Support non string map keys (#756)

* fix map keys misencoding to string

* Add unit tests

* Add tests for decoder with unconventional map keys

---------

Co-authored-by: Zsolt Herczeg <herczegzsolt@herczegzsolt.hu>

decode_test.go

@@ -494,6 +494,24 @@ func TestDecoder(t *testing.T) {
 			value:  map[string]interface{}{"a": "50cent_of_dollar"},
 		},
 
+		// Unconventional keys
+		{
+			source: "1: v\n",
+			value:  map[int]string{1: "v"},
+		},
+		{
+			source: "1.1: v\n",
+			value:  map[float64]string{1.1: "v"},
+		},
+		{
+			source: "true: v\n",
+			value:  map[bool]string{true: "v"},
+		},
+		{
+			source: "2015-01-01T00:00:00Z: v\n",
+			value:  map[time.Time]string{time.Date(2015, 1, 1, 0, 0, 0, 0, time.UTC): "v"},
+		},
+
 		// Nulls
 		{
 			source: "null",

encode.go

@@ -712,9 +712,15 @@ func (e *Encoder) encodeMap(ctx context.Context, value reflect.Value, column int
 			anchorNode.Value = encoded
 			encoded = anchorNode
 		}
+
+		kn, err := e.encodeValue(ctx, reflect.ValueOf(key), column)
+		keyNode, ok := kn.(ast.MapKeyNode)
+		if !ok || err != nil {
+			keyNode = e.encodeString(fmt.Sprint(key), column)
+		}
 		node.Values = append(node.Values, ast.MappingValue(
 			nil,
-			e.encodeString(keyText, column),
+			keyNode,
 			encoded,
 		))
 		e.setSmartAnchor(vRef, keyText)

encode_test.go

@@ -187,6 +187,26 @@ func TestEncoder(t *testing.T) {
 			map[string]string{"a": "-"},
 			nil,
 		},
+		{
+			"1: v\n",
+			map[int]string{1: "v"},
+			nil,
+		},
+		{
+			"1.1: v\n",
+			map[float64]string{1.1: "v"},
+			nil,
+		},
+		{
+			"true: v\n",
+			map[bool]string{true: "v"},
+			nil,
+		},
+		{
+			"2015-01-01T00:00:00Z: v\n",
+			map[time.Time]string{time.Date(2015, 1, 1, 0, 0, 0, 0, time.UTC): "v"},
+			nil,
+		},
 		{
 			"123\n",
 			123,