Added pipe and length docs, fix pipe precedence

pkg/yqlib/operators.go

@@ -2,7 +2,6 @@ package yqlib
 
 import (
 	"container/list"
-	"fmt"
 
 	"gopkg.in/yaml.v3"
 )
@@ -20,14 +19,6 @@ func EmptyOperator(d *dataTreeNavigator, matchingNodes *list.List, pathNode *Pat
 	return list.New(), nil
 }
 
-func PipeOperator(d *dataTreeNavigator, matchingNodes *list.List, pathNode *PathTreeNode) (*list.List, error) {
-	lhs, err := d.GetMatchingNodes(matchingNodes, pathNode.Lhs)
-	if err != nil {
-		return nil, err
-	}
-	return d.GetMatchingNodes(lhs, pathNode.Rhs)
-}
-
 func createBooleanCandidate(owner *CandidateNode, value bool) *CandidateNode {
 	valString := "true"
 	if !value {
@@ -42,29 +33,3 @@ func nodeToMap(candidate *CandidateNode) *list.List {
 	elMap.PushBack(candidate)
 	return elMap
 }
-
-func LengthOperator(d *dataTreeNavigator, matchMap *list.List, pathNode *PathTreeNode) (*list.List, error) {
-	log.Debugf("-- lengthOperation")
-	var results = list.New()
-
-	for el := matchMap.Front(); el != nil; el = el.Next() {
-		candidate := el.Value.(*CandidateNode)
-		var length int
-		switch candidate.Node.Kind {
-		case yaml.ScalarNode:
-			length = len(candidate.Node.Value)
-		case yaml.MappingNode:
-			length = len(candidate.Node.Content) / 2
-		case yaml.SequenceNode:
-			length = len(candidate.Node.Content)
-		default:
-			length = 0
-		}
-
-		node := &yaml.Node{Kind: yaml.ScalarNode, Value: fmt.Sprintf("%v", length), Tag: "!!int"}
-		lengthCand := &CandidateNode{Node: node, Document: candidate.Document, Path: candidate.Path}
-		results.PushBack(lengthCand)
-	}
-
-	return results, nil
-}