put comments on key node instead

examples/small.properties

@@ -2,5 +2,9 @@
 
 # things and stuff
 this.is = a properties file
+
+
+this.cat.0 = free
+# this one is important
 # another thing
-this.another = a properties file
+this.cat.1 = meow

pkg/yqlib/decoder_properties.go

@@ -2,6 +2,7 @@ package yqlib
 
 import (
 	"bytes"
+	"fmt"
 	"io"
 	"strconv"
 	"strings"
@@ -47,17 +48,50 @@ func (dec *propertiesDecoder) processComment(c string) string {
 	return "# " + c
 }
 
-func (dec *propertiesDecoder) applyProperty(properties *properties.Properties, context Context, key string) error {
+func (dec *propertiesDecoder) applyPropertyComments(context Context, path []interface{}, comments []string) error {
+	assignmentOp := &Operation{OperationType: assignOpType, Preferences: assignPreferences{}}
+
+	rhsCandidateNode := &CandidateNode{
+		Path: path,
+		Node: &yaml.Node{
+			Tag:         "!!str",
+			Value:       fmt.Sprintf("%v", path[len(path)-1]),
+			HeadComment: dec.processComment(strings.Join(comments, "\n")),
+			Kind:        yaml.ScalarNode,
+		},
+	}
+
+	rhsCandidateNode.Node.Tag = guessTagFromCustomType(rhsCandidateNode.Node)
+
+	rhsOp := &Operation{OperationType: valueOpType, CandidateNode: rhsCandidateNode}
+
+	assignmentOpNode := &ExpressionNode{
+		Operation: assignmentOp,
+		LHS:       createTraversalTree(path, traversePreferences{}, true),
+		RHS:       &ExpressionNode{Operation: rhsOp},
+	}
+
+	_, err := dec.d.GetMatchingNodes(context, assignmentOpNode)
+	return err
+}
+
+// TODO: test comment on array
+func (dec *propertiesDecoder) applyProperty(context Context, properties *properties.Properties, key string) error {
 	value, _ := properties.Get(key)
 	path := parsePropKey(key)
 
-	IMPROVEMENT - target the key node with the comment, set as a header comment instead.
+	propertyComments := properties.GetComments(key)
+	if len(propertyComments) > 0 {
+		err := dec.applyPropertyComments(context, path, propertyComments)
+		if err != nil {
+			return nil
+		}
+	}
 
 	rhsNode := &yaml.Node{
 		Value: value,
 		Tag:   "!!str",
 		Kind:  yaml.ScalarNode,
-		LineComment: dec.processComment(strings.Join(properties.GetComments(key), "\n")),
 	}
 
 	rhsNode.Tag = guessTagFromCustomType(rhsNode)
@@ -111,7 +145,7 @@ func (dec *propertiesDecoder) Decode() (*CandidateNode, error) {
 	context = context.SingleChildContext(rootMap)
 
 	for _, key := range properties.Keys() {
-		if err := dec.applyProperty(properties, context, key); err != nil {
+		if err := dec.applyProperty(context, properties, key); err != nil {
 			return nil, err
 		}