Can specify parent levels #1970

pkg/yqlib/doc/operators/parent.md

@@ -37,6 +37,43 @@ fruit: banana
 name: sam
 ```
 
+## N-th parent
+You can optionally supply the number of levels to go up for the parent, the default being 1.
+
+Given a sample.yml file of:
+```yaml
+a:
+  b:
+    c: cat
+```
+then
+```bash
+yq '.a.b.c | parent(2)' sample.yml
+```
+will output
+```yaml
+b:
+  c: cat
+```
+
+## N-th parent - another level
+Given a sample.yml file of:
+```yaml
+a:
+  b:
+    c: cat
+```
+then
+```bash
+yq '.a.b.c | parent(3)' sample.yml
+```
+will output
+```yaml
+a:
+  b:
+    c: cat
+```
+
 ## No parent
 Given a sample.yml file of:
 ```yaml

pkg/yqlib/lexer_participle.go

@@ -130,7 +130,9 @@ var participleYqRules = []*participleYqRule{
 
 	simpleOp("contains", containsOpType),
 	simpleOp("split", splitStringOpType),
-	simpleOp("parent", getParentOpType),
+
+	{"ParentWithLevel", `parent\([0-9]+\)`, parentWithLevel(), 0},
+	{"ParentWithDefaultLevel", `parent`, parentWithDefaultLevel(), 0},
 
 	simpleOp("keys", keysOpType),
 	simpleOp("key", getKeyOpType),
@@ -501,6 +503,28 @@ func numberValue() yqAction {
 	}
 }
 
+func parentWithLevel() yqAction {
+	return func(rawToken lexer.Token) (*token, error) {
+		value := rawToken.Value
+		var level, errParsingInt = extractNumberParameter(value)
+		if errParsingInt != nil {
+			return nil, errParsingInt
+		}
+
+		prefs := parentOpPreferences{Level: level}
+		op := &Operation{OperationType: getParentOpType, Value: getParentOpType.Type, StringValue: value, Preferences: prefs}
+		return &token{TokenType: operationToken, Operation: op}, nil
+	}
+}
+
+func parentWithDefaultLevel() yqAction {
+	return func(rawToken lexer.Token) (*token, error) {
+		prefs := parentOpPreferences{Level: 1}
+		op := &Operation{OperationType: getParentOpType, Value: getParentOpType.Type, StringValue: getParentOpType.Type, Preferences: prefs}
+		return &token{TokenType: operationToken, Operation: op}, nil
+	}
+}
+
 func encodeParseIndent(outputFormat *Format) yqAction {
 	return func(rawToken lexer.Token) (*token, error) {
 		value := rawToken.Value

pkg/yqlib/operator_parent.go

@@ -2,15 +2,30 @@ package yqlib
 
 import "container/list"
 
-func getParentOperator(_ *dataTreeNavigator, context Context, _ *ExpressionNode) (Context, error) {
+type parentOpPreferences struct {
+	Level int
+}
+
+func getParentOperator(_ *dataTreeNavigator, context Context, expressionNode *ExpressionNode) (Context, error) {
 	log.Debugf("getParentOperator")
 
 	var results = list.New()
 
+	prefs := expressionNode.Operation.Preferences.(parentOpPreferences)
+
 	for el := context.MatchingNodes.Front(); el != nil; el = el.Next() {
 		candidate := el.Value.(*CandidateNode)
-		if candidate.Parent != nil {
-			results.PushBack(candidate.Parent)
+		currentLevel := 0
+		for currentLevel < prefs.Level && candidate != nil {
+			log.Debugf("currentLevel: %v, desired: %v", currentLevel, prefs.Level)
+			log.Debugf("candidate: %v", NodeToString(candidate))
+			candidate = candidate.Parent
+			currentLevel++
+		}
+
+		log.Debugf("found candidate: %v", NodeToString(candidate))
+		if candidate != nil {
+			results.PushBack(candidate)
 		}
 	}
 

pkg/yqlib/operator_parent_test.go

@@ -21,6 +21,23 @@ var parentOperatorScenarios = []expressionScenario{
 			"D0, P[b], (!!map)::{fruit: banana, name: sam}\n",
 		},
 	},
+	{
+		description:    "N-th parent",
+		subdescription: "You can optionally supply the number of levels to go up for the parent, the default being 1.",
+		document:       "a:\n  b:\n    c: cat\n",
+		expression:     `.a.b.c | parent(2)`,
+		expected: []string{
+			"D0, P[a], (!!map)::b:\n    c: cat\n",
+		},
+	},
+	{
+		description: "N-th parent - another level",
+		document:    "a:\n  b:\n    c: cat\n",
+		expression:  `.a.b.c | parent(3)`,
+		expected: []string{
+			"D0, P[], (!!map)::a:\n    b:\n        c: cat\n",
+		},
+	},
 	{
 		description: "No parent",
 		document:    `{}`,