wip

src/model/zcl_protobuf2_enum.clas.abap

@@ -1,7 +1,12 @@
 CLASS zcl_protobuf2_enum DEFINITION PUBLIC.
   PUBLIC SECTION.
+    INTERFACES zif_protobuf2_serializable.
 ENDCLASS.
 
 CLASS zcl_protobuf2_enum IMPLEMENTATION.
 
+  METHOD zif_protobuf2_serializable~serialize.
+    ASSERT 1 = 'todo'.
+  ENDMETHOD.
+
 ENDCLASS.

src/model/zcl_protobuf2_field.clas.abap

@@ -1,5 +1,7 @@
 CLASS zcl_protobuf2_field DEFINITION PUBLIC.
   PUBLIC SECTION.
+    INTERFACES zif_protobuf2_serializable.
+
     DATA mv_label        TYPE string.
     DATA mv_type         TYPE string.
     DATA mv_field_name   TYPE string.
@@ -8,4 +10,8 @@ ENDCLASS.
 
 CLASS zcl_protobuf2_field IMPLEMENTATION.
 
+  METHOD zif_protobuf2_serializable~serialize.
+    ASSERT 1 = 'todo'.
+  ENDMETHOD.
+
 ENDCLASS.

src/model/zcl_protobuf2_file.clas.abap

@@ -1,10 +1,20 @@
 CLASS zcl_protobuf2_file DEFINITION PUBLIC.
   PUBLIC SECTION.
 * https://protobuf.dev/reference/protobuf/proto2-spec/#proto_file
+
+    INTERFACES zif_protobuf2_serializable.
+
     DATA mt_messages TYPE STANDARD TABLE OF REF TO zcl_protobuf2_message WITH EMPTY KEY.
 *    DATA mt_enums TYPE STANDARD TABLE OF REF TO zcl_protobuf2_enum WITH EMPTY KEY.
 ENDCLASS.
 
 CLASS zcl_protobuf2_file IMPLEMENTATION.
 
+  METHOD zif_protobuf2_serializable~serialize.
+    rv_string = |syntax = "proto2";\n|.
+    LOOP AT mt_messages INTO DATA(lo_message).
+      rv_string = rv_string && lo_message->zif_protobuf2_serializable~serialize( ).
+    ENDLOOP.
+  ENDMETHOD.
+
 ENDCLASS.

src/model/zcl_protobuf2_message.clas.abap

@@ -1,6 +1,7 @@
 CLASS zcl_protobuf2_message DEFINITION PUBLIC.
   PUBLIC SECTION.
 * https://protobuf.dev/reference/protobuf/proto2-spec/#message_definition
+    INTERFACES zif_protobuf2_serializable.
     METHODS constructor IMPORTING iv_name TYPE string.
     DATA mv_name TYPE string.
     DATA mt_fields TYPE STANDARD TABLE OF REF TO zcl_protobuf2_field WITH EMPTY KEY.
@@ -12,4 +13,9 @@ CLASS zcl_protobuf2_message IMPLEMENTATION.
     mv_name = iv_name.
   ENDMETHOD.
 
+  METHOD zif_protobuf2_serializable~serialize.
+    ASSERT 1 = 'todo'.
+*    rv_string =
+  ENDMETHOD.
+
 ENDCLASS.