operators_test.go

@@ -385,13 +385,13 @@ func documentOutput(t *testing.T, w *bufio.Writer, s expressionScenario, formatt
 
 		inputs, err = readDocument(formattedDoc, "sample.yml", 0)
 		if err != nil {
-			t.Error(err, s.document, s.expression)
+			t.Error(err, formattedDoc, "exp: "+s.expression)
 			return
 		}
 		if s.document2 != "" {
 			moreInputs, err := readDocument(formattedDoc2, "another.yml", 1)
 			if err != nil {
-				t.Error(err, s.document, s.expression)
+				t.Error(err, formattedDoc2, "exp: "+s.expression)
 				return
 			}
 			inputs.PushBackList(moreInputs)

pkg/yqlib/printer_node_info.go

@@ -5,7 +5,7 @@ import (
 	"container/list"
 	"io"
 
-	"go.yaml.in/yaml/v3"
+	"go.yaml.in/yaml/v4"
 )
 
 type nodeInfoPrinter struct {