Added parents operator

Author: mikefarah

pkg/yqlib/doc/operators/parent.md

@@ -56,6 +56,29 @@ will output
 sam
 ```
 
+## Get parents
+Match all parents
+
+Given a sample.yml file of:
+```yaml
+a:
+  b:
+    c: cat
+```
+then
+```bash
+yq '.a.b.c | parents' sample.yml
+```
+will output
+```yaml
+- c: cat
+- b:
+    c: cat
+- a:
+    b:
+      c: cat
+```
+
 ## N-th parent
 You can optionally supply the number of levels to go up for the parent, the default being 1.
 

pkg/yqlib/lexer_participle.go

@@ -130,6 +130,7 @@ var participleYqRules = []*participleYqRule{
 	simpleOp("contains", containsOpType),
 	simpleOp("split", splitStringOpType),
 
+	simpleOp("parents", getParentsOpType),
 	{"ParentWithLevel", `parent\([0-9]+\)`, parentWithLevel(), 0},
 	{"ParentWithDefaultLevel", `parent`, parentWithDefaultLevel(), 0},
 

pkg/yqlib/operation.go

@@ -128,6 +128,7 @@ var getKindOpType = &operationType{Type: "GET_KIND", NumArgs: 0, Precedence: 50,
 var getKeyOpType = &operationType{Type: "GET_KEY", NumArgs: 0, Precedence: 50, Handler: getKeyOperator}
 var isKeyOpType = &operationType{Type: "IS_KEY", NumArgs: 0, Precedence: 50, Handler: isKeyOperator}
 var getParentOpType = &operationType{Type: "GET_PARENT", NumArgs: 0, Precedence: 50, Handler: getParentOperator}
+var getParentsOpType = &operationType{Type: "GET_PARENTS", NumArgs: 0, Precedence: 50, Handler: getParentsOperator}
 
 var getCommentOpType = &operationType{Type: "GET_COMMENT", NumArgs: 0, Precedence: 50, Handler: getCommentsOperator}
 var getAnchorOpType = &operationType{Type: "GET_ANCHOR", NumArgs: 0, Precedence: 50, Handler: getAnchorOperator}

pkg/yqlib/operator_parent.go

@@ -6,6 +6,26 @@ type parentOpPreferences struct {
 	Level int
 }
 
+func getParentsOperator(_ *dataTreeNavigator, context Context, _ *ExpressionNode) (Context, error) {
+	log.Debugf("getParentsOperator")
+
+	var results = list.New()
+
+	for el := context.MatchingNodes.Front(); el != nil; el = el.Next() {
+		candidate := el.Value.(*CandidateNode)
+		parentsList := &CandidateNode{Kind: SequenceNode, Tag: "!!seq"}
+		parent := candidate.Parent
+		for parent != nil {
+			parentsList.AddChild(parent)
+			parent = parent.Parent
+		}
+		results.PushBack(parentsList)
+	}
+
+	return context.ChildContext(results), nil
+
+}
+
 func getParentOperator(_ *dataTreeNavigator, context Context, expressionNode *ExpressionNode) (Context, error) {
 	log.Debugf("getParentOperator")
 

pkg/yqlib/operator_parent_test.go

@@ -29,6 +29,15 @@ var parentOperatorScenarios = []expressionScenario{
 			"D0, P[b name], (!!str)::sam\n",
 		},
 	},
+	{
+		description:    "Get parents",
+		subdescription: "Match all parents",
+		document:       "{a: {b: {c: cat} } }",
+		expression:     `.a.b.c | parents`,
+		expected: []string{
+			"D0, P[], (!!seq)::- {c: cat}\n- {b: {c: cat}}\n- {a: {b: {c: cat}}}\n",
+		},
+	},
 	{
 		description:    "N-th parent",
 		subdescription: "You can optionally supply the number of levels to go up for the parent, the default being 1.",