simple anchors

pkg/yqlib/treeops/candidate_node.go

@@ -31,6 +31,7 @@ func (n *CandidateNode) UpdateFrom(other *CandidateNode) {
 	n.UpdateAttributesFrom(other)
 	n.Node.Content = other.Node.Content
 	n.Node.Value = other.Node.Value
+	n.Node.Alias = other.Node.Alias
 }
 
 func (n *CandidateNode) UpdateAttributesFrom(other *CandidateNode) {

pkg/yqlib/treeops/lib.go

@@ -49,8 +49,6 @@ var Select = &OperationType{Type: "SELECT", NumArgs: 1, Precedence: 50, Handler:
 
 var DeleteChild = &OperationType{Type: "DELETE", NumArgs: 2, Precedence: 40, Handler: DeleteChildOperator}
 
-// var Splat = &OperationType{Type: "SPLAT", NumArgs: 0, Precedence: 40, Handler: SplatOperator}
-
 // var Exists = &OperationType{Type: "Length", NumArgs: 2, Precedence: 35}
 // filters matches if they have the existing path
 
@@ -59,6 +57,7 @@ type Operation struct {
 	Value         interface{}
 	StringValue   string
 	CandidateNode *CandidateNode // used for Value Path elements
+	Preferences   interface{}
 }
 
 func CreateValueOperation(value interface{}, stringValue string) *Operation {
@@ -132,6 +131,8 @@ func NodeToString(node *CandidateNode) string {
 	tag := value.Tag
 	if value.Kind == yaml.DocumentNode {
 		tag = "doc"
+	} else if value.Kind == yaml.AliasNode {
+		tag = "alias"
 	}
 	return fmt.Sprintf(`D%v, P%v, (%v)::%v`, node.Document, node.Path, tag, buf.String())
 }

pkg/yqlib/treeops/operator_multilpy.go

@@ -107,7 +107,7 @@ func applyAssignment(d *dataTreeNavigator, pathIndexToStartFrom int, lhs *Candid
 	lhsPath := rhs.Path[pathIndexToStartFrom:]
 
 	assignmentOp := &Operation{OperationType: AssignAttributes}
-	if rhs.Node.Kind == yaml.ScalarNode {
+	if rhs.Node.Kind == yaml.ScalarNode || rhs.Node.Kind == yaml.AliasNode {
 		assignmentOp.OperationType = Assign
 	}
 	rhsOp := &Operation{OperationType: ValueOp, CandidateNode: rhs}

pkg/yqlib/treeops/operator_multiply_test.go

@@ -81,6 +81,20 @@ b:
 			"D0, P[], (!!map)::{a: {c: cat}}\n",
 		},
 	},
+	{
+		document:   `{a: &cat {c: frog}, b: {f: *cat}, c: {g: thongs}}`,
+		expression: `.c * .b`,
+		expected: []string{
+			"D0, P[c], (!!map)::{g: thongs, f: *cat}\n",
+		},
+	},
+	{
+		document:   `{a: {c: &cat frog}, b: {f: *cat}, c: {g: thongs}}`,
+		expression: `.c * .a`,
+		expected: []string{
+			"D0, P[c], (!!map)::{g: thongs, c: frog}\n",
+		},
+	},
 }
 
 func TestMultiplyOperatorScenarios(t *testing.T) {

pkg/yqlib/treeops/operator_recursive_descent.go

@@ -2,6 +2,8 @@ package treeops
 
 import (
 	"container/list"
+
+	"gopkg.in/yaml.v3"
 )
 
 func RecursiveDescentOperator(d *dataTreeNavigator, matchMap *list.List, pathNode *PathTreeNode) (*list.List, error) {
@@ -24,14 +26,17 @@ func recursiveDecent(d *dataTreeNavigator, results *list.List, matchMap *list.Li
 		log.Debugf("Recursive Decent, added %v", NodeToString(candidate))
 		results.PushBack(candidate)
 
-		children, err := Splat(d, nodeToMap(candidate))
+		if candidate.Node.Kind != yaml.AliasNode {
 
-		if err != nil {
-			return err
-		}
-		err = recursiveDecent(d, results, children)
-		if err != nil {
-			return err
+			children, err := Splat(d, nodeToMap(candidate))
+
+			if err != nil {
+				return err
+			}
+			err = recursiveDecent(d, results, children)
+			if err != nil {
+				return err
+			}
 		}
 	}
 	return nil

pkg/yqlib/treeops/operator_recursive_descent_test.go

@@ -50,6 +50,16 @@ var recursiveDescentOperatorScenarios = []expressionScenario{
 			"D0, P[2], (!!bool)::true\n",
 		},
 	},
+	{
+		document:   `{a: &cat {c: frog}, b: *cat}`,
+		expression: `..`,
+		expected: []string{
+			"D0, P[], (!!map)::{a: &cat {c: frog}, b: *cat}\n",
+			"D0, P[a], (!!map)::&cat {c: frog}\n",
+			"D0, P[a c], (!!str)::frog\n",
+			"D0, P[b], (alias)::*cat\n",
+		},
+	},
 }
 
 func TestRecursiveDescentOperatorScenarios(t *testing.T) {

pkg/yqlib/treeops/operator_traverse_path.go

@@ -8,8 +8,13 @@ import (
 	"gopkg.in/yaml.v3"
 )
 
+type TraversePreferences struct {
+	DontFollowAlias bool
+}
+
 func Splat(d *dataTreeNavigator, matches *list.List) (*list.List, error) {
-	splatOperation := &Operation{OperationType: TraversePath, Value: "[]"}
+	preferences := &TraversePreferences{DontFollowAlias: true}
+	splatOperation := &Operation{OperationType: TraversePath, Value: "[]", Preferences: preferences}
 	splatTreeNode := &PathTreeNode{Operation: splatOperation}
 	return TraversePathOperator(d, matches, splatTreeNode)
 }
@@ -33,14 +38,20 @@ func TraversePathOperator(d *dataTreeNavigator, matchMap *list.List, pathNode *P
 	return matchingNodeMap, nil
 }
 
-func traverse(d *dataTreeNavigator, matchingNode *CandidateNode, pathNode *Operation) ([]*CandidateNode, error) {
+func traverse(d *dataTreeNavigator, matchingNode *CandidateNode, operation *Operation) ([]*CandidateNode, error) {
 	log.Debug("Traversing %v", NodeToString(matchingNode))
 	value := matchingNode.Node
 
-	if value.Tag == "!!null" && pathNode.Value != "[]" {
+	followAlias := true
+
+	// if operation.Preferences != nil {
+	// 	followAlias = !operation.Preferences.(*TraversePreferences).DontFollowAlias
+	// }
+
+	if value.Tag == "!!null" && operation.Value != "[]" {
 		log.Debugf("Guessing kind")
 		// we must ahve added this automatically, lets guess what it should be now
-		switch pathNode.Value.(type) {
+		switch operation.Value.(type) {
 		case int, int64:
 			log.Debugf("probably an array")
 			value.Kind = yaml.SequenceNode
@@ -54,33 +65,24 @@ func traverse(d *dataTreeNavigator, matchingNode *CandidateNode, pathNode *Opera
 	switch value.Kind {
 	case yaml.MappingNode:
 		log.Debug("its a map with %v entries", len(value.Content)/2)
-		return traverseMap(matchingNode, pathNode)
+		return traverseMap(matchingNode, operation)
 
 	case yaml.SequenceNode:
 		log.Debug("its a sequence of %v things!", len(value.Content))
-		return traverseArray(matchingNode, pathNode)
-	// 	default:
+		return traverseArray(matchingNode, operation)
 
-	// 		if head == "+" {
-	// 			return n.appendArray(value, head, tail, pathStack)
-	// 		} else if len(value.Content) == 0 && head == "**" {
-	// 			return n.navigationStrategy.Visit(nodeContext)
-	// 		}
-	// 		return n.splatArray(value, head, tail, pathStack)
-	// 	}
-	// case yaml.AliasNode:
-	// 	log.Debug("its an alias!")
-	// 	DebugNode(value.Alias)
-	// 	if n.navigationStrategy.FollowAlias(nodeContext) {
-	// 		log.Debug("following the alias")
-	// 		return n.recurse(value.Alias, head, tail, pathStack)
-	// 	}
-	// 	return nil
+	case yaml.AliasNode:
+		log.Debug("its an alias!")
+		if followAlias {
+			matchingNode.Node = matchingNode.Node.Alias
+			return traverse(d, matchingNode, operation)
+		}
+		return []*CandidateNode{matchingNode}, nil
 	case yaml.DocumentNode:
 		log.Debug("digging into doc node")
 		return traverse(d, &CandidateNode{
 			Node:     matchingNode.Node.Content[0],
-			Document: matchingNode.Document}, pathNode)
+			Document: matchingNode.Document}, operation)
 	default:
 		return nil, nil
 	}

pkg/yqlib/treeops/operator_traverse_path_test.go

@@ -83,6 +83,27 @@ var traversePathOperatorScenarios = []expressionScenario{
 			"D0, P[a mad], (!!str)::things\n",
 		},
 	},
+	{
+		document:   `{a: &cat {c: frog}, b: *cat}`,
+		expression: `.b`,
+		expected: []string{
+			"D0, P[b], (alias)::*cat\n",
+		},
+	},
+	{
+		document:   `{a: &cat {c: frog}, b: *cat}`,
+		expression: `.b.[]`,
+		expected: []string{
+			"D0, P[b c], (!!str)::frog\n",
+		},
+	},
+	{
+		document:   `{a: &cat {c: frog}, b: *cat}`,
+		expression: `.b.c`,
+		expected: []string{
+			"D0, P[b c], (!!str)::frog\n",
+		},
+	},
 }
 
 func TestTraversePathOperatorScenarios(t *testing.T) {