diff --git a/src/idl_parser.cpp b/src/idl_parser.cpp
new file mode 100644
index 0000000..31b315c
--- /dev/null
+++ b/src/idl_parser.cpp
@@ -0,0 +1,3518 @@
+/*
+ * Copyright 2014 Google Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <algorithm>
+#include <list>
+#include <string>
+#include <utility>
+
+#include <cmath>
+
+#include "flatbuffers/idl.h"
+#include "flatbuffers/util.h"
+
+namespace flatbuffers {
+
+// Reflects the version at the compiling time of binary(lib/dll/so).
+const char *FLATBUFFERS_VERSION() {
+  // clang-format off
+  return
+      FLATBUFFERS_STRING(FLATBUFFERS_VERSION_MAJOR) "."
+      FLATBUFFERS_STRING(FLATBUFFERS_VERSION_MINOR) "."
+      FLATBUFFERS_STRING(FLATBUFFERS_VERSION_REVISION);
+  // clang-format on
+}
+
+const double kPi = 3.14159265358979323846;
+
+const char *const kTypeNames[] = {
+// clang-format off
+  #define FLATBUFFERS_TD(ENUM, IDLTYPE, \
+    CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, RTYPE, KTYPE) \
+    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) \
+      sizeof(CTYPE),
+    FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
+  #undef FLATBUFFERS_TD
+  // 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.
+static_assert(BASE_TYPE_UNION == static_cast<BaseType>(reflection::Union),
+              "enums don't match");
+
+// Any parsing calls have to be wrapped in this macro, which automates
+// handling of recursive error checking a bit. It will check the received
+// CheckedError object, and return straight away on error.
+#define ECHECK(call)           \
+  {                            \
+    auto ce = (call);          \
+    if (ce.Check()) return ce; \
+  }
+
+// These two functions are called hundreds of times below, so define a short
+// form:
+#define NEXT() ECHECK(Next())
+#define EXPECT(tok) ECHECK(Expect(tok))
+
+static bool ValidateUTF8(const std::string &str) {
+  const char *s = &str[0];
+  const char *const sEnd = s + str.length();
+  while (s < sEnd) {
+    if (FromUTF8(&s) < 0) { return false; }
+  }
+  return true;
+}
+
+// Convert an underscore_based_indentifier in to camelCase.
+// Also uppercases the first character if first is true.
+std::string MakeCamel(const std::string &in, bool first) {
+  std::string s;
+  for (size_t i = 0; i < in.length(); i++) {
+    if (!i && first)
+      s += static_cast<char>(toupper(in[0]));
+    else if (in[i] == '_' && i + 1 < in.length())
+      s += static_cast<char>(toupper(in[++i]));
+    else
+      s += in[i];
+  }
+  return s;
+}
+
+void DeserializeDoc( std::vector<std::string> &doc,
+                     const Vector<Offset<String>> *documentation) {
+  if (documentation == nullptr) return;
+  for (uoffset_t index = 0; index < documentation->size(); index++)
+    doc.push_back(documentation->Get(index)->str());
+}
+
+void Parser::Message(const std::string &msg) {
+  if (!error_.empty()) error_ += "\n";  // log all warnings and errors
+  error_ += file_being_parsed_.length() ? AbsolutePath(file_being_parsed_) : "";
+  // clang-format off
+
+  #ifdef _WIN32  // MSVC alike
+    error_ +=
+        "(" + NumToString(line_) + ", " + NumToString(CursorPosition()) + ")";
+  #else  // gcc alike
+    if (file_being_parsed_.length()) error_ += ":";
+    error_ += NumToString(line_) + ": " + NumToString(CursorPosition());
+  #endif
+  // clang-format on
+  error_ += ": " + msg;
+}
+
+void Parser::Warning(const std::string &msg) { Message("warning: " + msg); }
+
+CheckedError Parser::Error(const std::string &msg) {
+  Message("error: " + msg);
+  return CheckedError(true);
+}
+
+inline CheckedError NoError() { return CheckedError(false); }
+
+CheckedError Parser::RecurseError() {
+  return Error("maximum parsing recursion of " +
+               NumToString(FLATBUFFERS_MAX_PARSING_DEPTH) + " reached");
+}
+
+template<typename F> CheckedError Parser::Recurse(F f) {
+  if (recurse_protection_counter >= (FLATBUFFERS_MAX_PARSING_DEPTH))
+    return RecurseError();
+  recurse_protection_counter++;
+  auto ce = f();
+  recurse_protection_counter--;
+  return ce;
+}
+
+template<typename T> std::string TypeToIntervalString() {
+  return "[" + NumToString((flatbuffers::numeric_limits<T>::lowest)()) + "; " +
+         NumToString((flatbuffers::numeric_limits<T>::max)()) + "]";
+}
+
+// atot: template version of atoi/atof: convert a string to an instance of T.
+template<typename T>
+inline CheckedError atot(const char *s, Parser &parser, T *val) {
+  auto done = StringToNumber(s, val);
+  if (done) return NoError();
+  if (0 == *val)
+    return parser.Error("invalid number: \"" + std::string(s) + "\"");
+  else
+    return parser.Error("invalid number: \"" + std::string(s) + "\"" +
+                        ", constant does not fit " + TypeToIntervalString<T>());
+}
+template<>
+inline CheckedError atot<Offset<void>>(const char *s, Parser &parser,
+                                       Offset<void> *val) {
+  (void)parser;
+  *val = Offset<void>(atoi(s));
+  return NoError();
+}
+
+std::string Namespace::GetFullyQualifiedName(const std::string &name,
+                                             size_t max_components) const {
+  // Early exit if we don't have a defined namespace.
+  if (components.empty() || !max_components) { return name; }
+  std::string stream_str;
+  for (size_t i = 0; i < std::min(components.size(), max_components); i++) {
+    if (i) { stream_str += '.'; }
+    stream_str += std::string(components[i]);
+  }
+  if (name.length()) {
+    stream_str += '.';
+    stream_str += name;
+  }
+  return stream_str;
+}
+
+// Declare tokens we'll use. Single character tokens are represented by their
+// ascii character code (e.g. '{'), others above 256.
+// clang-format off
+#define FLATBUFFERS_GEN_TOKENS(TD) \
+  TD(Eof, 256, "end of file") \
+  TD(StringConstant, 257, "string constant") \
+  TD(IntegerConstant, 258, "integer constant") \
+  TD(FloatConstant, 259, "float constant") \
+  TD(Identifier, 260, "identifier")
+#ifdef __GNUC__
+__extension__  // Stop GCC complaining about trailing comma with -Wpendantic.
+#endif
+enum {
+  #define FLATBUFFERS_TOKEN(NAME, VALUE, STRING) kToken ## NAME = VALUE,
+    FLATBUFFERS_GEN_TOKENS(FLATBUFFERS_TOKEN)
+  #undef FLATBUFFERS_TOKEN
+};
+
+static std::string TokenToString(int t) {
+  static const char * const tokens[] = {
+    #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) \
+      IDLTYPE,
+      FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
+    #undef FLATBUFFERS_TD
+  };
+  if (t < 256) {  // A single ascii char token.
+    std::string s;
+    s.append(1, static_cast<char>(t));
+    return s;
+  } else {       // Other tokens.
+    return tokens[t - 256];
+  }
+}
+// clang-format on
+
+std::string Parser::TokenToStringId(int t) const {
+  return t == kTokenIdentifier ? attribute_ : TokenToString(t);
+}
+
+// Parses exactly nibbles worth of hex digits into a number, or error.
+CheckedError Parser::ParseHexNum(int nibbles, uint64_t *val) {
+  FLATBUFFERS_ASSERT(nibbles > 0);
+  for (int i = 0; i < nibbles; i++)
+    if (!is_xdigit(cursor_[i]))
+      return Error("escape code must be followed by " + NumToString(nibbles) +
+                   " hex digits");
+  std::string target(cursor_, cursor_ + nibbles);
+  *val = StringToUInt(target.c_str(), 16);
+  cursor_ += nibbles;
+  return NoError();
+}
+
+CheckedError Parser::SkipByteOrderMark() {
+  if (static_cast<unsigned char>(*cursor_) != 0xef) return NoError();
+  cursor_++;
+  if (static_cast<unsigned char>(*cursor_) != 0xbb)
+    return Error("invalid utf-8 byte order mark");
+  cursor_++;
+  if (static_cast<unsigned char>(*cursor_) != 0xbf)
+    return Error("invalid utf-8 byte order mark");
+  cursor_++;
+  return NoError();
+}
+
+static inline bool IsIdentifierStart(char c) {
+  return is_alpha(c) || (c == '_');
+}
+
+CheckedError Parser::Next() {
+  doc_comment_.clear();
+  bool seen_newline = cursor_ == source_;
+  attribute_.clear();
+  attr_is_trivial_ascii_string_ = true;
+  for (;;) {
+    char c = *cursor_++;
+    token_ = c;
+    switch (c) {
+      case '\0':
+        cursor_--;
+        token_ = kTokenEof;
+        return NoError();
+      case ' ':
+      case '\r':
+      case '\t': break;
+      case '\n':
+        MarkNewLine();
+        seen_newline = true;
+        break;
+      case '{':
+      case '}':
+      case '(':
+      case ')':
+      case '[':
+      case ']':
+      case ',':
+      case ':':
+      case ';':
+      case '=': return NoError();
+      case '\"':
+      case '\'': {
+        int unicode_high_surrogate = -1;
+
+        while (*cursor_ != c) {
+          if (*cursor_ < ' ' && static_cast<signed char>(*cursor_) >= 0)
+            return Error("illegal character in string constant");
+          if (*cursor_ == '\\') {
+            attr_is_trivial_ascii_string_ = false;  // has escape sequence
+            cursor_++;
+            if (unicode_high_surrogate != -1 && *cursor_ != 'u') {
+              return Error(
+                  "illegal Unicode sequence (unpaired high surrogate)");
+            }
+            switch (*cursor_) {
+              case 'n':
+                attribute_ += '\n';
+                cursor_++;
+                break;
+              case 't':
+                attribute_ += '\t';
+                cursor_++;
+                break;
+              case 'r':
+                attribute_ += '\r';
+                cursor_++;
+                break;
+              case 'b':
+                attribute_ += '\b';
+                cursor_++;
+                break;
+              case 'f':
+                attribute_ += '\f';
+                cursor_++;
+                break;
+              case '\"':
+                attribute_ += '\"';
+                cursor_++;
+                break;
+              case '\'':
+                attribute_ += '\'';
+                cursor_++;
+                break;
+              case '\\':
+                attribute_ += '\\';
+                cursor_++;
+                break;
+              case '/':
+                attribute_ += '/';
+                cursor_++;
+                break;
+              case 'x': {  // Not in the JSON standard
+                cursor_++;
+                uint64_t val;
+                ECHECK(ParseHexNum(2, &val));
+                attribute_ += static_cast<char>(val);
+                break;
+              }
+              case 'u': {
+                cursor_++;
+                uint64_t val;
+                ECHECK(ParseHexNum(4, &val));
+                if (val >= 0xD800 && val <= 0xDBFF) {
+                  if (unicode_high_surrogate != -1) {
+                    return Error(
+                        "illegal Unicode sequence (multiple high surrogates)");
+                  } else {
+                    unicode_high_surrogate = static_cast<int>(val);
+                  }
+                } else if (val >= 0xDC00 && val <= 0xDFFF) {
+                  if (unicode_high_surrogate == -1) {
+                    return Error(
+                        "illegal Unicode sequence (unpaired low surrogate)");
+                  } else {
+                    int code_point = 0x10000 +
+                                     ((unicode_high_surrogate & 0x03FF) << 10) +
+                                     (val & 0x03FF);
+                    ToUTF8(code_point, &attribute_);
+                    unicode_high_surrogate = -1;
+                  }
+                } else {
+                  if (unicode_high_surrogate != -1) {
+                    return Error(
+                        "illegal Unicode sequence (unpaired high surrogate)");
+                  }
+                  ToUTF8(static_cast<int>(val), &attribute_);
+                }
+                break;
+              }
+              default: return Error("unknown escape code in string constant");
+            }
+          } else {  // printable chars + UTF-8 bytes
+            if (unicode_high_surrogate != -1) {
+              return Error(
+                  "illegal Unicode sequence (unpaired high surrogate)");
+            }
+            // reset if non-printable
+            attr_is_trivial_ascii_string_ &= check_ascii_range(*cursor_, ' ', '~');
+
+            attribute_ += *cursor_++;
+          }
+        }
+        if (unicode_high_surrogate != -1) {
+          return Error("illegal Unicode sequence (unpaired high surrogate)");
+        }
+        cursor_++;
+        if (!attr_is_trivial_ascii_string_ && !opts.allow_non_utf8 &&
+            !ValidateUTF8(attribute_)) {
+          return Error("illegal UTF-8 sequence");
+        }
+        token_ = kTokenStringConstant;
+        return NoError();
+      }
+      case '/':
+        if (*cursor_ == '/') {
+          const char *start = ++cursor_;
+          while (*cursor_ && *cursor_ != '\n' && *cursor_ != '\r') cursor_++;
+          if (*start == '/') {  // documentation comment
+            if (!seen_newline)
+              return Error(
+                  "a documentation comment should be on a line on its own");
+            doc_comment_.push_back(std::string(start + 1, cursor_));
+          }
+          break;
+        } else if (*cursor_ == '*') {
+          cursor_++;
+          // TODO: make nested.
+          while (*cursor_ != '*' || cursor_[1] != '/') {
+            if (*cursor_ == '\n') MarkNewLine();
+            if (!*cursor_) return Error("end of file in comment");
+            cursor_++;
+          }
+          cursor_ += 2;
+          break;
+        }
+        FLATBUFFERS_FALLTHROUGH(); // else fall thru
+      default:
+        const auto has_sign = (c == '+') || (c == '-');
+        // '-'/'+' and following identifier - can be a predefined constant like:
+        // NAN, INF, PI, etc.
+        if (IsIdentifierStart(c) || (has_sign && IsIdentifierStart(*cursor_))) {
+          // Collect all chars of an identifier:
+          const char *start = cursor_ - 1;
+          while (IsIdentifierStart(*cursor_) || is_digit(*cursor_)) cursor_++;
+          attribute_.append(start, cursor_);
+          token_ = has_sign ? kTokenStringConstant : kTokenIdentifier;
+          return NoError();
+        }
+
+        auto dot_lvl = (c == '.') ? 0 : 1;  // dot_lvl==0 <=> exactly one '.' seen
+        if (!dot_lvl && !is_digit(*cursor_)) return NoError(); // enum?
+        // Parser accepts hexadecimal-floating-literal (see C++ 5.13.4).
+        if (is_digit(c) || has_sign || !dot_lvl) {
+          const auto start = cursor_ - 1;
+          auto start_digits = !is_digit(c) ? cursor_ : cursor_ - 1;
+          if (!is_digit(c) && is_digit(*cursor_)){
+            start_digits = cursor_; // see digit in cursor_ position
+            c = *cursor_++;
+          }
+          // hex-float can't begind with '.'
+          auto use_hex = dot_lvl && (c == '0') && is_alpha_char(*cursor_, 'X');
+          if (use_hex) start_digits = ++cursor_;  // '0x' is the prefix, skip it
+          // Read an integer number or mantisa of float-point number.
+          do {
+            if (use_hex) {
+              while (is_xdigit(*cursor_)) cursor_++;
+            } else {
+              while (is_digit(*cursor_)) cursor_++;
+            }
+          } while ((*cursor_ == '.') && (++cursor_) && (--dot_lvl >= 0));
+          // Exponent of float-point number.
+          if ((dot_lvl >= 0) && (cursor_ > start_digits)) {
+            // The exponent suffix of hexadecimal float number is mandatory.
+            if (use_hex && !dot_lvl) start_digits = cursor_;
+            if ((use_hex && is_alpha_char(*cursor_, 'P')) ||
+                is_alpha_char(*cursor_, 'E')) {
+              dot_lvl = 0;  // Emulate dot to signal about float-point number.
+              cursor_++;
+              if (*cursor_ == '+' || *cursor_ == '-') cursor_++;
+              start_digits = cursor_;  // the exponent-part has to have digits
+              // Exponent is decimal integer number
+              while (is_digit(*cursor_)) cursor_++;
+              if (*cursor_ == '.') {
+                cursor_++;  // If see a dot treat it as part of invalid number.
+                dot_lvl = -1;  // Fall thru to Error().
+              }
+            }
+          }
+          // Finalize.
+          if ((dot_lvl >= 0) && (cursor_ > start_digits)) {
+            attribute_.append(start, cursor_);
+            token_ = dot_lvl ? kTokenIntegerConstant : kTokenFloatConstant;
+            return NoError();
+          } else {
+            return Error("invalid number: " + std::string(start, cursor_));
+          }
+        }
+        std::string ch;
+        ch = c;
+        if (false == check_ascii_range(c, ' ', '~')) ch = "code: " + NumToString(c);
+        return Error("illegal character: " + ch);
+    }
+  }
+}
+
+// Check if a given token is next.
+bool Parser::Is(int t) const { return t == token_; }
+
+bool Parser::IsIdent(const char *id) const {
+  return token_ == kTokenIdentifier && attribute_ == id;
+}
+
+// Expect a given token to be next, consume it, or error if not present.
+CheckedError Parser::Expect(int t) {
+  if (t != token_) {
+    return Error("expecting: " + TokenToString(t) +
+                 " instead got: " + TokenToStringId(token_));
+  }
+  NEXT();
+  return NoError();
+}
+
+CheckedError Parser::ParseNamespacing(std::string *id, std::string *last) {
+  while (Is('.')) {
+    NEXT();
+    *id += ".";
+    *id += attribute_;
+    if (last) *last = attribute_;
+    EXPECT(kTokenIdentifier);
+  }
+  return NoError();
+}
+
+EnumDef *Parser::LookupEnum(const std::string &id) {
+  // Search thru parent namespaces.
+  for (int components = static_cast<int>(current_namespace_->components.size());
+       components >= 0; components--) {
+    auto ed = enums_.Lookup(
+        current_namespace_->GetFullyQualifiedName(id, components));
+    if (ed) return ed;
+  }
+  return nullptr;
+}
+
+StructDef *Parser::LookupStruct(const std::string &id) const {
+  auto sd = structs_.Lookup(id);
+  if (sd) sd->refcount++;
+  return sd;
+}
+
+CheckedError Parser::ParseTypeIdent(Type &type) {
+  std::string id = attribute_;
+  EXPECT(kTokenIdentifier);
+  ECHECK(ParseNamespacing(&id, nullptr));
+  auto enum_def = LookupEnum(id);
+  if (enum_def) {
+    type = enum_def->underlying_type;
+    if (enum_def->is_union) type.base_type = BASE_TYPE_UNION;
+  } else {
+    type.base_type = BASE_TYPE_STRUCT;
+    type.struct_def = LookupCreateStruct(id);
+  }
+  return NoError();
+}
+
+// Parse any IDL type.
+CheckedError Parser::ParseType(Type &type) {
+  if (token_ == kTokenIdentifier) {
+    if (IsIdent("bool")) {
+      type.base_type = BASE_TYPE_BOOL;
+      NEXT();
+    } else if (IsIdent("byte") || IsIdent("int8")) {
+      type.base_type = BASE_TYPE_CHAR;
+      NEXT();
+    } else if (IsIdent("ubyte") || IsIdent("uint8")) {
+      type.base_type = BASE_TYPE_UCHAR;
+      NEXT();
+    } else if (IsIdent("short") || IsIdent("int16")) {
+      type.base_type = BASE_TYPE_SHORT;
+      NEXT();
+    } else if (IsIdent("ushort") || IsIdent("uint16")) {
+      type.base_type = BASE_TYPE_USHORT;
+      NEXT();
+    } else if (IsIdent("int") || IsIdent("int32")) {
+      type.base_type = BASE_TYPE_INT;
+      NEXT();
+    } else if (IsIdent("uint") || IsIdent("uint32")) {
+      type.base_type = BASE_TYPE_UINT;
+      NEXT();
+    } else if (IsIdent("long") || IsIdent("int64")) {
+      type.base_type = BASE_TYPE_LONG;
+      NEXT();
+    } else if (IsIdent("ulong") || IsIdent("uint64")) {
+      type.base_type = BASE_TYPE_ULONG;
+      NEXT();
+    } else if (IsIdent("float") || IsIdent("float32")) {
+      type.base_type = BASE_TYPE_FLOAT;
+      NEXT();
+    } else if (IsIdent("double") || IsIdent("float64")) {
+      type.base_type = BASE_TYPE_DOUBLE;
+      NEXT();
+    } else if (IsIdent("string")) {
+      type.base_type = BASE_TYPE_STRING;
+      NEXT();
+    } else {
+      ECHECK(ParseTypeIdent(type));
+    }
+  } else if (token_ == '[') {
+    NEXT();
+    Type subtype;
+    ECHECK(Recurse([&]() { return ParseType(subtype); }));
+    if (IsSeries(subtype)) {
+      // We could support this, but it will complicate things, and it's
+      // easier to work around with a struct around the inner vector.
+      return Error("nested vector types not supported (wrap in table first)");
+    }
+    if (token_ == ':') {
+      NEXT();
+      if (token_ != kTokenIntegerConstant) {
+        return Error("length of fixed-length array must be an integer value");
+      }
+      uint16_t fixed_length = 0;
+      bool check = StringToNumber(attribute_.c_str(), &fixed_length);
+      if (!check || fixed_length < 1) {
+        return Error(
+            "length of fixed-length array must be positive and fit to "
+            "uint16_t type");
+      }
+      // Check if enum arrays are used in C++ without specifying --scoped-enums
+      if ((opts.lang_to_generate & IDLOptions::kCpp) && !opts.scoped_enums &&
+          IsEnum(subtype)) {
+        return Error(
+            "--scoped-enums must be enabled to use enum arrays in C++\n");
+      }
+      type = Type(BASE_TYPE_ARRAY, subtype.struct_def, subtype.enum_def,
+                  fixed_length);
+      NEXT();
+    } else {
+      type = Type(BASE_TYPE_VECTOR, subtype.struct_def, subtype.enum_def);
+    }
+    type.element = subtype.base_type;
+    EXPECT(']');
+  } else {
+    return Error("illegal type syntax");
+  }
+  return NoError();
+}
+
+CheckedError Parser::AddField(StructDef &struct_def, const std::string &name,
+                              const Type &type, FieldDef **dest) {
+  auto &field = *new FieldDef();
+  field.value.offset =
+      FieldIndexToOffset(static_cast<voffset_t>(struct_def.fields.vec.size()));
+  field.name = name;
+  field.file = struct_def.file;
+  field.value.type = type;
+  if (struct_def.fixed) {  // statically compute the field offset
+    auto size = InlineSize(type);
+    auto alignment = InlineAlignment(type);
+    // structs_ need to have a predictable format, so we need to align to
+    // the largest scalar
+    struct_def.minalign = std::max(struct_def.minalign, alignment);
+    struct_def.PadLastField(alignment);
+    field.value.offset = static_cast<voffset_t>(struct_def.bytesize);
+    struct_def.bytesize += size;
+  }
+  if (struct_def.fields.Add(name, &field))
+    return Error("field already exists: " + name);
+  *dest = &field;
+  return NoError();
+}
+
+CheckedError Parser::ParseField(StructDef &struct_def) {
+  std::string name = attribute_;
+
+  if (LookupStruct(name))
+    return Error("field name can not be the same as table/struct name");
+
+  std::vector<std::string> dc = doc_comment_;
+  EXPECT(kTokenIdentifier);
+  EXPECT(':');
+  Type type;
+  ECHECK(ParseType(type));
+
+  if (struct_def.fixed && !IsScalar(type.base_type) && !IsStruct(type) &&
+      !IsArray(type))
+    return Error("structs_ may contain only scalar or struct fields");
+
+  if (!struct_def.fixed && IsArray(type))
+    return Error("fixed-length array in table must be wrapped in struct");
+
+  if (IsArray(type) && !SupportsAdvancedArrayFeatures()) {
+    return Error(
+        "Arrays are not yet supported in all "
+        "the specified programming languages.");
+  }
+
+  FieldDef *typefield = nullptr;
+  if (type.base_type == BASE_TYPE_UNION) {
+    // For union fields, add a second auto-generated field to hold the type,
+    // with a special suffix.
+    ECHECK(AddField(struct_def, name + UnionTypeFieldSuffix(),
+                    type.enum_def->underlying_type, &typefield));
+  } else if (type.base_type == BASE_TYPE_VECTOR &&
+             type.element == BASE_TYPE_UNION) {
+    // Only cpp, js and ts supports the union vector feature so far.
+    if (!SupportsAdvancedUnionFeatures()) {
+      return Error(
+          "Vectors of unions are not yet supported in all "
+          "the specified programming languages.");
+    }
+    // For vector of union fields, add a second auto-generated vector field to
+    // hold the types, with a special suffix.
+    Type union_vector(BASE_TYPE_VECTOR, nullptr, type.enum_def);
+    union_vector.element = BASE_TYPE_UTYPE;
+    ECHECK(AddField(struct_def, name + UnionTypeFieldSuffix(), union_vector,
+                    &typefield));
+  }
+
+  FieldDef *field;
+  ECHECK(AddField(struct_def, name, type, &field));
+
+  if (token_ == '=') {
+    NEXT();
+    ECHECK(ParseSingleValue(&field->name, field->value, true));
+    if (!IsScalar(type.base_type) ||
+        (struct_def.fixed && field->value.constant != "0"))
+      return Error(
+            "default values currently only supported for scalars in tables");
+  }
+  // Append .0 if the value has not it (skip hex and scientific floats).
+  // This suffix needed for generated C++ code.
+  if (IsFloat(type.base_type)) {
+    auto &text = field->value.constant;
+    FLATBUFFERS_ASSERT(false == text.empty());
+    auto s = text.c_str();
+    while(*s == ' ') s++;
+    if (*s == '-' || *s == '+') s++;
+    // 1) A float constants (nan, inf, pi, etc) is a kind of identifier.
+    // 2) A float number needn't ".0" at the end if it has exponent.
+    if ((false == IsIdentifierStart(*s)) &&
+        (std::string::npos == field->value.constant.find_first_of(".eEpP"))) {
+      field->value.constant += ".0";
+    }
+  }
+  if (type.enum_def) {
+    // The type.base_type can only be scalar, union, array or vector.
+    // Table, struct or string can't have enum_def.
+    // Default value of union and vector in NONE, NULL translated to "0".
+    FLATBUFFERS_ASSERT(IsInteger(type.base_type) ||
+                       (type.base_type == BASE_TYPE_UNION) ||
+                       (type.base_type == BASE_TYPE_VECTOR) ||
+                       (type.base_type == BASE_TYPE_ARRAY));
+    if (type.base_type == BASE_TYPE_VECTOR) {
+      // Vector can't use initialization list.
+      FLATBUFFERS_ASSERT(field->value.constant == "0");
+    } else {
+      // All unions should have the NONE ("0") enum value.
+      auto in_enum = type.enum_def->attributes.Lookup("bit_flags") ||
+                     type.enum_def->FindByValue(field->value.constant);
+      if (false == in_enum)
+        return Error("default value of " + field->value.constant +
+                     " for field " + name + " is not part of enum " +
+                     type.enum_def->name);
+    }
+  }
+
+  field->doc_comment = dc;
+  ECHECK(ParseMetaData(&field->attributes));
+  field->deprecated = field->attributes.Lookup("deprecated") != nullptr;
+  auto hash_name = field->attributes.Lookup("hash");
+  if (hash_name) {
+    switch ((type.base_type == BASE_TYPE_VECTOR) ? type.element : type.base_type) {
+      case BASE_TYPE_SHORT:
+      case BASE_TYPE_USHORT: {
+        if (FindHashFunction16(hash_name->constant.c_str()) == nullptr)
+          return Error("Unknown hashing algorithm for 16 bit types: " +
+                       hash_name->constant);
+        break;
+      }
+      case BASE_TYPE_INT:
+      case BASE_TYPE_UINT: {
+        if (FindHashFunction32(hash_name->constant.c_str()) == nullptr)
+          return Error("Unknown hashing algorithm for 32 bit types: " +
+                       hash_name->constant);
+        break;
+      }
+      case BASE_TYPE_LONG:
+      case BASE_TYPE_ULONG: {
+        if (FindHashFunction64(hash_name->constant.c_str()) == nullptr)
+          return Error("Unknown hashing algorithm for 64 bit types: " +
+                       hash_name->constant);
+        break;
+      }
+      default:
+        return Error(
+            "only short, ushort, int, uint, long and ulong data types support hashing.");
+    }
+  }
+  auto cpp_type = field->attributes.Lookup("cpp_type");
+  if (cpp_type) {
+    if (!hash_name)
+      return Error("cpp_type can only be used with a hashed field");
+    /// forcing cpp_ptr_type to 'naked' if unset
+    auto cpp_ptr_type = field->attributes.Lookup("cpp_ptr_type");
+    if (!cpp_ptr_type) {
+      auto val = new Value();
+      val->type = cpp_type->type;
+      val->constant = "naked";
+      field->attributes.Add("cpp_ptr_type", val);
+    }
+  }
+  if (field->deprecated && struct_def.fixed)
+    return Error("can't deprecate fields in a struct");
+  field->required = field->attributes.Lookup("required") != nullptr;
+  if (field->required &&
+      (struct_def.fixed || IsScalar(type.base_type)))
+    return Error("only non-scalar fields in tables may be 'required'");
+  field->key = field->attributes.Lookup("key") != nullptr;
+  if (field->key) {
+    if (struct_def.has_key) return Error("only one field may be set as 'key'");
+    struct_def.has_key = true;
+    if (!IsScalar(type.base_type)) {
+      field->required = true;
+      if (type.base_type != BASE_TYPE_STRING)
+        return Error("'key' field must be string or scalar type");
+    }
+  }
+  field->shared = field->attributes.Lookup("shared") != nullptr;
+  if (field->shared && field->value.type.base_type != BASE_TYPE_STRING)
+    return Error("shared can only be defined on strings");
+
+  auto field_native_custom_alloc =
+      field->attributes.Lookup("native_custom_alloc");
+  if (field_native_custom_alloc)
+    return Error(
+        "native_custom_alloc can only be used with a table or struct "
+        "definition");
+
+  field->native_inline = field->attributes.Lookup("native_inline") != nullptr;
+  if (field->native_inline && !IsStruct(field->value.type))
+    return Error("native_inline can only be defined on structs");
+
+  auto nested = field->attributes.Lookup("nested_flatbuffer");
+  if (nested) {
+    if (nested->type.base_type != BASE_TYPE_STRING)
+      return Error(
+          "nested_flatbuffer attribute must be a string (the root type)");
+    if (type.base_type != BASE_TYPE_VECTOR || type.element != BASE_TYPE_UCHAR)
+      return Error(
+          "nested_flatbuffer attribute may only apply to a vector of ubyte");
+    // This will cause an error if the root type of the nested flatbuffer
+    // wasn't defined elsewhere.
+    field->nested_flatbuffer = LookupCreateStruct(nested->constant);
+  }
+
+  if (field->attributes.Lookup("flexbuffer")) {
+    field->flexbuffer = true;
+    uses_flexbuffers_ = true;
+    if (type.base_type != BASE_TYPE_VECTOR ||
+        type.element != BASE_TYPE_UCHAR)
+      return Error("flexbuffer attribute may only apply to a vector of ubyte");
+  }
+
+  if (typefield) {
+    if (!IsScalar(typefield->value.type.base_type)) {
+      // this is a union vector field
+      typefield->required = field->required;
+    }
+    // If this field is a union, and it has a manually assigned id,
+    // the automatically added type field should have an id as well (of N - 1).
+    auto attr = field->attributes.Lookup("id");
+    if (attr) {
+      auto id = atoi(attr->constant.c_str());
+      auto val = new Value();
+      val->type = attr->type;
+      val->constant = NumToString(id - 1);
+      typefield->attributes.Add("id", val);
+    }
+  }
+
+  EXPECT(';');
+  return NoError();
+}
+
+CheckedError Parser::ParseString(Value &val) {
+  auto s = attribute_;
+  EXPECT(kTokenStringConstant);
+  val.constant = NumToString(builder_.CreateString(s).o);
+  return NoError();
+}
+
+CheckedError Parser::ParseComma() {
+  if (!opts.protobuf_ascii_alike) EXPECT(',');
+  return NoError();
+}
+
+CheckedError Parser::ParseAnyValue(Value &val, FieldDef *field,
+                                   size_t parent_fieldn,
+                                   const StructDef *parent_struct_def,
+                                   uoffset_t count,
+                                   bool inside_vector) {
+  switch (val.type.base_type) {
+    case BASE_TYPE_UNION: {
+      FLATBUFFERS_ASSERT(field);
+      std::string constant;
+      Vector<uint8_t> *vector_of_union_types = nullptr;
+      // Find corresponding type field we may have already parsed.
+      for (auto elem = field_stack_.rbegin() + count;
+           elem != field_stack_.rbegin() + parent_fieldn + count; ++elem) {
+        auto &type = elem->second->value.type;
+        if (type.enum_def == val.type.enum_def) {
+          if (inside_vector) {
+            if (type.base_type == BASE_TYPE_VECTOR &&
+                type.element == BASE_TYPE_UTYPE) {
+              // Vector of union type field.
+              uoffset_t offset;
+              ECHECK(atot(elem->first.constant.c_str(), *this, &offset));
+              vector_of_union_types = reinterpret_cast<Vector<uint8_t> *>(
+                                        builder_.GetCurrentBufferPointer() +
+                                        builder_.GetSize() - offset);
+              break;
+            }
+          } else {
+            if (type.base_type == BASE_TYPE_UTYPE) {
+              // Union type field.
+              constant = elem->first.constant;
+              break;
+            }
+          }
+        }
+      }
+      if (constant.empty() && !inside_vector) {
+        // We haven't seen the type field yet. Sadly a lot of JSON writers
+        // output these in alphabetical order, meaning it comes after this
+        // value. So we scan past the value to find it, then come back here.
+        // We currently don't do this for vectors of unions because the
+        // scanning/serialization logic would get very complicated.
+        auto type_name = field->name + UnionTypeFieldSuffix();
+        FLATBUFFERS_ASSERT(parent_struct_def);
+        auto type_field = parent_struct_def->fields.Lookup(type_name);
+        FLATBUFFERS_ASSERT(type_field);  // Guaranteed by ParseField().
+        // Remember where we are in the source file, so we can come back here.
+        auto backup = *static_cast<ParserState *>(this);
+        ECHECK(SkipAnyJsonValue());  // The table.
+        ECHECK(ParseComma());
+        auto next_name = attribute_;
+        if (Is(kTokenStringConstant)) {
+          NEXT();
+        } else {
+          EXPECT(kTokenIdentifier);
+        }
+        if (next_name == type_name) {
+          EXPECT(':');
+          Value type_val = type_field->value;
+          ECHECK(ParseAnyValue(type_val, type_field, 0, nullptr, 0));
+          constant = type_val.constant;
+          // Got the information we needed, now rewind:
+          *static_cast<ParserState *>(this) = backup;
+        }
+      }
+      if (constant.empty() && !vector_of_union_types) {
+        return Error("missing type field for this union value: " +
+                     field->name);
+      }
+      uint8_t enum_idx;
+      if (vector_of_union_types) {
+        enum_idx = vector_of_union_types->Get(count);
+      } else {
+        ECHECK(atot(constant.c_str(), *this, &enum_idx));
+      }
+      auto enum_val = val.type.enum_def->ReverseLookup(enum_idx, true);
+      if (!enum_val) return Error("illegal type id for: " + field->name);
+      if (enum_val->union_type.base_type == BASE_TYPE_STRUCT) {
+        ECHECK(ParseTable(*enum_val->union_type.struct_def, &val.constant,
+                          nullptr));
+        if (enum_val->union_type.struct_def->fixed) {
+          // All BASE_TYPE_UNION values are offsets, so turn this into one.
+          SerializeStruct(*enum_val->union_type.struct_def, val);
+          builder_.ClearOffsets();
+          val.constant = NumToString(builder_.GetSize());
+        }
+      } else if (enum_val->union_type.base_type == BASE_TYPE_STRING) {
+        ECHECK(ParseString(val));
+      } else {
+        FLATBUFFERS_ASSERT(false);
+      }
+      break;
+    }
+    case BASE_TYPE_STRUCT:
+      ECHECK(ParseTable(*val.type.struct_def, &val.constant, nullptr));
+      break;
+    case BASE_TYPE_STRING: {
+      ECHECK(ParseString(val));
+      break;
+    }
+    case BASE_TYPE_VECTOR: {
+      uoffset_t off;
+      ECHECK(ParseVector(val.type.VectorType(), &off, field, parent_fieldn));
+      val.constant = NumToString(off);
+      break;
+    }
+    case BASE_TYPE_ARRAY: {
+      ECHECK(ParseArray(val));
+      break;
+    }
+    case BASE_TYPE_INT:
+    case BASE_TYPE_UINT:
+    case BASE_TYPE_LONG:
+    case BASE_TYPE_ULONG: {
+      if (field && field->attributes.Lookup("hash") &&
+          (token_ == kTokenIdentifier || token_ == kTokenStringConstant)) {
+        ECHECK(ParseHash(val, field));
+      } else {
+        ECHECK(ParseSingleValue(field ? &field->name : nullptr, val, false));
+      }
+      break;
+    }
+    default:
+      ECHECK(ParseSingleValue(field ? &field->name : nullptr, val, false));
+      break;
+  }
+  return NoError();
+}
+
+void Parser::SerializeStruct(const StructDef &struct_def, const Value &val) {
+  SerializeStruct(builder_, struct_def, val);
+}
+
+void Parser::SerializeStruct(FlatBufferBuilder &builder,
+                             const StructDef &struct_def, const Value &val) {
+  FLATBUFFERS_ASSERT(val.constant.length() == struct_def.bytesize);
+  builder.Align(struct_def.minalign);
+  builder.PushBytes(reinterpret_cast<const uint8_t *>(val.constant.c_str()),
+                    struct_def.bytesize);
+  builder.AddStructOffset(val.offset, builder.GetSize());
+}
+
+template <typename F>
+CheckedError Parser::ParseTableDelimiters(size_t &fieldn,
+                                          const StructDef *struct_def,
+                                          F body) {
+  // We allow tables both as JSON object{ .. } with field names
+  // or vector[..] with all fields in order
+  char terminator = '}';
+  bool is_nested_vector = struct_def && Is('[');
+  if (is_nested_vector) {
+    NEXT();
+    terminator = ']';
+  } else {
+    EXPECT('{');
+  }
+  for (;;) {
+    if ((!opts.strict_json || !fieldn) && Is(terminator)) break;
+    std::string name;
+    if (is_nested_vector) {
+      if (fieldn >= struct_def->fields.vec.size()) {
+        return Error("too many unnamed fields in nested array");
+      }
+      name = struct_def->fields.vec[fieldn]->name;
+    } else {
+      name = attribute_;
+      if (Is(kTokenStringConstant)) {
+        NEXT();
+      } else {
+        EXPECT(opts.strict_json ? kTokenStringConstant : kTokenIdentifier);
+      }
+      if (!opts.protobuf_ascii_alike || !(Is('{') || Is('['))) EXPECT(':');
+    }
+    ECHECK(body(name, fieldn, struct_def));
+    if (Is(terminator)) break;
+    ECHECK(ParseComma());
+  }
+  NEXT();
+  if (is_nested_vector && fieldn != struct_def->fields.vec.size()) {
+    return Error("wrong number of unnamed fields in table vector");
+  }
+  return NoError();
+}
+
+CheckedError Parser::ParseTable(const StructDef &struct_def, std::string *value,
+                                uoffset_t *ovalue) {
+  size_t fieldn_outer = 0;
+  auto err = ParseTableDelimiters(
+      fieldn_outer, &struct_def,
+      [&](const std::string &name, size_t &fieldn,
+          const StructDef *struct_def_inner) -> CheckedError {
+        if (name == "$schema") {
+          ECHECK(Expect(kTokenStringConstant));
+          return NoError();
+        }
+        auto field = struct_def_inner->fields.Lookup(name);
+        if (!field) {
+          if (!opts.skip_unexpected_fields_in_json) {
+            return Error("unknown field: " + name);
+          } else {
+            ECHECK(SkipAnyJsonValue());
+          }
+        } else {
+          if (IsIdent("null") && !IsScalar(field->value.type.base_type)) {
+            ECHECK(Next());  // Ignore this field.
+          } else {
+            Value val = field->value;
+            if (field->flexbuffer) {
+              flexbuffers::Builder builder(1024,
+                                           flexbuffers::BUILDER_FLAG_SHARE_ALL);
+              ECHECK(ParseFlexBufferValue(&builder));
+              builder.Finish();
+              // Force alignment for nested flexbuffer
+              builder_.ForceVectorAlignment(builder.GetSize(), sizeof(uint8_t),
+                                            sizeof(largest_scalar_t));
+              auto off = builder_.CreateVector(builder.GetBuffer());
+              val.constant = NumToString(off.o);
+            } else if (field->nested_flatbuffer) {
+              ECHECK(
+                  ParseNestedFlatbuffer(val, field, fieldn, struct_def_inner));
+            } else {
+              ECHECK(Recurse([&]() {
+                return ParseAnyValue(val, field, fieldn, struct_def_inner, 0);
+              }));
+            }
+            // Hardcoded insertion-sort with error-check.
+            // If fields are specified in order, then this loop exits
+            // immediately.
+            auto elem = field_stack_.rbegin();
+            for (; elem != field_stack_.rbegin() + fieldn; ++elem) {
+              auto existing_field = elem->second;
+              if (existing_field == field)
+                return Error("field set more than once: " + field->name);
+              if (existing_field->value.offset < field->value.offset) break;
+            }
+            // Note: elem points to before the insertion point, thus .base()
+            // points to the correct spot.
+            field_stack_.insert(elem.base(), std::make_pair(val, field));
+            fieldn++;
+          }
+        }
+        return NoError();
+      });
+  ECHECK(err);
+
+  // Check if all required fields are parsed.
+  for (auto field_it = struct_def.fields.vec.begin();
+       field_it != struct_def.fields.vec.end(); ++field_it) {
+    auto required_field = *field_it;
+    if (!required_field->required) { continue; }
+    bool found = false;
+    for (auto pf_it = field_stack_.end() - fieldn_outer;
+         pf_it != field_stack_.end(); ++pf_it) {
+      auto parsed_field = pf_it->second;
+      if (parsed_field == required_field) {
+        found = true;
+        break;
+      }
+    }
+    if (!found) {
+      return Error("required field is missing: " + required_field->name +
+                   " in " + struct_def.name);
+    }
+  }
+
+  if (struct_def.fixed && fieldn_outer != struct_def.fields.vec.size())
+    return Error("struct: wrong number of initializers: " + struct_def.name);
+
+  auto start = struct_def.fixed ? builder_.StartStruct(struct_def.minalign)
+                                : builder_.StartTable();
+
+  for (size_t size = struct_def.sortbysize ? sizeof(largest_scalar_t) : 1; size;
+       size /= 2) {
+    // Go through elements in reverse, since we're building the data backwards.
+    for (auto it = field_stack_.rbegin();
+         it != field_stack_.rbegin() + fieldn_outer; ++it) {
+      auto &field_value = it->first;
+      auto field = it->second;
+      if (!struct_def.sortbysize ||
+          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) \
+            case BASE_TYPE_ ## ENUM: \
+              builder_.Pad(field->padding); \
+              if (struct_def.fixed) { \
+                CTYPE val; \
+                ECHECK(atot(field_value.constant.c_str(), *this, &val)); \
+                builder_.PushElement(val); \
+              } else { \
+                CTYPE val, valdef; \
+                ECHECK(atot(field_value.constant.c_str(), *this, &val)); \
+                ECHECK(atot(field->value.constant.c_str(), *this, &valdef)); \
+                builder_.AddElement(field_value.offset, val, valdef); \
+              } \
+              break;
+            FLATBUFFERS_GEN_TYPES_SCALAR(FLATBUFFERS_TD);
+          #undef FLATBUFFERS_TD
+          #define FLATBUFFERS_TD(ENUM, IDLTYPE, \
+            CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, RTYPE, KTYPE) \
+            case BASE_TYPE_ ## ENUM: \
+              builder_.Pad(field->padding); \
+              if (IsStruct(field->value.type)) { \
+                SerializeStruct(*field->value.type.struct_def, field_value); \
+              } else { \
+                CTYPE val; \
+                ECHECK(atot(field_value.constant.c_str(), *this, &val)); \
+                builder_.AddOffset(field_value.offset, val); \
+              } \
+              break;
+            FLATBUFFERS_GEN_TYPES_POINTER(FLATBUFFERS_TD);
+          #undef FLATBUFFERS_TD
+            case BASE_TYPE_ARRAY:
+              builder_.Pad(field->padding);
+              builder_.PushBytes(
+                reinterpret_cast<const uint8_t*>(field_value.constant.c_str()),
+                InlineSize(field_value.type));
+              break;
+              // clang-format on
+        }
+      }
+    }
+  }
+  for (size_t i = 0; i < fieldn_outer; i++) field_stack_.pop_back();
+
+  if (struct_def.fixed) {
+    builder_.ClearOffsets();
+    builder_.EndStruct();
+    FLATBUFFERS_ASSERT(value);
+    // Temporarily store this struct in the value string, since it is to
+    // be serialized in-place elsewhere.
+    value->assign(
+        reinterpret_cast<const char *>(builder_.GetCurrentBufferPointer()),
+        struct_def.bytesize);
+    builder_.PopBytes(struct_def.bytesize);
+    FLATBUFFERS_ASSERT(!ovalue);
+  } else {
+    auto val = builder_.EndTable(start);
+    if (ovalue) *ovalue = val;
+    if (value) *value = NumToString(val);
+  }
+  return NoError();
+}
+
+template <typename F>
+CheckedError Parser::ParseVectorDelimiters(uoffset_t &count, F body) {
+  EXPECT('[');
+  for (;;) {
+    if ((!opts.strict_json || !count) && Is(']')) break;
+    ECHECK(body(count));
+    count++;
+    if (Is(']')) break;
+    ECHECK(ParseComma());
+  }
+  NEXT();
+  return NoError();
+}
+
+CheckedError Parser::ParseVector(const Type &type, uoffset_t *ovalue,
+                                 FieldDef *field, size_t fieldn) {
+  uoffset_t count = 0;
+  auto err = ParseVectorDelimiters(count, [&](uoffset_t &) -> CheckedError {
+    Value val;
+    val.type = type;
+    ECHECK(Recurse([&]() {
+      return ParseAnyValue(val, field, fieldn, nullptr, count, true);
+    }));
+    field_stack_.push_back(std::make_pair(val, nullptr));
+    return NoError();
+  });
+  ECHECK(err);
+
+  builder_.StartVector(count * InlineSize(type) / InlineAlignment(type),
+                       InlineAlignment(type));
+  for (uoffset_t i = 0; i < count; i++) {
+    // start at the back, since we're building the data backwards.
+    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) \
+        case BASE_TYPE_ ## ENUM: \
+          if (IsStruct(val.type)) SerializeStruct(*val.type.struct_def, val); \
+          else { \
+             CTYPE elem; \
+             ECHECK(atot(val.constant.c_str(), *this, &elem)); \
+             builder_.PushElement(elem); \
+          } \
+          break;
+        FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
+      #undef FLATBUFFERS_TD
+      // clang-format on
+    }
+    field_stack_.pop_back();
+  }
+
+  builder_.ClearOffsets();
+  *ovalue = builder_.EndVector(count);
+  return NoError();
+}
+
+CheckedError Parser::ParseArray(Value &array) {
+  std::vector<Value> stack;
+  FlatBufferBuilder builder;
+  const auto &type = array.type.VectorType();
+  auto length = array.type.fixed_length;
+  uoffset_t count = 0;
+  auto err = ParseVectorDelimiters(count, [&](uoffset_t &) -> CheckedError {
+    vector_emplace_back(&stack, Value());
+    auto &val = stack.back();
+    val.type = type;
+    if (IsStruct(type)) {
+      ECHECK(ParseTable(*val.type.struct_def, &val.constant, nullptr));
+    } else {
+      ECHECK(ParseSingleValue(nullptr, val, false));
+    }
+    return NoError();
+  });
+  ECHECK(err);
+  if (length != count) return Error("Fixed-length array size is incorrect.");
+
+  for (auto it = stack.rbegin(); it != stack.rend(); ++it) {
+    auto &val = *it;
+    // clang-format off
+    switch (val.type.base_type) {
+      #define FLATBUFFERS_TD(ENUM, IDLTYPE, \
+        CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, RTYPE, KTYPE) \
+        case BASE_TYPE_ ## ENUM: \
+          if (IsStruct(val.type)) { \
+            SerializeStruct(builder, *val.type.struct_def, val); \
+          } else { \
+            CTYPE elem; \
+            ECHECK(atot(val.constant.c_str(), *this, &elem)); \
+            builder.PushElement(elem); \
+          } \
+        break;
+        FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
+      #undef FLATBUFFERS_TD
+      default: FLATBUFFERS_ASSERT(0);
+    }
+    // clang-format on
+  }
+
+  array.constant.assign(
+      reinterpret_cast<const char *>(builder.GetCurrentBufferPointer()),
+      InlineSize(array.type));
+  return NoError();
+}
+
+CheckedError Parser::ParseNestedFlatbuffer(Value &val, FieldDef *field,
+                                           size_t fieldn,
+                                           const StructDef *parent_struct_def) {
+  if (token_ == '[') {  // backwards compat for 'legacy' ubyte buffers
+    ECHECK(ParseAnyValue(val, field, fieldn, parent_struct_def, 0));
+  } else {
+    auto cursor_at_value_begin = cursor_;
+    ECHECK(SkipAnyJsonValue());
+    std::string substring(cursor_at_value_begin - 1, cursor_ - 1);
+
+    // Create and initialize new parser
+    Parser nested_parser;
+    FLATBUFFERS_ASSERT(field->nested_flatbuffer);
+    nested_parser.root_struct_def_ = field->nested_flatbuffer;
+    nested_parser.enums_ = enums_;
+    nested_parser.opts = opts;
+    nested_parser.uses_flexbuffers_ = uses_flexbuffers_;
+
+    // Parse JSON substring into new flatbuffer builder using nested_parser
+    bool ok = nested_parser.Parse(substring.c_str(), nullptr, nullptr);
+
+    // Clean nested_parser to avoid deleting the elements in
+    // the SymbolTables on destruction
+    nested_parser.enums_.dict.clear();
+    nested_parser.enums_.vec.clear();
+
+    if (!ok) {
+      ECHECK(Error(nested_parser.error_));
+    }
+    // Force alignment for nested flatbuffer
+    builder_.ForceVectorAlignment(nested_parser.builder_.GetSize(), sizeof(uint8_t),
+                                  nested_parser.builder_.GetBufferMinAlignment());
+
+    auto off = builder_.CreateVector(nested_parser.builder_.GetBufferPointer(),
+                                     nested_parser.builder_.GetSize());
+    val.constant = NumToString(off.o);
+  }
+  return NoError();
+}
+
+CheckedError Parser::ParseMetaData(SymbolTable<Value> *attributes) {
+  if (Is('(')) {
+    NEXT();
+    for (;;) {
+      auto name = attribute_;
+      if (false == (Is(kTokenIdentifier) || Is(kTokenStringConstant)))
+        return Error("attribute name must be either identifier or string: " +
+          name);
+      if (known_attributes_.find(name) == known_attributes_.end())
+        return Error("user define attributes must be declared before use: " +
+                     name);
+      NEXT();
+      auto e = new Value();
+      attributes->Add(name, e);
+      if (Is(':')) {
+        NEXT();
+        ECHECK(ParseSingleValue(&name, *e, true));
+      }
+      if (Is(')')) {
+        NEXT();
+        break;
+      }
+      EXPECT(',');
+    }
+  }
+  return NoError();
+}
+
+CheckedError Parser::TryTypedValue(const std::string *name, int dtoken,
+                                   bool check, Value &e, BaseType req,
+                                   bool *destmatch) {
+  bool match = dtoken == token_;
+  if (match) {
+    FLATBUFFERS_ASSERT(*destmatch == false);
+    *destmatch = true;
+    e.constant = attribute_;
+    // Check token match
+    if (!check) {
+      if (e.type.base_type == BASE_TYPE_NONE) {
+        e.type.base_type = req;
+      } else {
+        return Error(
+            std::string("type mismatch: expecting: ") +
+            kTypeNames[e.type.base_type] + ", found: " + kTypeNames[req] +
+            ", name: " + (name ? *name : "") + ", value: " + e.constant);
+      }
+    }
+    // The exponent suffix of hexadecimal float-point number is mandatory.
+    // A hex-integer constant is forbidden as an initializer of float number.
+    if ((kTokenFloatConstant != dtoken) && IsFloat(e.type.base_type)) {
+      const auto &s = e.constant;
+      const auto k = s.find_first_of("0123456789.");
+      if ((std::string::npos != k) && (s.length() > (k + 1)) &&
+          (s[k] == '0' && is_alpha_char(s[k + 1], 'X')) &&
+          (std::string::npos == s.find_first_of("pP", k + 2))) {
+        return Error(
+            "invalid number, the exponent suffix of hexadecimal "
+            "floating-point literals is mandatory: \"" +
+            s + "\"");
+      }
+    }
+
+    NEXT();
+  }
+  return NoError();
+}
+
+CheckedError Parser::ParseEnumFromString(const Type &type,
+                                         std::string *result) {
+  const auto base_type =
+      type.enum_def ? type.enum_def->underlying_type.base_type : type.base_type;
+  if (!IsInteger(base_type)) return Error("not a valid value for this field");
+  uint64_t u64 = 0;
+  for (size_t pos = 0; pos != std::string::npos;) {
+    const auto delim = attribute_.find_first_of(' ', pos);
+    const auto last = (std::string::npos == delim);
+    auto word = attribute_.substr(pos, !last ? delim - pos : std::string::npos);
+    pos = !last ? delim + 1 : std::string::npos;
+    const EnumVal *ev = nullptr;
+    if (type.enum_def) {
+      ev = type.enum_def->Lookup(word);
+    } else {
+      auto dot = word.find_first_of('.');
+      if (std::string::npos == dot)
+        return Error("enum values need to be qualified by an enum type");
+      auto enum_def_str = word.substr(0, dot);
+      const auto enum_def = LookupEnum(enum_def_str);
+      if (!enum_def) return Error("unknown enum: " + enum_def_str);
+      auto enum_val_str = word.substr(dot + 1);
+      ev = enum_def->Lookup(enum_val_str);
+    }
+    if (!ev) return Error("unknown enum value: " + word);
+    u64 |= ev->GetAsUInt64();
+  }
+  *result = IsUnsigned(base_type) ? NumToString(u64)
+                                  : NumToString(static_cast<int64_t>(u64));
+  return NoError();
+}
+
+CheckedError Parser::ParseHash(Value &e, FieldDef *field) {
+  FLATBUFFERS_ASSERT(field);
+  Value *hash_name = field->attributes.Lookup("hash");
+  switch (e.type.base_type) {
+    case BASE_TYPE_SHORT: {
+      auto hash = FindHashFunction16(hash_name->constant.c_str());
+      int16_t hashed_value = static_cast<int16_t>(hash(attribute_.c_str()));
+      e.constant = NumToString(hashed_value);
+      break;
+    }
+    case BASE_TYPE_USHORT: {
+      auto hash = FindHashFunction16(hash_name->constant.c_str());
+      uint16_t hashed_value = hash(attribute_.c_str());
+      e.constant = NumToString(hashed_value);
+      break;
+    }
+    case BASE_TYPE_INT: {
+      auto hash = FindHashFunction32(hash_name->constant.c_str());
+      int32_t hashed_value = static_cast<int32_t>(hash(attribute_.c_str()));
+      e.constant = NumToString(hashed_value);
+      break;
+    }
+    case BASE_TYPE_UINT: {
+      auto hash = FindHashFunction32(hash_name->constant.c_str());
+      uint32_t hashed_value = hash(attribute_.c_str());
+      e.constant = NumToString(hashed_value);
+      break;
+    }
+    case BASE_TYPE_LONG: {
+      auto hash = FindHashFunction64(hash_name->constant.c_str());
+      int64_t hashed_value = static_cast<int64_t>(hash(attribute_.c_str()));
+      e.constant = NumToString(hashed_value);
+      break;
+    }
+    case BASE_TYPE_ULONG: {
+      auto hash = FindHashFunction64(hash_name->constant.c_str());
+      uint64_t hashed_value = hash(attribute_.c_str());
+      e.constant = NumToString(hashed_value);
+      break;
+    }
+    default: FLATBUFFERS_ASSERT(0);
+  }
+  NEXT();
+  return NoError();
+}
+
+CheckedError Parser::TokenError() {
+  return Error("cannot parse value starting with: " + TokenToStringId(token_));
+}
+
+// Re-pack helper (ParseSingleValue) to normalize defaults of scalars.
+template<typename T> inline void SingleValueRepack(Value &e, T val) {
+  // Remove leading zeros.
+  if (IsInteger(e.type.base_type)) { e.constant = NumToString(val); }
+}
+#if defined(FLATBUFFERS_HAS_NEW_STRTOD) && (FLATBUFFERS_HAS_NEW_STRTOD > 0)
+// Normilaze defaults NaN to unsigned quiet-NaN(0).
+static inline void SingleValueRepack(Value& e, float val) {
+  if (val != val) e.constant = "nan";
+}
+static inline void SingleValueRepack(Value& e, double val) {
+  if (val != val) e.constant = "nan";
+}
+#endif
+
+CheckedError Parser::ParseSingleValue(const std::string *name, Value &e,
+                                      bool check_now) {
+  // First see if this could be a conversion function:
+  if (token_ == kTokenIdentifier && *cursor_ == '(') {
+    // todo: Extract processing of conversion functions to ParseFunction.
+    const auto functionname = attribute_;
+    if (!IsFloat(e.type.base_type)) {
+      return Error(functionname + ": type of argument mismatch, expecting: " +
+                   kTypeNames[BASE_TYPE_DOUBLE] +
+                   ", found: " + kTypeNames[e.type.base_type] +
+                   ", name: " + (name ? *name : "") + ", value: " + e.constant);
+    }
+    NEXT();
+    EXPECT('(');
+    ECHECK(Recurse([&]() { return ParseSingleValue(name, e, false); }));
+    EXPECT(')');
+    // calculate with double precision
+    double x, y = 0.0;
+    ECHECK(atot(e.constant.c_str(), *this, &x));
+    auto func_match = false;
+    // clang-format off
+    #define FLATBUFFERS_FN_DOUBLE(name, op) \
+      if (!func_match && functionname == name) { y = op; func_match = true; }
+    FLATBUFFERS_FN_DOUBLE("deg", x / kPi * 180);
+    FLATBUFFERS_FN_DOUBLE("rad", x * kPi / 180);
+    FLATBUFFERS_FN_DOUBLE("sin", sin(x));
+    FLATBUFFERS_FN_DOUBLE("cos", cos(x));
+    FLATBUFFERS_FN_DOUBLE("tan", tan(x));
+    FLATBUFFERS_FN_DOUBLE("asin", asin(x));
+    FLATBUFFERS_FN_DOUBLE("acos", acos(x));
+    FLATBUFFERS_FN_DOUBLE("atan", atan(x));
+    // TODO(wvo): add more useful conversion functions here.
+    #undef FLATBUFFERS_FN_DOUBLE
+    // clang-format on
+    if (true != func_match) {
+      return Error(std::string("Unknown conversion function: ") + functionname +
+                   ", field name: " + (name ? *name : "") +
+                   ", value: " + e.constant);
+    }
+    e.constant = NumToString(y);
+    return NoError();
+  }
+
+  auto match = false;
+  const auto in_type = e.type.base_type;
+  // clang-format off
+  #define IF_ECHECK_(force, dtoken, check, req)    \
+    if (!match && ((check) || IsConstTrue(force))) \
+    ECHECK(TryTypedValue(name, dtoken, check, e, req, &match))
+  #define TRY_ECHECK(dtoken, check, req) IF_ECHECK_(false, dtoken, check, req)
+  #define FORCE_ECHECK(dtoken, check, req) IF_ECHECK_(true, dtoken, check, req)
+  // clang-format on
+
+  if (token_ == kTokenStringConstant || token_ == kTokenIdentifier) {
+    const auto kTokenStringOrIdent = token_;
+    // The string type is a most probable type, check it first.
+    TRY_ECHECK(kTokenStringConstant, in_type == BASE_TYPE_STRING,
+               BASE_TYPE_STRING);
+
+    // avoid escaped and non-ascii in the string
+    if (!match && (token_ == kTokenStringConstant) && IsScalar(in_type) &&
+        !attr_is_trivial_ascii_string_) {
+      return Error(
+          std::string("type mismatch or invalid value, an initializer of "
+                      "non-string field must be trivial ASCII string: type: ") +
+          kTypeNames[in_type] + ", name: " + (name ? *name : "") +
+          ", value: " + attribute_);
+    }
+
+    // A boolean as true/false. Boolean as Integer check below.
+    if (!match && IsBool(in_type)) {
+      auto is_true = attribute_ == "true";
+      if (is_true || attribute_ == "false") {
+        attribute_ = is_true ? "1" : "0";
+        // accepts both kTokenStringConstant and kTokenIdentifier
+        TRY_ECHECK(kTokenStringOrIdent, IsBool(in_type), BASE_TYPE_BOOL);
+      }
+    }
+    // Check if this could be a string/identifier enum value.
+    // Enum can have only true integer base type.
+    if (!match && IsInteger(in_type) && !IsBool(in_type) &&
+        IsIdentifierStart(*attribute_.c_str())) {
+      ECHECK(ParseEnumFromString(e.type, &e.constant));
+      NEXT();
+      match = true;
+    }
+    // Parse a float/integer number from the string.
+    if (!match) check_now = true;  // Re-pack if parsed from string literal.
+    if (!match && (token_ == kTokenStringConstant) && IsScalar(in_type)) {
+      // remove trailing whitespaces from attribute_
+      auto last = attribute_.find_last_not_of(' ');
+      if (std::string::npos != last)  // has non-whitespace
+        attribute_.resize(last + 1);
+    }
+    // Float numbers or nan, inf, pi, etc.
+    TRY_ECHECK(kTokenStringOrIdent, IsFloat(in_type), BASE_TYPE_FLOAT);
+    // An integer constant in string.
+    TRY_ECHECK(kTokenStringOrIdent, IsInteger(in_type), BASE_TYPE_INT);
+    // Unknown tokens will be interpreted as string type.
+    // An attribute value may be a scalar or string constant.
+    FORCE_ECHECK(kTokenStringConstant, in_type == BASE_TYPE_STRING,
+                 BASE_TYPE_STRING);
+  } else {
+    // Try a float number.
+    TRY_ECHECK(kTokenFloatConstant, IsFloat(in_type), BASE_TYPE_FLOAT);
+    // Integer token can init any scalar (integer of float).
+    FORCE_ECHECK(kTokenIntegerConstant, IsScalar(in_type), BASE_TYPE_INT);
+  }
+#undef FORCE_ECHECK
+#undef TRY_ECHECK
+#undef IF_ECHECK_
+
+  if (!match) {
+    std::string msg;
+    msg += "Cannot assign token starting with '" + TokenToStringId(token_) +
+           "' to value of <" + std::string(kTypeNames[in_type]) + "> type.";
+    return Error(msg);
+  }
+  const auto match_type = e.type.base_type; // may differ from in_type
+  // The check_now flag must be true when parse a fbs-schema.
+  // This flag forces to check default scalar values or metadata of field.
+  // For JSON parser the flag should be false.
+  // If it is set for JSON each value will be checked twice (see ParseTable).
+  if (check_now && IsScalar(match_type)) {
+    // clang-format off
+    switch (match_type) {
+    #define FLATBUFFERS_TD(ENUM, IDLTYPE, \
+            CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, RTYPE, KTYPE) \
+            case BASE_TYPE_ ## ENUM: {\
+                CTYPE val; \
+                ECHECK(atot(e.constant.c_str(), *this, &val)); \
+                SingleValueRepack(e, val); \
+              break; }
+    FLATBUFFERS_GEN_TYPES_SCALAR(FLATBUFFERS_TD);
+    #undef FLATBUFFERS_TD
+    default: break;
+    }
+    // clang-format on
+  }
+  return NoError();
+}
+
+StructDef *Parser::LookupCreateStruct(const std::string &name,
+                                      bool create_if_new, bool definition) {
+  std::string qualified_name = current_namespace_->GetFullyQualifiedName(name);
+  // See if it exists pre-declared by an unqualified use.
+  auto struct_def = LookupStruct(name);
+  if (struct_def && struct_def->predecl) {
+    if (definition) {
+      // Make sure it has the current namespace, and is registered under its
+      // qualified name.
+      struct_def->defined_namespace = current_namespace_;
+      structs_.Move(name, qualified_name);
+    }
+    return struct_def;
+  }
+  // See if it exists pre-declared by an qualified use.
+  struct_def = LookupStruct(qualified_name);
+  if (struct_def && struct_def->predecl) {
+    if (definition) {
+      // Make sure it has the current namespace.
+      struct_def->defined_namespace = current_namespace_;
+    }
+    return struct_def;
+  }
+  if (!definition) {
+    // Search thru parent namespaces.
+    for (size_t components = current_namespace_->components.size();
+         components && !struct_def; components--) {
+      struct_def = LookupStruct(
+          current_namespace_->GetFullyQualifiedName(name, components - 1));
+    }
+  }
+  if (!struct_def && create_if_new) {
+    struct_def = new StructDef();
+    if (definition) {
+      structs_.Add(qualified_name, struct_def);
+      struct_def->name = name;
+      struct_def->defined_namespace = current_namespace_;
+    } else {
+      // Not a definition.
+      // Rather than failing, we create a "pre declared" StructDef, due to
+      // circular references, and check for errors at the end of parsing.
+      // It is defined in the current namespace, as the best guess what the
+      // final namespace will be.
+      structs_.Add(name, struct_def);
+      struct_def->name = name;
+      struct_def->defined_namespace = current_namespace_;
+      struct_def->original_location.reset(
+          new std::string(file_being_parsed_ + ":" + NumToString(line_)));
+    }
+  }
+  return struct_def;
+}
+
+const EnumVal *EnumDef::MinValue() const {
+  return vals.vec.empty() ? nullptr : vals.vec.front();
+}
+const EnumVal *EnumDef::MaxValue() const {
+  return vals.vec.empty() ? nullptr : vals.vec.back();
+}
+
+template<typename T> static uint64_t EnumDistanceImpl(T e1, T e2) {
+  if (e1 < e2) { std::swap(e1, e2); }  // use std for scalars
+  // Signed overflow may occur, use unsigned calculation.
+  // The unsigned overflow is well-defined by C++ standard (modulo 2^n).
+  return static_cast<uint64_t>(e1) - static_cast<uint64_t>(e2);
+}
+
+uint64_t EnumDef::Distance(const EnumVal *v1, const EnumVal *v2) const {
+  return IsUInt64() ? EnumDistanceImpl(v1->GetAsUInt64(), v2->GetAsUInt64())
+                    : EnumDistanceImpl(v1->GetAsInt64(), v2->GetAsInt64());
+}
+
+std::string EnumDef::AllFlags() const {
+  FLATBUFFERS_ASSERT(attributes.Lookup("bit_flags"));
+  uint64_t u64 = 0;
+  for (auto it = Vals().begin(); it != Vals().end(); ++it) {
+    u64 |= (*it)->GetAsUInt64();
+  }
+  return IsUInt64() ? NumToString(u64) : NumToString(static_cast<int64_t>(u64));
+}
+
+EnumVal *EnumDef::ReverseLookup(int64_t enum_idx,
+                                bool skip_union_default) const {
+  auto skip_first = static_cast<int>(is_union && skip_union_default);
+  for (auto it = Vals().begin() + skip_first; it != Vals().end(); ++it) {
+    if ((*it)->GetAsInt64() == enum_idx) { return *it; }
+  }
+  return nullptr;
+}
+
+EnumVal *EnumDef::FindByValue(const std::string &constant) const {
+  int64_t i64;
+  auto done = false;
+  if (IsUInt64()) {
+    uint64_t u64;  // avoid reinterpret_cast of pointers
+    done = StringToNumber(constant.c_str(), &u64);
+    i64 = static_cast<int64_t>(u64);
+  } else {
+    done = StringToNumber(constant.c_str(), &i64);
+  }
+  FLATBUFFERS_ASSERT(done);
+  if (!done) return nullptr;
+  return ReverseLookup(i64, false);
+}
+
+void EnumDef::SortByValue() {
+  auto &v = vals.vec;
+  if (IsUInt64())
+    std::sort(v.begin(), v.end(), [](const EnumVal *e1, const EnumVal *e2) {
+      return e1->GetAsUInt64() < e2->GetAsUInt64();
+    });
+  else
+    std::sort(v.begin(), v.end(), [](const EnumVal *e1, const EnumVal *e2) {
+      return e1->GetAsInt64() < e2->GetAsInt64();
+    });
+}
+
+void EnumDef::RemoveDuplicates() {
+  // This method depends form SymbolTable implementation!
+  // 1) vals.vec - owner (raw pointer)
+  // 2) vals.dict - access map
+  auto first = vals.vec.begin();
+  auto last = vals.vec.end();
+  if (first == last) return;
+  auto result = first;
+  while (++first != last) {
+    if ((*result)->value != (*first)->value) {
+      *(++result) = *first;
+    } else {
+      auto ev = *first;
+      for (auto it = vals.dict.begin(); it != vals.dict.end(); ++it) {
+        if (it->second == ev) it->second = *result;  // reassign
+      }
+      delete ev;  // delete enum value
+      *first = nullptr;
+    }
+  }
+  vals.vec.erase(++result, last);
+}
+
+template<typename T> void EnumDef::ChangeEnumValue(EnumVal *ev, T new_value) {
+  ev->value = static_cast<int64_t>(new_value);
+}
+
+namespace EnumHelper {
+template<BaseType E> struct EnumValType { typedef int64_t type; };
+template<> struct EnumValType<BASE_TYPE_ULONG> { typedef uint64_t type; };
+}  // namespace EnumHelper
+
+struct EnumValBuilder {
+  EnumVal *CreateEnumerator(const std::string &ev_name) {
+    FLATBUFFERS_ASSERT(!temp);
+    auto first = enum_def.vals.vec.empty();
+    user_value = first;
+    temp = new EnumVal(ev_name, first ? 0 : enum_def.vals.vec.back()->value);
+    return temp;
+  }
+
+  EnumVal *CreateEnumerator(const std::string &ev_name, int64_t val) {
+    FLATBUFFERS_ASSERT(!temp);
+    user_value = true;
+    temp = new EnumVal(ev_name, val);
+    return temp;
+  }
+
+  FLATBUFFERS_CHECKED_ERROR AcceptEnumerator(const std::string &name) {
+    FLATBUFFERS_ASSERT(temp);
+    ECHECK(ValidateValue(&temp->value, false == user_value));
+    FLATBUFFERS_ASSERT((temp->union_type.enum_def == nullptr) ||
+                       (temp->union_type.enum_def == &enum_def));
+    auto not_unique = enum_def.vals.Add(name, temp);
+    temp = nullptr;
+    if (not_unique) return parser.Error("enum value already exists: " + name);
+    return NoError();
+  }
+
+  FLATBUFFERS_CHECKED_ERROR AcceptEnumerator() {
+    return AcceptEnumerator(temp->name);
+  }
+
+  FLATBUFFERS_CHECKED_ERROR AssignEnumeratorValue(const std::string &value) {
+    user_value = true;
+    auto fit = false;
+    auto ascending = false;
+    if (enum_def.IsUInt64()) {
+      uint64_t u64;
+      fit = StringToNumber(value.c_str(), &u64);
+      ascending = u64 > temp->GetAsUInt64();
+      temp->value = static_cast<int64_t>(u64);  // well-defined since C++20.
+    } else {
+      int64_t i64;
+      fit = StringToNumber(value.c_str(), &i64);
+      ascending = i64 > temp->GetAsInt64();
+      temp->value = i64;
+    }
+    if (!fit) return parser.Error("enum value does not fit, \"" + value + "\"");
+    if (!ascending && strict_ascending && !enum_def.vals.vec.empty())
+      return parser.Error("enum values must be specified in ascending order");
+    return NoError();
+  }
+
+  template<BaseType E, typename CTYPE>
+  inline FLATBUFFERS_CHECKED_ERROR ValidateImpl(int64_t *ev, int m) {
+    typedef typename EnumHelper::EnumValType<E>::type T;  // int64_t or uint64_t
+    static_assert(sizeof(T) == sizeof(int64_t), "invalid EnumValType");
+    const auto v = static_cast<T>(*ev);
+    auto up = static_cast<T>((flatbuffers::numeric_limits<CTYPE>::max)());
+    auto dn = static_cast<T>((flatbuffers::numeric_limits<CTYPE>::lowest)());
+    if (v < dn || v > (up - m)) {
+      return parser.Error("enum value does not fit, \"" + NumToString(v) +
+                          (m ? " + 1\"" : "\"") + " out of " +
+                          TypeToIntervalString<CTYPE>());
+    }
+    *ev = static_cast<int64_t>(v + m);  // well-defined since C++20.
+    return NoError();
+  }
+
+  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)                         \
+      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);
+    #undef FLATBUFFERS_TD
+    default: break;
+    }
+    // clang-format on
+    return parser.Error("fatal: invalid enum underlying type");
+  }
+
+  EnumValBuilder(Parser &_parser, EnumDef &_enum_def, bool strict_order = true)
+      : parser(_parser),
+        enum_def(_enum_def),
+        temp(nullptr),
+        strict_ascending(strict_order),
+        user_value(false) {}
+
+  ~EnumValBuilder() { delete temp; }
+
+  Parser &parser;
+  EnumDef &enum_def;
+  EnumVal *temp;
+  const bool strict_ascending;
+  bool user_value;
+};
+
+CheckedError Parser::ParseEnum(const bool is_union, EnumDef **dest) {
+  std::vector<std::string> enum_comment = doc_comment_;
+  NEXT();
+  std::string enum_name = attribute_;
+  EXPECT(kTokenIdentifier);
+  EnumDef *enum_def;
+  ECHECK(StartEnum(enum_name, is_union, &enum_def));
+  enum_def->doc_comment = enum_comment;
+  if (!is_union && !opts.proto_mode) {
+    // Give specialized error message, since this type spec used to
+    // be optional in the first FlatBuffers release.
+    if (!Is(':')) {
+      return Error(
+          "must specify the underlying integer type for this"
+          " enum (e.g. \': short\', which was the default).");
+    } else {
+      NEXT();
+    }
+    // Specify the integer type underlying this enum.
+    ECHECK(ParseType(enum_def->underlying_type));
+    if (!IsInteger(enum_def->underlying_type.base_type) ||
+        IsBool(enum_def->underlying_type.base_type))
+      return Error("underlying enum type must be integral");
+    // Make this type refer back to the enum it was derived from.
+    enum_def->underlying_type.enum_def = enum_def;
+  }
+  ECHECK(ParseMetaData(&enum_def->attributes));
+  const auto underlying_type = enum_def->underlying_type.base_type;
+  if (enum_def->attributes.Lookup("bit_flags") &&
+      !IsUnsigned(underlying_type)) {
+    // todo: Convert to the Error in the future?
+    Warning("underlying type of bit_flags enum must be unsigned");
+  }
+  // Protobuf allows them to be specified in any order, so sort afterwards.
+  const auto strict_ascending = (false == opts.proto_mode);
+  EnumValBuilder evb(*this, *enum_def, strict_ascending);
+  EXPECT('{');
+  // A lot of code generatos expect that an enum is not-empty.
+  if ((is_union || Is('}')) && !opts.proto_mode) {
+    evb.CreateEnumerator("NONE");
+    ECHECK(evb.AcceptEnumerator());
+  }
+  std::set<std::pair<BaseType, StructDef *>> union_types;
+  while (!Is('}')) {
+    if (opts.proto_mode && attribute_ == "option") {
+      ECHECK(ParseProtoOption());
+    } else {
+      auto &ev = *evb.CreateEnumerator(attribute_);
+      auto full_name = ev.name;
+      ev.doc_comment = doc_comment_;
+      EXPECT(kTokenIdentifier);
+      if (is_union) {
+        ECHECK(ParseNamespacing(&full_name, &ev.name));
+        if (opts.union_value_namespacing) {
+          // Since we can't namespace the actual enum identifiers, turn
+          // namespace parts into part of the identifier.
+          ev.name = full_name;
+          std::replace(ev.name.begin(), ev.name.end(), '.', '_');
+        }
+        if (Is(':')) {
+          NEXT();
+          ECHECK(ParseType(ev.union_type));
+          if (ev.union_type.base_type != BASE_TYPE_STRUCT &&
+              ev.union_type.base_type != BASE_TYPE_STRING)
+            return Error("union value type may only be table/struct/string");
+        } else {
+          ev.union_type = Type(BASE_TYPE_STRUCT, LookupCreateStruct(full_name));
+        }
+        if (!enum_def->uses_multiple_type_instances) {
+          auto ins = union_types.insert(std::make_pair(
+              ev.union_type.base_type, ev.union_type.struct_def));
+          enum_def->uses_multiple_type_instances = (false == ins.second);
+        }
+      }
+
+      if (Is('=')) {
+        NEXT();
+        ECHECK(evb.AssignEnumeratorValue(attribute_));
+        EXPECT(kTokenIntegerConstant);
+      } else if (false == strict_ascending) {
+        // The opts.proto_mode flag is active.
+        return Error("Protobuf mode doesn't allow implicit enum values.");
+      }
+
+      ECHECK(evb.AcceptEnumerator());
+
+      if (opts.proto_mode && Is('[')) {
+        NEXT();
+        // ignore attributes on enums.
+        while (token_ != ']') NEXT();
+        NEXT();
+      }
+    }
+    if (!Is(opts.proto_mode ? ';' : ',')) break;
+    NEXT();
+  }
+  EXPECT('}');
+
+  // At this point, the enum can be empty if input is invalid proto-file.
+  if (!enum_def->size())
+    return Error("incomplete enum declaration, values not found");
+
+  if (enum_def->attributes.Lookup("bit_flags")) {
+    const auto base_width = static_cast<uint64_t>(8 * SizeOf(underlying_type));
+    for (auto it = enum_def->Vals().begin(); it != enum_def->Vals().end();
+         ++it) {
+      auto ev = *it;
+      const auto u = ev->GetAsUInt64();
+      // Stop manipulations with the sign.
+      if (!IsUnsigned(underlying_type) && u == (base_width - 1))
+        return Error("underlying type of bit_flags enum must be unsigned");
+      if (u >= base_width)
+        return Error("bit flag out of range of underlying integral type");
+      enum_def->ChangeEnumValue(ev, 1ULL << u);
+    }
+  }
+
+  if (false == strict_ascending)
+    enum_def->SortByValue();  // Must be sorted to use MinValue/MaxValue.
+
+  if (dest) *dest = enum_def;
+  types_.Add(current_namespace_->GetFullyQualifiedName(enum_def->name),
+             new Type(BASE_TYPE_UNION, nullptr, enum_def));
+  return NoError();
+}
+
+CheckedError Parser::StartStruct(const std::string &name, StructDef **dest) {
+  auto &struct_def = *LookupCreateStruct(name, true, true);
+  if (!struct_def.predecl) return Error("datatype already exists: " + name);
+  struct_def.predecl = false;
+  struct_def.name = name;
+  struct_def.file = file_being_parsed_;
+  // Move this struct to the back of the vector just in case it was predeclared,
+  // to preserve declaration order.
+  *std::remove(structs_.vec.begin(), structs_.vec.end(), &struct_def) =
+      &struct_def;
+  *dest = &struct_def;
+  return NoError();
+}
+
+CheckedError Parser::CheckClash(std::vector<FieldDef *> &fields,
+                                StructDef *struct_def, const char *suffix,
+                                BaseType basetype) {
+  auto len = strlen(suffix);
+  for (auto it = fields.begin(); it != fields.end(); ++it) {
+    auto &fname = (*it)->name;
+    if (fname.length() > len &&
+        fname.compare(fname.length() - len, len, suffix) == 0 &&
+        (*it)->value.type.base_type != BASE_TYPE_UTYPE) {
+      auto field =
+          struct_def->fields.Lookup(fname.substr(0, fname.length() - len));
+      if (field && field->value.type.base_type == basetype)
+        return Error("Field " + fname +
+                     " would clash with generated functions for field " +
+                     field->name);
+    }
+  }
+  return NoError();
+}
+
+bool Parser::SupportsAdvancedUnionFeatures() const {
+  return opts.lang_to_generate != 0 &&
+         (opts.lang_to_generate & ~(IDLOptions::kCpp | IDLOptions::kJs |
+                                    IDLOptions::kTs | IDLOptions::kPhp |
+                                    IDLOptions::kJava | IDLOptions::kCSharp |
+                                    IDLOptions::kKotlin |
+                                    IDLOptions::kBinary)) == 0;
+}
+
+bool Parser::SupportsAdvancedArrayFeatures() const {
+  return (opts.lang_to_generate &
+          ~(IDLOptions::kCpp | IDLOptions::kPython | IDLOptions::kJava |
+            IDLOptions::kCSharp | IDLOptions::kJsonSchema | IDLOptions::kJson |
+            IDLOptions::kBinary)) == 0;
+}
+
+Namespace *Parser::UniqueNamespace(Namespace *ns) {
+  for (auto it = namespaces_.begin(); it != namespaces_.end(); ++it) {
+    if (ns->components == (*it)->components) {
+      delete ns;
+      return *it;
+    }
+  }
+  namespaces_.push_back(ns);
+  return ns;
+}
+
+std::string Parser::UnqualifiedName(const std::string &full_qualified_name) {
+  Namespace *ns = new Namespace();
+
+  std::size_t current, previous = 0;
+  current = full_qualified_name.find('.');
+  while (current != std::string::npos) {
+    ns->components.push_back(
+        full_qualified_name.substr(previous, current - previous));
+    previous = current + 1;
+    current = full_qualified_name.find('.', previous);
+  }
+  current_namespace_ = UniqueNamespace(ns);
+  return full_qualified_name.substr(previous, current - previous);
+}
+
+static bool compareFieldDefs(const FieldDef *a, const FieldDef *b) {
+  auto a_id = atoi(a->attributes.Lookup("id")->constant.c_str());
+  auto b_id = atoi(b->attributes.Lookup("id")->constant.c_str());
+  return a_id < b_id;
+}
+
+CheckedError Parser::ParseDecl() {
+  std::vector<std::string> dc = doc_comment_;
+  bool fixed = IsIdent("struct");
+  if (!fixed && !IsIdent("table")) return Error("declaration expected");
+  NEXT();
+  std::string name = attribute_;
+  EXPECT(kTokenIdentifier);
+  StructDef *struct_def;
+  ECHECK(StartStruct(name, &struct_def));
+  struct_def->doc_comment = dc;
+  struct_def->fixed = fixed;
+  ECHECK(ParseMetaData(&struct_def->attributes));
+  struct_def->sortbysize =
+      struct_def->attributes.Lookup("original_order") == nullptr && !fixed;
+  EXPECT('{');
+  while (token_ != '}') ECHECK(ParseField(*struct_def));
+  auto force_align = struct_def->attributes.Lookup("force_align");
+  if (fixed) {
+    if (force_align) {
+      auto align = static_cast<size_t>(atoi(force_align->constant.c_str()));
+      if (force_align->type.base_type != BASE_TYPE_INT ||
+          align < struct_def->minalign || align > FLATBUFFERS_MAX_ALIGNMENT ||
+          align & (align - 1))
+        return Error(
+            "force_align must be a power of two integer ranging from the"
+            "struct\'s natural alignment to " +
+            NumToString(FLATBUFFERS_MAX_ALIGNMENT));
+      struct_def->minalign = align;
+    }
+    if (!struct_def->bytesize) return Error("size 0 structs not allowed");
+  }
+  struct_def->PadLastField(struct_def->minalign);
+  // Check if this is a table that has manual id assignments
+  auto &fields = struct_def->fields.vec;
+  if (!fixed && fields.size()) {
+    size_t num_id_fields = 0;
+    for (auto it = fields.begin(); it != fields.end(); ++it) {
+      if ((*it)->attributes.Lookup("id")) num_id_fields++;
+    }
+    // If any fields have ids..
+    if (num_id_fields) {
+      // Then all fields must have them.
+      if (num_id_fields != fields.size())
+        return Error(
+            "either all fields or no fields must have an 'id' attribute");
+      // Simply sort by id, then the fields are the same as if no ids had
+      // been specified.
+      std::sort(fields.begin(), fields.end(), compareFieldDefs);
+      // Verify we have a contiguous set, and reassign vtable offsets.
+      for (int i = 0; i < static_cast<int>(fields.size()); i++) {
+        if (i != atoi(fields[i]->attributes.Lookup("id")->constant.c_str()))
+          return Error("field id\'s must be consecutive from 0, id " +
+                       NumToString(i) + " missing or set twice");
+        fields[i]->value.offset = FieldIndexToOffset(static_cast<voffset_t>(i));
+      }
+    }
+  }
+
+  ECHECK(
+      CheckClash(fields, struct_def, UnionTypeFieldSuffix(), BASE_TYPE_UNION));
+  ECHECK(CheckClash(fields, struct_def, "Type", BASE_TYPE_UNION));
+  ECHECK(CheckClash(fields, struct_def, "_length", BASE_TYPE_VECTOR));
+  ECHECK(CheckClash(fields, struct_def, "Length", BASE_TYPE_VECTOR));
+  ECHECK(CheckClash(fields, struct_def, "_byte_vector", BASE_TYPE_STRING));
+  ECHECK(CheckClash(fields, struct_def, "ByteVector", BASE_TYPE_STRING));
+  EXPECT('}');
+  types_.Add(current_namespace_->GetFullyQualifiedName(struct_def->name),
+             new Type(BASE_TYPE_STRUCT, struct_def, nullptr));
+  return NoError();
+}
+
+CheckedError Parser::ParseService() {
+  std::vector<std::string> service_comment = doc_comment_;
+  NEXT();
+  auto service_name = attribute_;
+  EXPECT(kTokenIdentifier);
+  auto &service_def = *new ServiceDef();
+  service_def.name = service_name;
+  service_def.file = file_being_parsed_;
+  service_def.doc_comment = service_comment;
+  service_def.defined_namespace = current_namespace_;
+  if (services_.Add(current_namespace_->GetFullyQualifiedName(service_name),
+                    &service_def))
+    return Error("service already exists: " + service_name);
+  ECHECK(ParseMetaData(&service_def.attributes));
+  EXPECT('{');
+  do {
+    std::vector<std::string> doc_comment = doc_comment_;
+    auto rpc_name = attribute_;
+    EXPECT(kTokenIdentifier);
+    EXPECT('(');
+    Type reqtype, resptype;
+    ECHECK(ParseTypeIdent(reqtype));
+    EXPECT(')');
+    EXPECT(':');
+    ECHECK(ParseTypeIdent(resptype));
+    if (reqtype.base_type != BASE_TYPE_STRUCT || reqtype.struct_def->fixed ||
+        resptype.base_type != BASE_TYPE_STRUCT || resptype.struct_def->fixed)
+      return Error("rpc request and response types must be tables");
+    auto &rpc = *new RPCCall();
+    rpc.name = rpc_name;
+    rpc.request = reqtype.struct_def;
+    rpc.response = resptype.struct_def;
+    rpc.doc_comment = doc_comment;
+    if (service_def.calls.Add(rpc_name, &rpc))
+      return Error("rpc already exists: " + rpc_name);
+    ECHECK(ParseMetaData(&rpc.attributes));
+    EXPECT(';');
+  } while (token_ != '}');
+  NEXT();
+  return NoError();
+}
+
+bool Parser::SetRootType(const char *name) {
+  root_struct_def_ = LookupStruct(name);
+  if (!root_struct_def_)
+    root_struct_def_ =
+        LookupStruct(current_namespace_->GetFullyQualifiedName(name));
+  return root_struct_def_ != nullptr;
+}
+
+void Parser::MarkGenerated() {
+  // This function marks all existing definitions as having already
+  // been generated, which signals no code for included files should be
+  // generated.
+  for (auto it = enums_.vec.begin(); it != enums_.vec.end(); ++it) {
+    (*it)->generated = true;
+  }
+  for (auto it = structs_.vec.begin(); it != structs_.vec.end(); ++it) {
+    if (!(*it)->predecl) { (*it)->generated = true; }
+  }
+  for (auto it = services_.vec.begin(); it != services_.vec.end(); ++it) {
+    (*it)->generated = true;
+  }
+}
+
+CheckedError Parser::ParseNamespace() {
+  NEXT();
+  auto ns = new Namespace();
+  namespaces_.push_back(ns);  // Store it here to not leak upon error.
+  if (token_ != ';') {
+    for (;;) {
+      ns->components.push_back(attribute_);
+      EXPECT(kTokenIdentifier);
+      if (Is('.')) NEXT() else break;
+    }
+  }
+  namespaces_.pop_back();
+  current_namespace_ = UniqueNamespace(ns);
+  EXPECT(';');
+  return NoError();
+}
+
+// Best effort parsing of .proto declarations, with the aim to turn them
+// in the closest corresponding FlatBuffer equivalent.
+// We parse everything as identifiers instead of keywords, since we don't
+// want protobuf keywords to become invalid identifiers in FlatBuffers.
+CheckedError Parser::ParseProtoDecl() {
+  bool isextend = IsIdent("extend");
+  if (IsIdent("package")) {
+    // These are identical in syntax to FlatBuffer's namespace decl.
+    ECHECK(ParseNamespace());
+  } else if (IsIdent("message") || isextend) {
+    std::vector<std::string> struct_comment = doc_comment_;
+    NEXT();
+    StructDef *struct_def = nullptr;
+    Namespace *parent_namespace = nullptr;
+    if (isextend) {
+      if (Is('.')) NEXT();  // qualified names may start with a . ?
+      auto id = attribute_;
+      EXPECT(kTokenIdentifier);
+      ECHECK(ParseNamespacing(&id, nullptr));
+      struct_def = LookupCreateStruct(id, false);
+      if (!struct_def)
+        return Error("cannot extend unknown message type: " + id);
+    } else {
+      std::string name = attribute_;
+      EXPECT(kTokenIdentifier);
+      ECHECK(StartStruct(name, &struct_def));
+      // Since message definitions can be nested, we create a new namespace.
+      auto ns = new Namespace();
+      // Copy of current namespace.
+      *ns = *current_namespace_;
+      // But with current message name.
+      ns->components.push_back(name);
+      ns->from_table++;
+      parent_namespace = current_namespace_;
+      current_namespace_ = UniqueNamespace(ns);
+    }
+    struct_def->doc_comment = struct_comment;
+    ECHECK(ParseProtoFields(struct_def, isextend, false));
+    if (!isextend) { current_namespace_ = parent_namespace; }
+    if (Is(';')) NEXT();
+  } else if (IsIdent("enum")) {
+    // These are almost the same, just with different terminator:
+    EnumDef *enum_def;
+    ECHECK(ParseEnum(false, &enum_def));
+    if (Is(';')) NEXT();
+    // Temp: remove any duplicates, as .fbs files can't handle them.
+    enum_def->RemoveDuplicates();
+  } else if (IsIdent("syntax")) {  // Skip these.
+    NEXT();
+    EXPECT('=');
+    EXPECT(kTokenStringConstant);
+    EXPECT(';');
+  } else if (IsIdent("option")) {  // Skip these.
+    ECHECK(ParseProtoOption());
+    EXPECT(';');
+  } else if (IsIdent("service")) {  // Skip these.
+    NEXT();
+    EXPECT(kTokenIdentifier);
+    ECHECK(ParseProtoCurliesOrIdent());
+  } else {
+    return Error("don\'t know how to parse .proto declaration starting with " +
+                 TokenToStringId(token_));
+  }
+  return NoError();
+}
+
+CheckedError Parser::StartEnum(const std::string &enum_name, bool is_union,
+                               EnumDef **dest) {
+  auto &enum_def = *new EnumDef();
+  enum_def.name = enum_name;
+  enum_def.file = file_being_parsed_;
+  enum_def.doc_comment = doc_comment_;
+  enum_def.is_union = is_union;
+  enum_def.defined_namespace = current_namespace_;
+  if (enums_.Add(current_namespace_->GetFullyQualifiedName(enum_name),
+                 &enum_def))
+    return Error("enum already exists: " + enum_name);
+  enum_def.underlying_type.base_type = is_union ? BASE_TYPE_UTYPE
+                                                : BASE_TYPE_INT;
+  enum_def.underlying_type.enum_def = &enum_def;
+  if (dest) *dest = &enum_def;
+  return NoError();
+}
+
+CheckedError Parser::ParseProtoFields(StructDef *struct_def, bool isextend,
+                                      bool inside_oneof) {
+  EXPECT('{');
+  while (token_ != '}') {
+    if (IsIdent("message") || IsIdent("extend") || IsIdent("enum")) {
+      // Nested declarations.
+      ECHECK(ParseProtoDecl());
+    } else if (IsIdent("extensions")) {  // Skip these.
+      NEXT();
+      EXPECT(kTokenIntegerConstant);
+      if (Is(kTokenIdentifier)) {
+        NEXT();  // to
+        NEXT();  // num
+      }
+      EXPECT(';');
+    } else if (IsIdent("option")) {  // Skip these.
+      ECHECK(ParseProtoOption());
+      EXPECT(';');
+    } else if (IsIdent("reserved")) {  // Skip these.
+      NEXT();
+      while (!Is(';')) { NEXT(); }  // A variety of formats, just skip.
+      NEXT();
+    } else {
+      std::vector<std::string> field_comment = doc_comment_;
+      // Parse the qualifier.
+      bool required = false;
+      bool repeated = false;
+      bool oneof = false;
+      if (!inside_oneof) {
+        if (IsIdent("optional")) {
+          // This is the default.
+          NEXT();
+        } else if (IsIdent("required")) {
+          required = true;
+          NEXT();
+        } else if (IsIdent("repeated")) {
+          repeated = true;
+          NEXT();
+        } else if (IsIdent("oneof")) {
+          oneof = true;
+          NEXT();
+        } else {
+          // can't error, proto3 allows decls without any of the above.
+        }
+      }
+      StructDef *anonymous_struct = nullptr;
+      EnumDef *oneof_union = nullptr;
+      Type type;
+      if (IsIdent("group") || oneof) {
+        if (!oneof) NEXT();
+        if (oneof && opts.proto_oneof_union) {
+          auto name = MakeCamel(attribute_, true) + "Union";
+          ECHECK(StartEnum(name, true, &oneof_union));
+          type = Type(BASE_TYPE_UNION, nullptr, oneof_union);
+        } else {
+          auto name = "Anonymous" + NumToString(anonymous_counter++);
+          ECHECK(StartStruct(name, &anonymous_struct));
+          type = Type(BASE_TYPE_STRUCT, anonymous_struct);
+        }
+      } else {
+        ECHECK(ParseTypeFromProtoType(&type));
+      }
+      // Repeated elements get mapped to a vector.
+      if (repeated) {
+        type.element = type.base_type;
+        type.base_type = BASE_TYPE_VECTOR;
+        if (type.element == BASE_TYPE_VECTOR) {
+          // We have a vector or vectors, which FlatBuffers doesn't support.
+          // For now make it a vector of string (since the source is likely
+          // "repeated bytes").
+          // TODO(wvo): A better solution would be to wrap this in a table.
+          type.element = BASE_TYPE_STRING;
+        }
+      }
+      std::string name = attribute_;
+      EXPECT(kTokenIdentifier);
+      if (!oneof) {
+        // Parse the field id. Since we're just translating schemas, not
+        // any kind of binary compatibility, we can safely ignore these, and
+        // assign our own.
+        EXPECT('=');
+        EXPECT(kTokenIntegerConstant);
+      }
+      FieldDef *field = nullptr;
+      if (isextend) {
+        // We allow a field to be re-defined when extending.
+        // TODO: are there situations where that is problematic?
+        field = struct_def->fields.Lookup(name);
+      }
+      if (!field) ECHECK(AddField(*struct_def, name, type, &field));
+      field->doc_comment = field_comment;
+      if (!IsScalar(type.base_type)) field->required = required;
+      // See if there's a default specified.
+      if (Is('[')) {
+        NEXT();
+        for (;;) {
+          auto key = attribute_;
+          ECHECK(ParseProtoKey());
+          EXPECT('=');
+          auto val = attribute_;
+          ECHECK(ParseProtoCurliesOrIdent());
+          if (key == "default") {
+            // Temp: skip non-numeric defaults (enums).
+            auto numeric = strpbrk(val.c_str(), "0123456789-+.");
+            if (IsScalar(type.base_type) && numeric == val.c_str())
+              field->value.constant = val;
+          } else if (key == "deprecated") {
+            field->deprecated = val == "true";
+          }
+          if (!Is(',')) break;
+          NEXT();
+        }
+        EXPECT(']');
+      }
+      if (anonymous_struct) {
+        ECHECK(ParseProtoFields(anonymous_struct, false, oneof));
+        if (Is(';')) NEXT();
+      } else if (oneof_union) {
+        // Parse into a temporary StructDef, then transfer fields into an
+        // EnumDef describing the oneof as a union.
+        StructDef oneof_struct;
+        ECHECK(ParseProtoFields(&oneof_struct, false, oneof));
+        if (Is(';')) NEXT();
+        for (auto field_it = oneof_struct.fields.vec.begin();
+             field_it != oneof_struct.fields.vec.end(); ++field_it) {
+          const auto &oneof_field = **field_it;
+          const auto &oneof_type = oneof_field.value.type;
+          if (oneof_type.base_type != BASE_TYPE_STRUCT ||
+              !oneof_type.struct_def || oneof_type.struct_def->fixed)
+            return Error("oneof '" + name +
+                "' cannot be mapped to a union because member '" +
+                oneof_field.name + "' is not a table type.");
+          EnumValBuilder evb(*this, *oneof_union);
+          auto ev = evb.CreateEnumerator(oneof_type.struct_def->name);
+          ev->union_type = oneof_type;
+          ev->doc_comment = oneof_field.doc_comment;
+          ECHECK(evb.AcceptEnumerator(oneof_field.name));
+        }
+      } else {
+        EXPECT(';');
+      }
+    }
+  }
+  NEXT();
+  return NoError();
+}
+
+CheckedError Parser::ParseProtoKey() {
+  if (token_ == '(') {
+    NEXT();
+    // Skip "(a.b)" style custom attributes.
+    while (token_ == '.' || token_ == kTokenIdentifier) NEXT();
+    EXPECT(')');
+    while (Is('.')) {
+      NEXT();
+      EXPECT(kTokenIdentifier);
+    }
+  } else {
+    EXPECT(kTokenIdentifier);
+  }
+  return NoError();
+}
+
+CheckedError Parser::ParseProtoCurliesOrIdent() {
+  if (Is('{')) {
+    NEXT();
+    for (int nesting = 1; nesting;) {
+      if (token_ == '{')
+        nesting++;
+      else if (token_ == '}')
+        nesting--;
+      NEXT();
+    }
+  } else {
+    NEXT();  // Any single token.
+  }
+  return NoError();
+}
+
+CheckedError Parser::ParseProtoOption() {
+  NEXT();
+  ECHECK(ParseProtoKey());
+  EXPECT('=');
+  ECHECK(ParseProtoCurliesOrIdent());
+  return NoError();
+}
+
+// Parse a protobuf type, and map it to the corresponding FlatBuffer one.
+CheckedError Parser::ParseTypeFromProtoType(Type *type) {
+  struct type_lookup {
+    const char *proto_type;
+    BaseType fb_type, element;
+  };
+  static type_lookup lookup[] = {
+    { "float", BASE_TYPE_FLOAT, BASE_TYPE_NONE },
+    { "double", BASE_TYPE_DOUBLE, BASE_TYPE_NONE },
+    { "int32", BASE_TYPE_INT, BASE_TYPE_NONE },
+    { "int64", BASE_TYPE_LONG, BASE_TYPE_NONE },
+    { "uint32", BASE_TYPE_UINT, BASE_TYPE_NONE },
+    { "uint64", BASE_TYPE_ULONG, BASE_TYPE_NONE },
+    { "sint32", BASE_TYPE_INT, BASE_TYPE_NONE },
+    { "sint64", BASE_TYPE_LONG, BASE_TYPE_NONE },
+    { "fixed32", BASE_TYPE_UINT, BASE_TYPE_NONE },
+    { "fixed64", BASE_TYPE_ULONG, BASE_TYPE_NONE },
+    { "sfixed32", BASE_TYPE_INT, BASE_TYPE_NONE },
+    { "sfixed64", BASE_TYPE_LONG, BASE_TYPE_NONE },
+    { "bool", BASE_TYPE_BOOL, BASE_TYPE_NONE },
+    { "string", BASE_TYPE_STRING, BASE_TYPE_NONE },
+    { "bytes", BASE_TYPE_VECTOR, BASE_TYPE_UCHAR },
+    { nullptr, BASE_TYPE_NONE, BASE_TYPE_NONE }
+  };
+  for (auto tl = lookup; tl->proto_type; tl++) {
+    if (attribute_ == tl->proto_type) {
+      type->base_type = tl->fb_type;
+      type->element = tl->element;
+      NEXT();
+      return NoError();
+    }
+  }
+  if (Is('.')) NEXT();  // qualified names may start with a . ?
+  ECHECK(ParseTypeIdent(*type));
+  return NoError();
+}
+
+CheckedError Parser::SkipAnyJsonValue() {
+  switch (token_) {
+    case '{': {
+      size_t fieldn_outer = 0;
+      return ParseTableDelimiters(
+          fieldn_outer, nullptr,
+          [&](const std::string &, size_t &fieldn,
+              const StructDef *) -> CheckedError {
+            ECHECK(Recurse([&]() { return SkipAnyJsonValue(); }));
+            fieldn++;
+            return NoError();
+          });
+    }
+    case '[': {
+      uoffset_t count = 0;
+      return ParseVectorDelimiters(count, [&](uoffset_t &) -> CheckedError {
+        return Recurse([&]() { return SkipAnyJsonValue(); });
+      });
+    }
+    case kTokenStringConstant:
+    case kTokenIntegerConstant:
+    case kTokenFloatConstant: NEXT(); break;
+    default:
+      if (IsIdent("true") || IsIdent("false") || IsIdent("null")) {
+        NEXT();
+      } else
+        return TokenError();
+  }
+  return NoError();
+}
+
+CheckedError Parser::ParseFlexBufferValue(flexbuffers::Builder *builder) {
+  switch (token_) {
+    case '{': {
+      auto start = builder->StartMap();
+      size_t fieldn_outer = 0;
+      auto err =
+          ParseTableDelimiters(fieldn_outer, nullptr,
+                               [&](const std::string &name, size_t &fieldn,
+                                   const StructDef *) -> CheckedError {
+                                 builder->Key(name);
+                                 ECHECK(ParseFlexBufferValue(builder));
+                                 fieldn++;
+                                 return NoError();
+                               });
+      ECHECK(err);
+      builder->EndMap(start);
+      break;
+    }
+    case '[': {
+      auto start = builder->StartVector();
+      uoffset_t count = 0;
+      ECHECK(ParseVectorDelimiters(count, [&](uoffset_t &) -> CheckedError {
+        return ParseFlexBufferValue(builder);
+      }));
+      builder->EndVector(start, false, false);
+      break;
+    }
+    case kTokenStringConstant:
+      builder->String(attribute_);
+      EXPECT(kTokenStringConstant);
+      break;
+    case kTokenIntegerConstant:
+      builder->Int(StringToInt(attribute_.c_str()));
+      EXPECT(kTokenIntegerConstant);
+      break;
+    case kTokenFloatConstant:
+      builder->Double(strtod(attribute_.c_str(), nullptr));
+      EXPECT(kTokenFloatConstant);
+      break;
+    default:
+      if (IsIdent("true")) {
+        builder->Bool(true);
+        NEXT();
+      } else if (IsIdent("false")) {
+        builder->Bool(false);
+        NEXT();
+      } else if (IsIdent("null")) {
+        builder->Null();
+        NEXT();
+      } else
+        return TokenError();
+  }
+  return NoError();
+}
+
+bool Parser::ParseFlexBuffer(const char *source, const char *source_filename,
+                             flexbuffers::Builder *builder) {
+  auto ok = !StartParseFile(source, source_filename).Check() &&
+            !ParseFlexBufferValue(builder).Check();
+  if (ok) builder->Finish();
+  return ok;
+}
+
+bool Parser::Parse(const char *source, const char **include_paths,
+                   const char *source_filename) {
+  FLATBUFFERS_ASSERT(0 == recurse_protection_counter);
+  auto r = !ParseRoot(source, include_paths, source_filename).Check();
+  FLATBUFFERS_ASSERT(0 == recurse_protection_counter);
+  return r;
+}
+
+CheckedError Parser::StartParseFile(const char *source,
+                                    const char *source_filename) {
+  file_being_parsed_ = source_filename ? source_filename : "";
+  source_ = source;
+  ResetState(source_);
+  error_.clear();
+  ECHECK(SkipByteOrderMark());
+  NEXT();
+  if (Is(kTokenEof)) return Error("input file is empty");
+  return NoError();
+}
+
+CheckedError Parser::ParseRoot(const char *source, const char **include_paths,
+                               const char *source_filename) {
+  ECHECK(DoParse(source, include_paths, source_filename, nullptr));
+
+  // Check that all types were defined.
+  for (auto it = structs_.vec.begin(); it != structs_.vec.end();) {
+    auto &struct_def = **it;
+    if (struct_def.predecl) {
+      if (opts.proto_mode) {
+        // Protos allow enums to be used before declaration, so check if that
+        // is the case here.
+        EnumDef *enum_def = nullptr;
+        for (size_t components =
+                 struct_def.defined_namespace->components.size() + 1;
+             components && !enum_def; components--) {
+          auto qualified_name =
+              struct_def.defined_namespace->GetFullyQualifiedName(
+                  struct_def.name, components - 1);
+          enum_def = LookupEnum(qualified_name);
+        }
+        if (enum_def) {
+          // This is pretty slow, but a simple solution for now.
+          auto initial_count = struct_def.refcount;
+          for (auto struct_it = structs_.vec.begin();
+               struct_it != structs_.vec.end(); ++struct_it) {
+            auto &sd = **struct_it;
+            for (auto field_it = sd.fields.vec.begin();
+                 field_it != sd.fields.vec.end(); ++field_it) {
+              auto &field = **field_it;
+              if (field.value.type.struct_def == &struct_def) {
+                field.value.type.struct_def = nullptr;
+                field.value.type.enum_def = enum_def;
+                auto &bt = field.value.type.base_type == BASE_TYPE_VECTOR
+                               ? field.value.type.element
+                               : field.value.type.base_type;
+                FLATBUFFERS_ASSERT(bt == BASE_TYPE_STRUCT);
+                bt = enum_def->underlying_type.base_type;
+                struct_def.refcount--;
+                enum_def->refcount++;
+              }
+            }
+          }
+          if (struct_def.refcount)
+            return Error("internal: " + NumToString(struct_def.refcount) + "/" +
+                         NumToString(initial_count) +
+                         " use(s) of pre-declaration enum not accounted for: " +
+                         enum_def->name);
+          structs_.dict.erase(structs_.dict.find(struct_def.name));
+          it = structs_.vec.erase(it);
+          delete &struct_def;
+          continue;  // Skip error.
+        }
+      }
+      auto err = "type referenced but not defined (check namespace): " +
+                 struct_def.name;
+      if (struct_def.original_location)
+        err += ", originally at: " + *struct_def.original_location;
+      return Error(err);
+    }
+    ++it;
+  }
+
+  // This check has to happen here and not earlier, because only now do we
+  // know for sure what the type of these are.
+  for (auto it = enums_.vec.begin(); it != enums_.vec.end(); ++it) {
+    auto &enum_def = **it;
+    if (enum_def.is_union) {
+      for (auto val_it = enum_def.Vals().begin();
+           val_it != enum_def.Vals().end(); ++val_it) {
+        auto &val = **val_it;
+        if (!SupportsAdvancedUnionFeatures() && val.union_type.struct_def &&
+            val.union_type.struct_def->fixed)
+          return Error(
+              "only tables can be union elements in the generated language: " +
+              val.name);
+      }
+    }
+  }
+  return NoError();
+}
+
+CheckedError Parser::DoParse(const char *source, const char **include_paths,
+                             const char *source_filename,
+                             const char *include_filename) {
+  if (source_filename) {
+    if (included_files_.find(source_filename) == included_files_.end()) {
+      included_files_[source_filename] =
+          include_filename ? include_filename : "";
+      files_included_per_file_[source_filename] = std::set<std::string>();
+    } else {
+      return NoError();
+    }
+  }
+  if (!include_paths) {
+    static const char *current_directory[] = { "", nullptr };
+    include_paths = current_directory;
+  }
+  field_stack_.clear();
+  builder_.Clear();
+  // Start with a blank namespace just in case this file doesn't have one.
+  current_namespace_ = empty_namespace_;
+
+  ECHECK(StartParseFile(source, source_filename));
+
+  // Includes must come before type declarations:
+  for (;;) {
+    // Parse pre-include proto statements if any:
+    if (opts.proto_mode && (attribute_ == "option" || attribute_ == "syntax" ||
+                            attribute_ == "package")) {
+      ECHECK(ParseProtoDecl());
+    } else if (IsIdent("native_include")) {
+      NEXT();
+      vector_emplace_back(&native_included_files_, attribute_);
+      EXPECT(kTokenStringConstant);
+      EXPECT(';');
+    } else if (IsIdent("include") || (opts.proto_mode && IsIdent("import"))) {
+      NEXT();
+      if (opts.proto_mode && attribute_ == "public") NEXT();
+      auto name = flatbuffers::PosixPath(attribute_.c_str());
+      EXPECT(kTokenStringConstant);
+      // Look for the file in include_paths.
+      std::string filepath;
+      for (auto paths = include_paths; paths && *paths; paths++) {
+        filepath = flatbuffers::ConCatPathFileName(*paths, name);
+        if (FileExists(filepath.c_str())) break;
+      }
+      if (filepath.empty())
+        return Error("unable to locate include file: " + name);
+      if (source_filename)
+        files_included_per_file_[source_filename].insert(filepath);
+      if (included_files_.find(filepath) == included_files_.end()) {
+        // We found an include file that we have not parsed yet.
+        // Load it and parse it.
+        std::string contents;
+        if (!LoadFile(filepath.c_str(), true, &contents))
+          return Error("unable to load include file: " + name);
+        ECHECK(DoParse(contents.c_str(), include_paths, filepath.c_str(),
+                       name.c_str()));
+        // We generally do not want to output code for any included files:
+        if (!opts.generate_all) MarkGenerated();
+        // Reset these just in case the included file had them, and the
+        // parent doesn't.
+        root_struct_def_ = nullptr;
+        file_identifier_.clear();
+        file_extension_.clear();
+        // This is the easiest way to continue this file after an include:
+        // instead of saving and restoring all the state, we simply start the
+        // file anew. This will cause it to encounter the same include
+        // statement again, but this time it will skip it, because it was
+        // entered into included_files_.
+        // This is recursive, but only go as deep as the number of include
+        // statements.
+        if (source_filename) {
+          included_files_.erase(source_filename);
+        }
+        return DoParse(source, include_paths, source_filename,
+                       include_filename);
+      }
+      EXPECT(';');
+    } else {
+      break;
+    }
+  }
+  // Now parse all other kinds of declarations:
+  while (token_ != kTokenEof) {
+    if (opts.proto_mode) {
+      ECHECK(ParseProtoDecl());
+    } else if (IsIdent("namespace")) {
+      ECHECK(ParseNamespace());
+    } else if (token_ == '{') {
+      if (!root_struct_def_)
+        return Error("no root type set to parse json with");
+      if (builder_.GetSize()) {
+        return Error("cannot have more than one json object in a file");
+      }
+      uoffset_t toff;
+      ECHECK(ParseTable(*root_struct_def_, nullptr, &toff));
+      if (opts.size_prefixed) {
+        builder_.FinishSizePrefixed(Offset<Table>(toff), file_identifier_.length()
+                                                             ? file_identifier_.c_str()
+                                                             : nullptr);
+      } else {
+        builder_.Finish(Offset<Table>(toff), file_identifier_.length()
+                                                 ? file_identifier_.c_str()
+                                                 : nullptr);
+      }
+      // Check that JSON file doesn't contain more objects or IDL directives.
+      // Comments after JSON are allowed.
+      EXPECT(kTokenEof);
+    } else if (IsIdent("enum")) {
+      ECHECK(ParseEnum(false, nullptr));
+    } else if (IsIdent("union")) {
+      ECHECK(ParseEnum(true, nullptr));
+    } else if (IsIdent("root_type")) {
+      NEXT();
+      auto root_type = attribute_;
+      EXPECT(kTokenIdentifier);
+      ECHECK(ParseNamespacing(&root_type, nullptr));
+      if (opts.root_type.empty()) {
+        if (!SetRootType(root_type.c_str()))
+          return Error("unknown root type: " + root_type);
+        if (root_struct_def_->fixed)
+          return Error("root type must be a table");
+      }
+      EXPECT(';');
+    } else if (IsIdent("file_identifier")) {
+      NEXT();
+      file_identifier_ = attribute_;
+      EXPECT(kTokenStringConstant);
+      if (file_identifier_.length() != FlatBufferBuilder::kFileIdentifierLength)
+        return Error("file_identifier must be exactly " +
+                     NumToString(FlatBufferBuilder::kFileIdentifierLength) +
+                     " characters");
+      EXPECT(';');
+    } else if (IsIdent("file_extension")) {
+      NEXT();
+      file_extension_ = attribute_;
+      EXPECT(kTokenStringConstant);
+      EXPECT(';');
+    } else if (IsIdent("include")) {
+      return Error("includes must come before declarations");
+    } else if (IsIdent("attribute")) {
+      NEXT();
+      auto name = attribute_;
+      if (Is(kTokenIdentifier)) {
+        NEXT();
+      } else {
+        EXPECT(kTokenStringConstant);
+      }
+      EXPECT(';');
+      known_attributes_[name] = false;
+    } else if (IsIdent("rpc_service")) {
+      ECHECK(ParseService());
+    } else {
+      ECHECK(ParseDecl());
+    }
+  }
+  return NoError();
+}
+
+std::set<std::string> Parser::GetIncludedFilesRecursive(
+    const std::string &file_name) const {
+  std::set<std::string> included_files;
+  std::list<std::string> to_process;
+
+  if (file_name.empty()) return included_files;
+  to_process.push_back(file_name);
+
+  while (!to_process.empty()) {
+    std::string current = to_process.front();
+    to_process.pop_front();
+    included_files.insert(current);
+
+    // Workaround the lack of const accessor in C++98 maps.
+    auto &new_files =
+        (*const_cast<std::map<std::string, std::set<std::string>> *>(
+            &files_included_per_file_))[current];
+    for (auto it = new_files.begin(); it != new_files.end(); ++it) {
+      if (included_files.find(*it) == included_files.end())
+        to_process.push_back(*it);
+    }
+  }
+
+  return included_files;
+}
+
+// Schema serialization functionality:
+
+template<typename T> bool compareName(const T *a, const T *b) {
+  return a->defined_namespace->GetFullyQualifiedName(a->name) <
+         b->defined_namespace->GetFullyQualifiedName(b->name);
+}
+
+template<typename T> void AssignIndices(const std::vector<T *> &defvec) {
+  // Pre-sort these vectors, such that we can set the correct indices for them.
+  auto vec = defvec;
+  std::sort(vec.begin(), vec.end(), compareName<T>);
+  for (int i = 0; i < static_cast<int>(vec.size()); i++) vec[i]->index = i;
+}
+
+void Parser::Serialize() {
+  builder_.Clear();
+  AssignIndices(structs_.vec);
+  AssignIndices(enums_.vec);
+  std::vector<Offset<reflection::Object>> object_offsets;
+  for (auto it = structs_.vec.begin(); it != structs_.vec.end(); ++it) {
+    auto offset = (*it)->Serialize(&builder_, *this);
+    object_offsets.push_back(offset);
+    (*it)->serialized_location = offset.o;
+  }
+  std::vector<Offset<reflection::Enum>> enum_offsets;
+  for (auto it = enums_.vec.begin(); it != enums_.vec.end(); ++it) {
+    auto offset = (*it)->Serialize(&builder_, *this);
+    enum_offsets.push_back(offset);
+    (*it)->serialized_location = offset.o;
+  }
+  std::vector<Offset<reflection::Service>> service_offsets;
+  for (auto it = services_.vec.begin(); it != services_.vec.end(); ++it) {
+    auto offset = (*it)->Serialize(&builder_, *this);
+    service_offsets.push_back(offset);
+    (*it)->serialized_location = offset.o;
+  }
+  auto objs__ = builder_.CreateVectorOfSortedTables(&object_offsets);
+  auto enum__ = builder_.CreateVectorOfSortedTables(&enum_offsets);
+  auto fiid__ = builder_.CreateString(file_identifier_);
+  auto fext__ = builder_.CreateString(file_extension_);
+  auto serv__ = builder_.CreateVectorOfSortedTables(&service_offsets);
+  auto schema_offset =
+      reflection::CreateSchema(builder_, objs__, enum__, fiid__, fext__,
+        (root_struct_def_ ? root_struct_def_->serialized_location : 0),
+        serv__);
+  if (opts.size_prefixed) {
+    builder_.FinishSizePrefixed(schema_offset, reflection::SchemaIdentifier());
+  } else {
+    builder_.Finish(schema_offset, reflection::SchemaIdentifier());
+  }
+}
+
+static Namespace *GetNamespace(
+    const std::string &qualified_name, std::vector<Namespace *> &namespaces,
+    std::map<std::string, Namespace *> &namespaces_index) {
+  size_t dot = qualified_name.find_last_of('.');
+  std::string namespace_name = (dot != std::string::npos)
+                                   ? std::string(qualified_name.c_str(), dot)
+                                   : "";
+  Namespace *&ns = namespaces_index[namespace_name];
+
+  if (!ns) {
+    ns = new Namespace();
+    namespaces.push_back(ns);
+
+    size_t pos = 0;
+
+    for (;;) {
+      dot = qualified_name.find('.', pos);
+      if (dot == std::string::npos) { break; }
+      ns->components.push_back(qualified_name.substr(pos, dot - pos));
+      pos = dot + 1;
+    }
+  }
+
+  return ns;
+}
+
+Offset<reflection::Object> StructDef::Serialize(FlatBufferBuilder *builder,
+                                                const Parser &parser) const {
+  std::vector<Offset<reflection::Field>> field_offsets;
+  for (auto it = fields.vec.begin(); it != fields.vec.end(); ++it) {
+    field_offsets.push_back((*it)->Serialize(
+        builder, static_cast<uint16_t>(it - fields.vec.begin()), parser));
+  }
+  auto qualified_name = defined_namespace->GetFullyQualifiedName(name);
+  auto name__ = builder->CreateString(qualified_name);
+  auto flds__ = builder->CreateVectorOfSortedTables(&field_offsets);
+  auto attr__ = SerializeAttributes(builder, parser);
+  auto docs__ = parser.opts.binary_schema_comments
+                ? builder->CreateVectorOfStrings(doc_comment)
+                : 0;
+  return reflection::CreateObject(*builder, name__, flds__, fixed,
+                                  static_cast<int>(minalign),
+                                  static_cast<int>(bytesize),
+                                  attr__, docs__);
+}
+
+bool StructDef::Deserialize(Parser &parser, const reflection::Object *object) {
+  if (!DeserializeAttributes(parser, object->attributes()))
+    return false;
+  DeserializeDoc(doc_comment, object->documentation());
+  name = parser.UnqualifiedName(object->name()->str());
+  predecl = false;
+  sortbysize = attributes.Lookup("original_order") == nullptr && !fixed;
+  const auto& of = *(object->fields());
+  auto indexes = std::vector<uoffset_t>(of.size());
+  for (uoffset_t i = 0; i < of.size(); i++) indexes[of.Get(i)->id()] = i;
+  size_t tmp_struct_size = 0;
+  for (size_t i = 0; i < indexes.size(); i++) {
+    auto field = of.Get(indexes[i]);
+    auto field_def = new FieldDef();
+    if (!field_def->Deserialize(parser, field) ||
+        fields.Add(field_def->name, field_def)) {
+      delete field_def;
+      return false;
+    }
+    if (fixed) {
+      // Recompute padding since that's currently not serialized.
+      auto size = InlineSize(field_def->value.type);
+      auto next_field =
+          i + 1 < indexes.size()
+          ? of.Get(indexes[i+1])
+          : nullptr;
+      tmp_struct_size += size;
+      field_def->padding =
+          next_field ? (next_field->offset() - field_def->value.offset) - size
+                     : PaddingBytes(tmp_struct_size, minalign);
+      tmp_struct_size += field_def->padding;
+    }
+  }
+  FLATBUFFERS_ASSERT(static_cast<int>(tmp_struct_size) == object->bytesize());
+  return true;
+}
+
+Offset<reflection::Field> FieldDef::Serialize(FlatBufferBuilder *builder,
+                                              uint16_t id,
+                                              const Parser &parser) const {
+  auto name__ = builder->CreateString(name);
+  auto type__ = value.type.Serialize(builder);
+  auto attr__ = SerializeAttributes(builder, parser);
+  auto docs__ = parser.opts.binary_schema_comments
+                ? builder->CreateVectorOfStrings(doc_comment)
+                : 0;
+  return reflection::CreateField(*builder, name__, type__, id, value.offset,
+      // Is uint64>max(int64) tested?
+      IsInteger(value.type.base_type) ? StringToInt(value.constant.c_str()) : 0,
+      // result may be platform-dependent if underlying is float (not double)
+      IsFloat(value.type.base_type) ? strtod(value.constant.c_str(), nullptr)
+                                    : 0.0,
+      deprecated, required, key, attr__, docs__);
+  // TODO: value.constant is almost always "0", we could save quite a bit of
+  // space by sharing it. Same for common values of value.type.
+}
+
+bool FieldDef::Deserialize(Parser &parser, const reflection::Field *field) {
+  name = field->name()->str();
+  defined_namespace = parser.current_namespace_;
+  if (!value.type.Deserialize(parser, field->type()))
+    return false;
+  value.offset = field->offset();
+  if (IsInteger(value.type.base_type)) {
+    value.constant = NumToString(field->default_integer());
+  } else if (IsFloat(value.type.base_type)) {
+    value.constant = FloatToString(field->default_real(), 16);
+    size_t last_zero = value.constant.find_last_not_of('0');
+    if (last_zero != std::string::npos && last_zero != 0) {
+      value.constant.erase(last_zero, std::string::npos);
+    }
+  }
+  deprecated = field->deprecated();
+  required = field->required();
+  key = field->key();
+  if (!DeserializeAttributes(parser, field->attributes()))
+    return false;
+  // TODO: this should probably be handled by a separate attribute
+  if (attributes.Lookup("flexbuffer")) {
+    flexbuffer = true;
+    parser.uses_flexbuffers_ = true;
+    if (value.type.base_type != BASE_TYPE_VECTOR ||
+        value.type.element != BASE_TYPE_UCHAR)
+      return false;
+  }
+  if (auto nested = attributes.Lookup("nested_flatbuffer")) {
+    auto nested_qualified_name =
+        parser.current_namespace_->GetFullyQualifiedName(nested->constant);
+    nested_flatbuffer = parser.LookupStruct(nested_qualified_name);
+    if (!nested_flatbuffer) return false;
+  }
+  DeserializeDoc(doc_comment, field->documentation());
+  return true;
+}
+
+Offset<reflection::RPCCall> RPCCall::Serialize(FlatBufferBuilder *builder,
+                                               const Parser &parser) const {
+  auto name__ = builder->CreateString(name);
+  auto attr__ = SerializeAttributes(builder, parser);
+  auto docs__ = parser.opts.binary_schema_comments
+                ? builder->CreateVectorOfStrings(doc_comment)
+                : 0;
+  return reflection::CreateRPCCall(*builder, name__,
+                                   request->serialized_location,
+                                   response->serialized_location,
+                                   attr__, docs__);
+}
+
+bool RPCCall::Deserialize(Parser &parser, const reflection::RPCCall *call) {
+  name = call->name()->str();
+  if (!DeserializeAttributes(parser, call->attributes()))
+    return false;
+  DeserializeDoc(doc_comment, call->documentation());
+  request = parser.structs_.Lookup(call->request()->name()->str());
+  response = parser.structs_.Lookup(call->response()->name()->str());
+  if (!request || !response) { return false; }
+  return true;
+}
+
+Offset<reflection::Service> ServiceDef::Serialize(FlatBufferBuilder *builder,
+                                                  const Parser &parser) const {
+  std::vector<Offset<reflection::RPCCall>> servicecall_offsets;
+  for (auto it = calls.vec.begin(); it != calls.vec.end(); ++it) {
+    servicecall_offsets.push_back((*it)->Serialize(builder, parser));
+  }
+  auto qualified_name = defined_namespace->GetFullyQualifiedName(name);
+  auto name__ = builder->CreateString(qualified_name);
+  auto call__ = builder->CreateVector(servicecall_offsets);
+  auto attr__ = SerializeAttributes(builder, parser);
+  auto docs__ = parser.opts.binary_schema_comments
+                ? builder->CreateVectorOfStrings(doc_comment)
+                : 0;
+  return reflection::CreateService(*builder, name__, call__, attr__, docs__);
+}
+
+bool ServiceDef::Deserialize(Parser &parser,
+                             const reflection::Service *service) {
+  name = parser.UnqualifiedName(service->name()->str());
+  if (service->calls()) {
+    for (uoffset_t i = 0; i < service->calls()->size(); ++i) {
+      auto call = new RPCCall();
+      if (!call->Deserialize(parser, service->calls()->Get(i)) ||
+          calls.Add(call->name, call)) {
+        delete call;
+        return false;
+      }
+    }
+  }
+  if (!DeserializeAttributes(parser, service->attributes()))
+    return false;
+  DeserializeDoc(doc_comment, service->documentation());
+  return true;
+}
+
+Offset<reflection::Enum> EnumDef::Serialize(FlatBufferBuilder *builder,
+                                            const Parser &parser) const {
+  std::vector<Offset<reflection::EnumVal>> enumval_offsets;
+  for (auto it = vals.vec.begin(); it != vals.vec.end(); ++it) {
+    enumval_offsets.push_back((*it)->Serialize(builder, parser));
+  }
+  auto qualified_name = defined_namespace->GetFullyQualifiedName(name);
+  auto name__ = builder->CreateString(qualified_name);
+  auto vals__ = builder->CreateVector(enumval_offsets);
+  auto type__ = underlying_type.Serialize(builder);
+  auto attr__ = SerializeAttributes(builder, parser);
+  auto docs__ = parser.opts.binary_schema_comments
+                ? builder->CreateVectorOfStrings(doc_comment)
+                : 0;
+  return reflection::CreateEnum(*builder, name__, vals__, is_union, type__,
+                                attr__, docs__);
+}
+
+bool EnumDef::Deserialize(Parser &parser, const reflection::Enum *_enum) {
+  name = parser.UnqualifiedName(_enum->name()->str());
+  for (uoffset_t i = 0; i < _enum->values()->size(); ++i) {
+    auto val = new EnumVal();
+    if (!val->Deserialize(parser, _enum->values()->Get(i)) ||
+        vals.Add(val->name, val)) {
+      delete val;
+      return false;
+    }
+  }
+  is_union = _enum->is_union();
+  if (!underlying_type.Deserialize(parser, _enum->underlying_type())) {
+    return false;
+  }
+  if (!DeserializeAttributes(parser, _enum->attributes()))
+    return false;
+  DeserializeDoc(doc_comment, _enum->documentation());
+  return true;
+}
+
+Offset<reflection::EnumVal> EnumVal::Serialize(FlatBufferBuilder *builder,
+                                               const Parser &parser) const {
+  auto name__ = builder->CreateString(name);
+  auto type__ = union_type.Serialize(builder);
+  auto docs__ = parser.opts.binary_schema_comments
+                ? builder->CreateVectorOfStrings(doc_comment)
+                : 0;
+  return reflection::CreateEnumVal(*builder, name__, value,
+      union_type.struct_def ? union_type.struct_def->serialized_location : 0,
+      type__, docs__);
+}
+
+bool EnumVal::Deserialize(const Parser &parser,
+                          const reflection::EnumVal *val) {
+  name = val->name()->str();
+  value = val->value();
+  if (!union_type.Deserialize(parser, val->union_type()))
+    return false;
+  DeserializeDoc(doc_comment, val->documentation());
+  return true;
+}
+
+Offset<reflection::Type> Type::Serialize(FlatBufferBuilder *builder) const {
+  return reflection::CreateType(
+      *builder, static_cast<reflection::BaseType>(base_type),
+      static_cast<reflection::BaseType>(element),
+      struct_def ? struct_def->index : (enum_def ? enum_def->index : -1),
+      fixed_length);
+}
+
+bool Type::Deserialize(const Parser &parser, const reflection::Type *type) {
+  if (type == nullptr) return true;
+  base_type = static_cast<BaseType>(type->base_type());
+  element = static_cast<BaseType>(type->element());
+  fixed_length = type->fixed_length();
+  if (type->index() >= 0) {
+    bool is_series = type->base_type() == reflection::Vector ||
+                     type->base_type() == reflection::Array;
+    if (type->base_type() == reflection::Obj ||
+        (is_series &&
+         type->element() == reflection::Obj)) {
+      if (static_cast<size_t>(type->index()) < parser.structs_.vec.size()) {
+        struct_def = parser.structs_.vec[type->index()];
+        struct_def->refcount++;
+      } else {
+        return false;
+      }
+    } else {
+      if (static_cast<size_t>(type->index()) < parser.enums_.vec.size()) {
+        enum_def = parser.enums_.vec[type->index()];
+      } else {
+        return false;
+      }
+    }
+  }
+  return true;
+}
+
+flatbuffers::Offset<
+    flatbuffers::Vector<flatbuffers::Offset<reflection::KeyValue>>>
+Definition::SerializeAttributes(FlatBufferBuilder *builder,
+                                const Parser &parser) const {
+  std::vector<flatbuffers::Offset<reflection::KeyValue>> attrs;
+  for (auto kv = attributes.dict.begin(); kv != attributes.dict.end(); ++kv) {
+    auto it = parser.known_attributes_.find(kv->first);
+    FLATBUFFERS_ASSERT(it != parser.known_attributes_.end());
+    if (parser.opts.binary_schema_builtins || !it->second) {
+      auto key = builder->CreateString(kv->first);
+      auto val = builder->CreateString(kv->second->constant);
+      attrs.push_back(reflection::CreateKeyValue(*builder, key, val));
+    }
+  }
+  if (attrs.size()) {
+    return builder->CreateVectorOfSortedTables(&attrs);
+  } else {
+    return 0;
+  }
+}
+
+bool Definition::DeserializeAttributes(
+    Parser &parser, const Vector<Offset<reflection::KeyValue>> *attrs) {
+  if (attrs == nullptr)
+    return true;
+  for (uoffset_t i = 0; i < attrs->size(); ++i) {
+    auto kv = attrs->Get(i);
+    auto value = new Value();
+    if (kv->value()) { value->constant = kv->value()->str(); }
+    if (attributes.Add(kv->key()->str(), value)) {
+      delete value;
+      return false;
+    }
+    parser.known_attributes_[kv->key()->str()];
+  }
+  return true;
+}
+
+/************************************************************************/
+/* DESERIALIZATION                                                      */
+/************************************************************************/
+bool Parser::Deserialize(const uint8_t *buf, const size_t size) {
+  flatbuffers::Verifier verifier(reinterpret_cast<const uint8_t *>(buf), size);
+  bool size_prefixed = false;
+  if(!reflection::SchemaBufferHasIdentifier(buf)) {
+    if (!flatbuffers::BufferHasIdentifier(buf, reflection::SchemaIdentifier(),
+                                          true))
+      return false;
+    else
+      size_prefixed = true;
+  }
+  auto verify_fn = size_prefixed ? &reflection::VerifySizePrefixedSchemaBuffer
+                                 : &reflection::VerifySchemaBuffer;
+  if (!verify_fn(verifier)) {
+    return false;
+  }
+  auto schema = size_prefixed ? reflection::GetSizePrefixedSchema(buf)
+                              : reflection::GetSchema(buf);
+  return Deserialize(schema);
+}
+
+bool Parser::Deserialize(const reflection::Schema *schema) {
+  file_identifier_ = schema->file_ident() ? schema->file_ident()->str() : "";
+  file_extension_ = schema->file_ext() ? schema->file_ext()->str() : "";
+  std::map<std::string, Namespace *> namespaces_index;
+
+  // Create defs without deserializing so references from fields to structs and
+  // enums can be resolved.
+  for (auto it = schema->objects()->begin(); it != schema->objects()->end();
+       ++it) {
+    auto struct_def = new StructDef();
+    struct_def->bytesize = it->bytesize();
+    struct_def->fixed = it->is_struct();
+    struct_def->minalign = it->minalign();
+    if (structs_.Add(it->name()->str(), struct_def)) {
+      delete struct_def;
+      return false;
+    }
+    auto type = new Type(BASE_TYPE_STRUCT, struct_def, nullptr);
+    if (types_.Add(it->name()->str(), type)) {
+      delete type;
+      return false;
+    }
+  }
+  for (auto it = schema->enums()->begin(); it != schema->enums()->end(); ++it) {
+    auto enum_def = new EnumDef();
+    if (enums_.Add(it->name()->str(), enum_def)) {
+      delete enum_def;
+      return false;
+    }
+    auto type = new Type(BASE_TYPE_UNION, nullptr, enum_def);
+    if (types_.Add(it->name()->str(), type)) {
+      delete type;
+      return false;
+    }
+  }
+
+  // Now fields can refer to structs and enums by index.
+  for (auto it = schema->objects()->begin(); it != schema->objects()->end();
+       ++it) {
+    std::string qualified_name = it->name()->str();
+    auto struct_def = structs_.Lookup(qualified_name);
+    struct_def->defined_namespace =
+        GetNamespace(qualified_name, namespaces_, namespaces_index);
+    if (!struct_def->Deserialize(*this, * it)) { return false; }
+    if (schema->root_table() == *it) { root_struct_def_ = struct_def; }
+  }
+  for (auto it = schema->enums()->begin(); it != schema->enums()->end(); ++it) {
+    std::string qualified_name = it->name()->str();
+    auto enum_def = enums_.Lookup(qualified_name);
+    enum_def->defined_namespace =
+        GetNamespace(qualified_name, namespaces_, namespaces_index);
+    if (!enum_def->Deserialize(*this, *it)) { return false; }
+  }
+
+  if (schema->services()) {
+    for (auto it = schema->services()->begin(); it != schema->services()->end();
+         ++it) {
+      std::string qualified_name = it->name()->str();
+      auto service_def = new ServiceDef();
+      service_def->defined_namespace =
+          GetNamespace(qualified_name, namespaces_, namespaces_index);
+      if (!service_def->Deserialize(*this, *it) ||
+          services_.Add(qualified_name, service_def)) {
+        delete service_def;
+        return false;
+      }
+    }
+  }
+
+  return true;
+}
+
+std::string Parser::ConformTo(const Parser &base) {
+  for (auto sit = structs_.vec.begin(); sit != structs_.vec.end(); ++sit) {
+    auto &struct_def = **sit;
+    auto qualified_name =
+        struct_def.defined_namespace->GetFullyQualifiedName(struct_def.name);
+    auto struct_def_base = base.LookupStruct(qualified_name);
+    if (!struct_def_base) continue;
+    for (auto fit = struct_def.fields.vec.begin();
+         fit != struct_def.fields.vec.end(); ++fit) {
+      auto &field = **fit;
+      auto field_base = struct_def_base->fields.Lookup(field.name);
+      if (field_base) {
+        if (field.value.offset != field_base->value.offset)
+          return "offsets differ for field: " + field.name;
+        if (field.value.constant != field_base->value.constant)
+          return "defaults differ for field: " + field.name;
+        if (!EqualByName(field.value.type, field_base->value.type))
+          return "types differ for field: " + field.name;
+      } else {
+        // Doesn't have to exist, deleting fields is fine.
+        // But we should check if there is a field that has the same offset
+        // but is incompatible (in the case of field renaming).
+        for (auto fbit = struct_def_base->fields.vec.begin();
+             fbit != struct_def_base->fields.vec.end(); ++fbit) {
+          field_base = *fbit;
+          if (field.value.offset == field_base->value.offset) {
+            if (!EqualByName(field.value.type, field_base->value.type))
+              return "field renamed to different type: " + field.name;
+            break;
+          }
+        }
+      }
+    }
+  }
+  for (auto eit = enums_.vec.begin(); eit != enums_.vec.end(); ++eit) {
+    auto &enum_def = **eit;
+    auto qualified_name =
+        enum_def.defined_namespace->GetFullyQualifiedName(enum_def.name);
+    auto enum_def_base = base.enums_.Lookup(qualified_name);
+    if (!enum_def_base) continue;
+    for (auto evit = enum_def.Vals().begin(); evit != enum_def.Vals().end();
+         ++evit) {
+      auto &enum_val = **evit;
+      auto enum_val_base = enum_def_base->Lookup(enum_val.name);
+      if (enum_val_base) {
+        if (enum_val != *enum_val_base)
+          return "values differ for enum: " + enum_val.name;
+      }
+    }
+  }
+  return "";
+}
+
+}  // namespace flatbuffers