Simplify declarations of x-macro FLATBUFFERS_TD (#5638)

include/flatbuffers/idl.h

@@ -91,6 +91,20 @@ switch (type) {
 }
 */
 
+// If not all FLATBUFFERS_GEN_() arguments are necessary for implementation 
+// of FLATBUFFERS_TD, you can use a variadic macro (with __VA_ARGS__ if needed).
+// In the above example, only CTYPE is used to generate the code, it can be rewritten:
+
+/*
+switch (type) {
+  #define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, ...) \
+    case BASE_TYPE_ ## ENUM: \
+      // do something specific to CTYPE here
+    FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
+  #undef FLATBUFFERS_TD
+}
+*/
+
 #define FLATBUFFERS_GEN_TYPES(TD) \
         FLATBUFFERS_GEN_TYPES_SCALAR(TD) \
         FLATBUFFERS_GEN_TYPES_POINTER(TD) \
@@ -101,15 +115,13 @@ switch (type) {
 __extension__  // Stop GCC complaining about trailing comma with -Wpendantic.
 #endif
 enum BaseType {
-  #define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, \
-                         RTYPE, KTYPE) \
+  #define FLATBUFFERS_TD(ENUM, ...) \
     BASE_TYPE_ ## ENUM,
     FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
   #undef FLATBUFFERS_TD
 };
 
-#define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, \
-                       RTYPE, KTYPE) \
+#define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, ...) \
   static_assert(sizeof(CTYPE) <= sizeof(largest_scalar_t), \
                 "define largest_scalar_t as " #CTYPE);
   FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)

src/idl_gen_cpp.cpp

@@ -545,8 +545,7 @@ class CppGenerator : public BaseGenerator {
   std::string GenTypeBasic(const Type &type, bool user_facing_type) const {
     // clang-format off
     static const char *const ctypename[] = {
-    #define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, \
-                           RTYPE, KTYPE) \
+      #define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, ...) \
         #CTYPE,
         FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
       #undef FLATBUFFERS_TD

src/idl_gen_csharp.cpp

@@ -119,8 +119,7 @@ class CSharpGenerator : public BaseGenerator {
   std::string GenTypeBasic(const Type &type, bool enableLangOverrides) const {
     // clang-format off
     static const char * const csharp_typename[] = {
-    #define FLATBUFFERS_TD(ENUM, IDLTYPE, \
-        CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, RTYPE, KTYPE) \
+      #define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, JTYPE, GTYPE, NTYPE, ...) \
         #NTYPE,
         FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
       #undef FLATBUFFERS_TD

src/idl_gen_go.cpp

@@ -1162,15 +1162,14 @@ class GoGenerator : public BaseGenerator {
   }
 
   std::string GenTypeBasic(const Type &type) {
-    static const char *ctypename[] = {
     // clang-format off
-      #define FLATBUFFERS_TD(ENUM, IDLTYPE, \
-        CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, RTYPE, KTYPE) \
+    static const char *ctypename[] = {
+      #define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, JTYPE, GTYPE, ...) \
         #GTYPE,
         FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
       #undef FLATBUFFERS_TD
-      // clang-format on
     };
+    // clang-format on
     return ctypename[type.base_type];
   }
 

src/idl_gen_java.cpp

@@ -143,14 +143,12 @@ class JavaGenerator : public BaseGenerator {
   std::string GenTypeBasic(const Type &type) const {
     // clang-format off
     static const char * const java_typename[] = {
-    #define FLATBUFFERS_TD(ENUM, IDLTYPE, \
-        CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, RTYPE, KTYPE) \
+      #define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, JTYPE, ...) \
         #JTYPE,
         FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
       #undef FLATBUFFERS_TD
     };
     // clang-format on
-
     return java_typename[type.base_type];
   }
 

src/idl_gen_kotlin.cpp

@@ -145,8 +145,8 @@ class KotlinGenerator : public BaseGenerator {
         #KTYPE,
         FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
       #undef FLATBUFFERS_TD
-      // clang-format on
     };
+    // clang-format on
     return kotlin_typename[type];
   }
 

src/idl_gen_lobster.cpp

@@ -83,15 +83,15 @@ class LobsterGenerator : public BaseGenerator {
 
   // This uses Python names for now..
   std::string GenTypeBasic(const Type &type) {
-    static const char *ctypename[] = {
     // clang-format off
+    static const char *ctypename[] = {
       #define FLATBUFFERS_TD(ENUM, IDLTYPE, \
-        CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, RTYPE, KTYPE) \
+              CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, ...) \
         #PTYPE,
         FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
       #undef FLATBUFFERS_TD
-      // clang-format on
     };
+    // clang-format on
     return ctypename[type.base_type];
   }
 

src/idl_gen_lua.cpp

@@ -595,15 +595,15 @@ class LuaGenerator : public BaseGenerator {
   }
 
   std::string GenTypeBasic(const Type &type) {
-    static const char *ctypename[] = {
     // clang-format off
+    static const char *ctypename[] = {
       #define FLATBUFFERS_TD(ENUM, IDLTYPE, \
-            CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, RTYPE, KTYPE) \
+              CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, ...) \
         #PTYPE,
         FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
       #undef FLATBUFFERS_TD
-      // clang-format on
     };
+    // clang-format on
     return ctypename[type.base_type];
   }
 

src/idl_gen_php.cpp

@@ -860,15 +860,15 @@ class PhpGenerator : public BaseGenerator {
   }
 
   static std::string GenTypeBasic(const Type &type) {
-    static const char *ctypename[] = {
     // clang-format off
+    static const char *ctypename[] = {
       #define FLATBUFFERS_TD(ENUM, IDLTYPE, \
-            CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, RTYPE, KTYPE) \
+              CTYPE, JTYPE, GTYPE, NTYPE, ...) \
         #NTYPE,
         FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
       #undef FLATBUFFERS_TD
-      // clang-format on
     };
+    // clang-format on
     return ctypename[type.base_type];
   }
 

src/idl_gen_python.cpp

@@ -667,15 +667,15 @@ class PythonGenerator : public BaseGenerator {
   }
 
   std::string GenTypeBasic(const Type &type) {
-    static const char *ctypename[] = {
     // clang-format off
+    static const char *ctypename[] = {
       #define FLATBUFFERS_TD(ENUM, IDLTYPE, \
-        CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, RTYPE, KTYPE) \
+              CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, ...) \
         #PTYPE,
         FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
       #undef FLATBUFFERS_TD
-      // clang-format on
     };
+    // clang-format on
     return ctypename[IsArray(type) ? type.VectorType().base_type
                                    : type.base_type];
   }

src/idl_gen_rust.cpp

@@ -457,12 +457,12 @@ class RustGenerator : public BaseGenerator {
     // clang-format off
     static const char * const ctypename[] = {
     #define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, \
-                           RTYPE, KTYPE) \
+                           RTYPE, ...) \
       #RTYPE,
       FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
     #undef FLATBUFFERS_TD
-      // clang-format on
     };
+    // clang-format on
 
     if (type.enum_def) { return WrapInNameSpace(*type.enum_def); }
     return ctypename[type.base_type];
@@ -476,15 +476,15 @@ class RustGenerator : public BaseGenerator {
       FLATBUFFERS_ASSERT(false && "precondition failed in GetEnumTypeForDecl");
     }
 
-    static const char *ctypename[] = {
     // clang-format off
+    static const char *ctypename[] = {
     #define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, \
-                           RTYPE, KTYPE) \
+                           RTYPE, ...) \
       #RTYPE,
       FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
     #undef FLATBUFFERS_TD
-      // clang-format on
     };
+    // clang-format on
 
     // Enums can be bools, but their Rust representation must be a u8, as used
     // in the repr attribute (#[repr(bool)] is an invalid attribute).

src/idl_gen_text.cpp

@@ -167,8 +167,7 @@ bool Print<const void *>(const void *val, Type type, int indent,
       // Call PrintVector above specifically for each element type:
       // clang-format off
       switch (vec_type.base_type) {
-        #define FLATBUFFERS_TD(ENUM, IDLTYPE, \
-          CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, RTYPE, KTYPE) \
+        #define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, ...) \
           case BASE_TYPE_ ## ENUM: \
             if (!PrintVector<CTYPE>( \
                   *reinterpret_cast<const Vector<CTYPE> *>(val), \
@@ -187,8 +186,7 @@ bool Print<const void *>(const void *val, Type type, int indent,
       // Call PrintArray above specifically for each element type:
       // clang-format off
       switch (vec_type.base_type) {
-        #define FLATBUFFERS_TD(ENUM, IDLTYPE, \
-        CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, RTYPE, KTYPE) \
+        #define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, ...) \
         case BASE_TYPE_ ## ENUM: \
           if (!PrintArray<CTYPE>( \
               *reinterpret_cast<const Array<CTYPE, 0xFFFF> *>(val), \
@@ -198,6 +196,7 @@ bool Print<const void *>(const void *val, Type type, int indent,
           } \
           break;
         FLATBUFFERS_GEN_TYPES_SCALAR(FLATBUFFERS_TD)
+        // Arrays of scalars or structs are only possible.
         FLATBUFFERS_GEN_TYPES_POINTER(FLATBUFFERS_TD)
         #undef FLATBUFFERS_TD
         case BASE_TYPE_ARRAY: FLATBUFFERS_ASSERT(0);
@@ -286,8 +285,7 @@ static bool GenStruct(const StructDef &struct_def, const Table *table,
       text += " ";
       switch (fd.value.type.base_type) {
         // clang-format off
-          #define FLATBUFFERS_TD(ENUM, IDLTYPE, \
-            CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, RTYPE, KTYPE) \
+        #define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, ...) \
           case BASE_TYPE_ ## ENUM: \
             if (!GenField<CTYPE>(fd, table, struct_def.fixed, \
                                   opts, indent + Indent(opts), _text)) { \
@@ -297,8 +295,7 @@ static bool GenStruct(const StructDef &struct_def, const Table *table,
           FLATBUFFERS_GEN_TYPES_SCALAR(FLATBUFFERS_TD)
         #undef FLATBUFFERS_TD
         // Generate drop-thru case statements for all pointer types:
-        #define FLATBUFFERS_TD(ENUM, IDLTYPE, \
-          CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, RTYPE, KTYPE) \
+        #define FLATBUFFERS_TD(ENUM, ...) \
           case BASE_TYPE_ ## ENUM:
           FLATBUFFERS_GEN_TYPES_POINTER(FLATBUFFERS_TD)
           FLATBUFFERS_GEN_TYPE_ARRAY(FLATBUFFERS_TD)

src/idl_parser.cpp

@@ -37,26 +37,22 @@ const char *FLATBUFFERS_VERSION() {
 
 const double kPi = 3.14159265358979323846;
 
-const char *const kTypeNames[] = {
 // clang-format off
-  #define FLATBUFFERS_TD(ENUM, IDLTYPE, \
-    CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, RTYPE, KTYPE) \
+const char *const kTypeNames[] = {
+  #define FLATBUFFERS_TD(ENUM, IDLTYPE, ...) \
     IDLTYPE,
     FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
   #undef FLATBUFFERS_TD
-  // clang-format on
   nullptr
 };
 
 const char kTypeSizes[] = {
-// clang-format off
-  #define FLATBUFFERS_TD(ENUM, IDLTYPE, \
-      CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, RTYPE, KTYPE) \
+  #define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, ...) \
     sizeof(CTYPE),
     FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
   #undef FLATBUFFERS_TD
-  // clang-format on
 };
+// clang-format on
 
 // The enums in the reflection schema should match the ones we use internally.
 // Compare the last element to check if these go out of sync.
@@ -222,8 +218,7 @@ static std::string TokenToString(int t) {
     #define FLATBUFFERS_TOKEN(NAME, VALUE, STRING) STRING,
       FLATBUFFERS_GEN_TOKENS(FLATBUFFERS_TOKEN)
     #undef FLATBUFFERS_TOKEN
-    #define FLATBUFFERS_TD(ENUM, IDLTYPE, \
-      CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, RTYPE, KTYPE) \
+    #define FLATBUFFERS_TD(ENUM, IDLTYPE, ...) \
       IDLTYPE,
       FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
     #undef FLATBUFFERS_TD
@@ -1179,8 +1174,7 @@ CheckedError Parser::ParseTable(const StructDef &struct_def, std::string *value,
           size == SizeOf(field_value.type.base_type)) {
         switch (field_value.type.base_type) {
           // clang-format off
-          #define FLATBUFFERS_TD(ENUM, IDLTYPE, \
-            CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, RTYPE, KTYPE) \
+          #define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, ...) \
             case BASE_TYPE_ ## ENUM: \
               builder_.Pad(field->padding); \
               if (struct_def.fixed) { \
@@ -1194,10 +1188,9 @@ CheckedError Parser::ParseTable(const StructDef &struct_def, std::string *value,
                 builder_.AddElement(field_value.offset, val, valdef); \
               } \
               break;
-            FLATBUFFERS_GEN_TYPES_SCALAR(FLATBUFFERS_TD);
+            FLATBUFFERS_GEN_TYPES_SCALAR(FLATBUFFERS_TD)
           #undef FLATBUFFERS_TD
-          #define FLATBUFFERS_TD(ENUM, IDLTYPE, \
-            CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, RTYPE, KTYPE) \
+          #define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, ...) \
             case BASE_TYPE_ ## ENUM: \
               builder_.Pad(field->padding); \
               if (IsStruct(field->value.type)) { \
@@ -1208,7 +1201,7 @@ CheckedError Parser::ParseTable(const StructDef &struct_def, std::string *value,
                 builder_.AddOffset(field_value.offset, val); \
               } \
               break;
-            FLATBUFFERS_GEN_TYPES_POINTER(FLATBUFFERS_TD);
+            FLATBUFFERS_GEN_TYPES_POINTER(FLATBUFFERS_TD)
           #undef FLATBUFFERS_TD
             case BASE_TYPE_ARRAY:
               builder_.Pad(field->padding);
@@ -1258,8 +1251,7 @@ CheckedError Parser::ParseVectorDelimiters(uoffset_t &count, F body) {
 
 static bool CompareType(const uint8_t *a, const uint8_t *b, BaseType ftype) {
   switch (ftype) {
-#define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, \
-                       RTYPE, KTYPE)                                     \
+#define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, ...) \
   case BASE_TYPE_##ENUM: return ReadScalar<CTYPE>(a) < ReadScalar<CTYPE>(b);
     FLATBUFFERS_GEN_TYPES_SCALAR(FLATBUFFERS_TD)
 #undef FLATBUFFERS_TD
@@ -1314,8 +1306,7 @@ CheckedError Parser::ParseVector(const Type &type, uoffset_t *ovalue,
     auto &val = field_stack_.back().first;
     switch (val.type.base_type) {
       // clang-format off
-      #define FLATBUFFERS_TD(ENUM, IDLTYPE, \
-        CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, RTYPE, KTYPE) \
+      #define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE,...) \
         case BASE_TYPE_ ## ENUM: \
           if (IsStruct(val.type)) SerializeStruct(*val.type.struct_def, val); \
           else { \
@@ -1429,8 +1420,7 @@ CheckedError Parser::ParseArray(Value &array) {
     auto &val = *it;
     // clang-format off
     switch (val.type.base_type) {
-      #define FLATBUFFERS_TD(ENUM, IDLTYPE, \
-        CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, RTYPE, KTYPE) \
+      #define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, ...) \
         case BASE_TYPE_ ## ENUM: \
           if (IsStruct(val.type)) { \
             SerializeStruct(builder, *val.type.struct_def, val); \
@@ -1782,14 +1772,13 @@ CheckedError Parser::ParseSingleValue(const std::string *name, Value &e,
   if (check_now && IsScalar(match_type)) {
     // clang-format off
     switch (match_type) {
-    #define FLATBUFFERS_TD(ENUM, IDLTYPE, \
-            CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, RTYPE, KTYPE) \
+    #define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, ...) \
       case BASE_TYPE_ ## ENUM: {\
           CTYPE val; \
           ECHECK(atot(e.constant.c_str(), *this, &val)); \
           SingleValueRepack(e, val); \
         break; }
-    FLATBUFFERS_GEN_TYPES_SCALAR(FLATBUFFERS_TD);
+    FLATBUFFERS_GEN_TYPES_SCALAR(FLATBUFFERS_TD)
     #undef FLATBUFFERS_TD
     default: break;
     }
@@ -2018,13 +2007,12 @@ struct EnumValBuilder {
   FLATBUFFERS_CHECKED_ERROR ValidateValue(int64_t *ev, bool next) {
     // clang-format off
     switch (enum_def.underlying_type.base_type) {
-    #define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, JTYPE, GTYPE, NTYPE,   \
-                           PTYPE, RTYPE, KTYPE)                         \
+    #define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, ...)                   \
       case BASE_TYPE_##ENUM: {                                          \
         if (!IsInteger(BASE_TYPE_##ENUM)) break;                        \
         return ValidateImpl<BASE_TYPE_##ENUM, CTYPE>(ev, next ? 1 : 0); \
       }
-      FLATBUFFERS_GEN_TYPES_SCALAR(FLATBUFFERS_TD);
+      FLATBUFFERS_GEN_TYPES_SCALAR(FLATBUFFERS_TD)
     #undef FLATBUFFERS_TD
     default: break;
     }