fixing exposed functions and interfaces

pkg/yqlib/all_at_once_evaluator.go

@@ -2,11 +2,13 @@ package yqlib
 
 import "container/list"
 
-/**
-	Loads all yaml documents of all files given into memory, then runs the given expression once.
-**/
+// A yaml expression evaluator that runs the expression once against all files/nodes in memory.
 type Evaluator interface {
 	EvaluateFiles(expression string, filenames []string, printer Printer) error
+
+	// Runs the expression once against the list of candidate nodes, returns the
+	// resulting nodes.
+	EvaluateNodes(expression string, inputCandidateNodes *list.List) (*list.List, error)
 }
 
 type allAtOnceEvaluator struct {
@@ -18,12 +20,17 @@ func NewAllAtOnceEvaluator() Evaluator {
 	return &allAtOnceEvaluator{treeNavigator: NewDataTreeNavigator(), treeCreator: NewPathTreeCreator()}
 }
 
-func (e *allAtOnceEvaluator) EvaluateFiles(expression string, filenames []string, printer Printer) error {
-	fileIndex := 0
+func (e *allAtOnceEvaluator) EvaluateNodes(expression string, inputCandidates *list.List) (*list.List, error) {
 	node, err := treeCreator.ParsePath(expression)
 	if err != nil {
-		return err
+		return nil, err
 	}
+	return treeNavigator.GetMatchingNodes(inputCandidates, node)
+}
+
+func (e *allAtOnceEvaluator) EvaluateFiles(expression string, filenames []string, printer Printer) error {
+	fileIndex := 0
+
 	var allDocuments *list.List = list.New()
 	for _, filename := range filenames {
 		reader, err := readStream(filename)
@@ -37,7 +44,7 @@ func (e *allAtOnceEvaluator) EvaluateFiles(expression string, filenames []string
 		allDocuments.PushBackList(fileDocuments)
 		fileIndex = fileIndex + 1
 	}
-	matches, err := treeNavigator.GetMatchingNodes(allDocuments, node)
+	matches, err := e.EvaluateNodes(expression, allDocuments)
 	if err != nil {
 		return err
 	}