Dont recurse into scalar nodes

Fixes https://github.com/mikefarah/yq/issues/375

cmd/commands_test.go

@@ -2005,6 +2005,20 @@ func TestDeleteYamlArrayCmd(t *testing.T) {
 	test.AssertResult(t, expectedOutput, result.Output)
 }
 
+func TestReadExpression(t *testing.T) {
+	content := `name: value`
+	filename := test.WriteTempYamlFile(content)
+	defer test.RemoveTempYamlFile(filename)
+	cmd := getRootCommand()
+	result := test.RunCmd(cmd, fmt.Sprintf("r %s (x==f)", filename))
+	if result.Error != nil {
+		t.Error(result.Error)
+	}
+
+	expectedOutput := ``
+	test.AssertResult(t, expectedOutput, result.Output)
+}
+
 func TestDeleteYamlArrayExpressionCmd(t *testing.T) {
 	content := `- name: fred
 - name: cat

pkg/yqlib/path_parser.go

@@ -4,6 +4,8 @@ import (
 	"fmt"
 	"strconv"
 	"strings"
+
+	yaml "gopkg.in/yaml.v3"
 )
 
 type PathParser interface {
@@ -45,7 +47,7 @@ func (p *pathParser) MatchesNextPathElement(nodeContext NodeContext, nodeKey str
 	}
 	var headString = fmt.Sprintf("%v", head)
 
-	if strings.Contains(headString, "==") {
+	if strings.Contains(headString, "==") && nodeContext.Node.Kind != yaml.ScalarNode {
 		log.Debug("ooh deep recursion time")
 		result := strings.SplitN(headString, "==", 2)
 		path := strings.TrimSpace(result[0])