text: #include <Python.h>
  
  #include "pegen.h"
  #include "string_parser.h"
  
  static PyObject *
  _create_dummy_identifier(Parser *p)
  {
      return _PyPegen_new_identifier(p, "");
  }
  
  void *
  _PyPegen_dummy_name(Parser *p, ...)
  {
      static void *cache = NULL;
  
      if (cache != NULL) {
          return cache;
      }
  
      PyObject *id = _create_dummy_identifier(p);
      if (!id) {
          return NULL;
      }
      cache = _PyAST_Name(id, Load, 1, 0, 1, 0, p->arena);
      return cache;
  }
  
  /* Creates a single-element asdl_seq* that contains a */
  asdl_seq *
  _PyPegen_singleton_seq(Parser *p, void *a)
  {
      assert(a != NULL);
      asdl_seq *seq = (asdl_seq*)_Py_asdl_generic_seq_new(1, p->arena);
      if (!seq) {
          return NULL;
      }
      asdl_seq_SET_UNTYPED(seq, 0, a);
      return seq;
  }
  
  /* Creates a copy of seq and prepends a to it */
  asdl_seq *
  _PyPegen_seq_insert_in_front(Parser *p, void *a, asdl_seq *seq)
  {
      assert(a != NULL);
      if (!seq) {
          return _PyPegen_singleton_seq(p, a);
      }
  
      asdl_seq *new_seq = (asdl_seq*)_Py_asdl_generic_seq_new(asdl_seq_LEN(seq) + 1, p->arena);
      if (!new_seq) {
          return NULL;
      }
  
      asdl_seq_SET_UNTYPED(new_seq, 0, a);
      for (Py_ssize_t i = 1, l = asdl_seq_LEN(new_seq); i < l; i++) {
          asdl_seq_SET_UNTYPED(new_seq, i, asdl_seq_GET_UNTYPED(seq, i - 1));
      }
      return new_seq;
  }
  
  /* Creates a copy of seq and appends a to it */
  asdl_seq *
  _PyPegen_seq_append_to_end(Parser *p, asdl_seq *seq, void *a)
  {
      assert(a != NULL);
      if (!seq) {
          return _PyPegen_singleton_seq(p, a);
      }
  
      asdl_seq *new_seq = (asdl_seq*)_Py_asdl_generic_seq_new(asdl_seq_LEN(seq) + 1, p->arena);
      if (!new_seq) {
          return NULL;
      }
  
      for (Py_ssize_t i = 0, l = asdl_seq_LEN(new_seq); i + 1 < l; i++) {
          asdl_seq_SET_UNTYPED(new_seq, i, asdl_seq_GET_UNTYPED(seq, i));
      }
      asdl_seq_SET_UNTYPED(new_seq, asdl_seq_LEN(new_seq) - 1, a);
      return new_seq;
  }
  
  static Py_ssize_t
  _get_flattened_seq_size(asdl_seq *seqs)
  {
      Py_ssize_t size = 0;
      for (Py_ssize_t i = 0, l = asdl_seq_LEN(seqs); i < l; i++) {
          asdl_seq *inner_seq = asdl_seq_GET_UNTYPED(seqs, i);
          size += asdl_seq_LEN(inner_seq);
      }
      return size;
  }
  
  /* Flattens an asdl_seq* of asdl_seq*s */
  asdl_seq *
  _PyPegen_seq_flatten(Parser *p, asdl_seq *seqs)
  {
      Py_ssize_t flattened_seq_size = _get_flattened_seq_size(seqs);
      assert(flattened_seq_size > 0);
  
      asdl_seq *flattened_seq = (asdl_seq*)_Py_asdl_generic_seq_new(flattened_seq_size, p->arena);
      if (!flattened_seq) {
          return NULL;
      }
  
      int flattened_seq_idx = 0;
      for (Py_ssize_t i = 0, l = asdl_seq_LEN(seqs); i < l; i++) {
          asdl_seq *inner_seq = asdl_seq_GET_UNTYPED(seqs, i);
          for (Py_ssize_t j = 0, li = asdl_seq_LEN(inner_seq); j < li; j++) {
              asdl_seq_SET_UNTYPED(flattened_seq, flattened_seq_idx++, asdl_seq_GET_UNTYPED(inner_seq, j));
          }
      }
      assert(flattened_seq_idx == flattened_seq_size);
  
      return flattened_seq;
  }
  
  void *
  _PyPegen_seq_last_item(asdl_seq *seq)
  {
      Py_ssize_t len = asdl_seq_LEN(seq);
      return asdl_seq_GET_UNTYPED(seq, len - 1);
  }
  
  void *
  _PyPegen_seq_first_item(asdl_seq *seq)
  {
      return asdl_seq_GET_UNTYPED(seq, 0);
  }
  
  /* Creates a new name of the form <first_name>.<second_name> */
  expr_ty
  _PyPegen_join_names_with_dot(Parser *p, expr_ty first_name, expr_ty second_name)
  {
      assert(first_name != NULL && second_name != NULL);
      PyObject *first_identifier = first_name->v.Name.id;
      PyObject *second_identifier = second_name->v.Name.id;
  
      if (PyUnicode_READY(first_identifier) == -1) {
          return NULL;
      }
      if (PyUnicode_READY(second_identifier) == -1) {
          return NULL;
      }
      const char *first_str = PyUnicode_AsUTF8(first_identifier);
      if (!first_str) {
          return NULL;
      }
      const char *second_str = PyUnicode_AsUTF8(second_identifier);
      if (!second_str) {
          return NULL;
      }
      Py_ssize_t len = strlen(first_str) + strlen(second_str) + 1;  // +1 for the dot
  
      PyObject *str = PyBytes_FromStringAndSize(NULL, len);
      if (!str) {
          return NULL;
      }
  
      char *s = PyBytes_AS_STRING(str);
      if (!s) {
          return NULL;
      }
  
      strcpy(s, first_str);
      s += strlen(first_str);
      *s++ = '.';
      strcpy(s, second_str);
      s += strlen(second_str);
      *s = '\0';
  
      PyObject *uni = PyUnicode_DecodeUTF8(PyBytes_AS_STRING(str), PyBytes_GET_SIZE(str), NULL);
      Py_DECREF(str);
      if (!uni) {
          return NULL;
      }
      PyUnicode_InternInPlace(&uni);
      if (_PyArena_AddPyObject(p->arena, uni) < 0) {
          Py_DECREF(uni);
          return NULL;
      }
  
      return _PyAST_Name(uni, Load, EXTRA_EXPR(first_name, second_name));
  }
  
  /* Counts the total number of dots in seq's tokens */
  int
  _PyPegen_seq_count_dots(asdl_seq *seq)
  {
      int number_of_dots = 0;
      for (Py_ssize_t i = 0, l = asdl_seq_LEN(seq); i < l; i++) {
          Token *current_expr = asdl_seq_GET_UNTYPED(seq, i);
          switch (current_expr->type) {
              case ELLIPSIS:
                  number_of_dots += 3;
                  break;
              case DOT:
                  number_of_dots += 1;
                  break;
              default:
                  Py_UNREACHABLE();
          }
      }
  
      return number_of_dots;
  }
  
  /* Creates an alias with '*' as the identifier name */
  alias_ty
  _PyPegen_alias_for_star(Parser *p, int lineno, int col_offset, int end_lineno,
                          int end_col_offset, PyArena *arena) {
      PyObject *str = PyUnicode_InternFromString("*");
      if (!str) {
          return NULL;
      }
      if (_PyArena_AddPyObject(p->arena, str) < 0) {
          Py_DECREF(str);
          return NULL;
      }
      return _PyAST_alias(str, NULL, lineno, col_offset, end_lineno, end_col_offset, arena);
  }
  
  /* Creates a new asdl_seq* with the identifiers of all the names in seq */
  asdl_identifier_seq *
  _PyPegen_map_names_to_ids(Parser *p, asdl_expr_seq *seq)
  {
      Py_ssize_t len = asdl_seq_LEN(seq);
      assert(len > 0);
  
      asdl_identifier_seq *new_seq = _Py_asdl_identifier_seq_new(len, p->arena);
      if (!new_seq) {
          return NULL;
      }
      for (Py_ssize_t i = 0; i < len; i++) {
          expr_ty e = asdl_seq_GET(seq, i);
          asdl_seq_SET(new_seq, i, e->v.Name.id);
      }
      return new_seq;
  }
  
  /* Constructs a CmpopExprPair */
  CmpopExprPair *
  _PyPegen_cmpop_expr_pair(Parser *p, cmpop_ty cmpop, expr_ty expr)
  {
      assert(expr != NULL);
      CmpopExprPair *a = _PyArena_Malloc(p->arena, sizeof(CmpopExprPair));
      if (!a) {
          return NULL;
      }
      a->cmpop = cmpop;
      a->expr = expr;
      return a;
  }
  
  asdl_int_seq *
  _PyPegen_get_cmpops(Parser *p, asdl_seq *seq)
  {
      Py_ssize_t len = asdl_seq_LEN(seq);
      assert(len > 0);
  
      asdl_int_seq *new_seq = _Py_asdl_int_seq_new(len, p->arena);
      if (!new_seq) {
          return NULL;
      }
      for (Py_ssize_t i = 0; i < len; i++) {
          CmpopExprPair *pair = asdl_seq_GET_UNTYPED(seq, i);
          asdl_seq_SET(new_seq, i, pair->cmpop);
      }
      return new_seq;
  }
  
  asdl_expr_seq *
  _PyPegen_get_exprs(Parser *p, asdl_seq *seq)
  {
      Py_ssize_t len = asdl_seq_LEN(seq);
      assert(len > 0);
  
      asdl_expr_seq *new_seq = _Py_asdl_expr_seq_new(len, p->arena);
      if (!new_seq) {
          return NULL;
      }
      for (Py_ssize_t i = 0; i < len; i++) {
          CmpopExprPair *pair = asdl_seq_GET_UNTYPED(seq, i);
          asdl_seq_SET(new_seq, i, pair->expr);
      }
      return new_seq;
  }
  
  /* Creates an asdl_seq* where all the elements have been changed to have ctx as context */
  static asdl_expr_seq *
  _set_seq_context(Parser *p, asdl_expr_seq *seq, expr_context_ty ctx)
  {
      Py_ssize_t len = asdl_seq_LEN(seq);
      if (len == 0) {
          return NULL;
      }
  
      asdl_expr_seq *new_seq = _Py_asdl_expr_seq_new(len, p->arena);
      if (!new_seq) {
          return NULL;
      }
      for (Py_ssize_t i = 0; i < len; i++) {
          expr_ty e = asdl_seq_GET(seq, i);
          asdl_seq_SET(new_seq, i, _PyPegen_set_expr_context(p, e, ctx));
      }
      return new_seq;
  }
  
  static expr_ty
  _set_name_context(Parser *p, expr_ty e, expr_context_ty ctx)
  {
      return _PyAST_Name(e->v.Name.id, ctx, EXTRA_EXPR(e, e));
  }
  
  static expr_ty
  _set_tuple_context(Parser *p, expr_ty e, expr_context_ty ctx)
  {
      return _PyAST_Tuple(
              _set_seq_context(p, e->v.Tuple.elts, ctx),
              ctx,
              EXTRA_EXPR(e, e));
  }
  
  static expr_ty
  _set_list_context(Parser *p, expr_ty e, expr_context_ty ctx)
  {
      return _PyAST_List(
              _set_seq_context(p, e->v.List.elts, ctx),
              ctx,
              EXTRA_EXPR(e, e));
  }
  
  static expr_ty
  _set_subscript_context(Parser *p, expr_ty e, expr_context_ty ctx)
  {
      return _PyAST_Subscript(e->v.Subscript.value, e->v.Subscript.slice,
                              ctx, EXTRA_EXPR(e, e));
  }
  
  static expr_ty
  _set_attribute_context(Parser *p, expr_ty e, expr_context_ty ctx)
  {
      return _PyAST_Attribute(e->v.Attribute.value, e->v.Attribute.attr,
                              ctx, EXTRA_EXPR(e, e));
  }
  
  static expr_ty
  _set_starred_context(Parser *p, expr_ty e, expr_context_ty ctx)
  {
      return _PyAST_Starred(_PyPegen_set_expr_context(p, e->v.Starred.value, ctx),
                            ctx, EXTRA_EXPR(e, e));
  }
  
  /* Creates an `expr_ty` equivalent to `expr` but with `ctx` as context */
  expr_ty
  _PyPegen_set_expr_context(Parser *p, expr_ty expr, expr_context_ty ctx)
  {
      assert(expr != NULL);
  
      expr_ty new = NULL;
      switch (expr->kind) {
          case Name_kind:
              new = _set_name_context(p, expr, ctx);
              break;
          case Tuple_kind:
              new = _set_tuple_context(p, expr, ctx);
              break;
          case List_kind:
              new = _set_list_context(p, expr, ctx);
              break;
          case Subscript_kind:
              new = _set_subscript_context(p, expr, ctx);
              break;
          case Attribute_kind:
              new = _set_attribute_context(p, expr, ctx);
              break;
          case Starred_kind:
              new = _set_starred_context(p, expr, ctx);
              break;
          default:
              new = expr;
      }
      return new;
  }
  
  /* Constructs a KeyValuePair that is used when parsing a dict's key value pairs */
  KeyValuePair *
  _PyPegen_key_value_pair(Parser *p, expr_ty key, expr_ty value)
  {
      KeyValuePair *a = _PyArena_Malloc(p->arena, sizeof(KeyValuePair));
      if (!a) {
          return NULL;
      }
      a->key = key;
      a->value = value;
      return a;
  }
  
  /* Extracts all keys from an asdl_seq* of KeyValuePair*'s */
  asdl_expr_seq *
  _PyPegen_get_keys(Parser *p, asdl_seq *seq)
  {
      Py_ssize_t len = asdl_seq_LEN(seq);
      asdl_expr_seq *new_seq = _Py_asdl_expr_seq_new(len, p->arena);
      if (!new_seq) {
          return NULL;
      }
      for (Py_ssize_t i = 0; i < len; i++) {
          KeyValuePair *pair = asdl_seq_GET_UNTYPED(seq, i);
          asdl_seq_SET(new_seq, i, pair->key);
      }
      return new_seq;
  }
  
  /* Extracts all values from an asdl_seq* of KeyValuePair*'s */
  asdl_expr_seq *
  _PyPegen_get_values(Parser *p, asdl_seq *seq)
  {
      Py_ssize_t len = asdl_seq_LEN(seq);
      asdl_expr_seq *new_seq = _Py_asdl_expr_seq_new(len, p->arena);
      if (!new_seq) {
          return NULL;
      }
      for (Py_ssize_t i = 0; i < len; i++) {
          KeyValuePair *pair = asdl_seq_GET_UNTYPED(seq, i);
          asdl_seq_SET(new_seq, i, pair->value);
      }
      return new_seq;
  }
  
  /* Constructs a KeyPatternPair that is used when parsing mapping & class patterns */
  KeyPatternPair *
  _PyPegen_key_pattern_pair(Parser *p, expr_ty key, pattern_ty pattern)
  {
      KeyPatternPair *a = _PyArena_Malloc(p->arena, sizeof(KeyPatternPair));
      if (!a) {
          return NULL;
      }
      a->key = key;
      a->pattern = pattern;
      return a;
  }
  
  /* Extracts all keys from an asdl_seq* of KeyPatternPair*'s */
  asdl_expr_seq *
  _PyPegen_get_pattern_keys(Parser *p, asdl_seq *seq)
  {
      Py_ssize_t len = asdl_seq_LEN(seq);
      asdl_expr_seq *new_seq = _Py_asdl_expr_seq_new(len, p->arena);
      if (!new_seq) {
          return NULL;
      }
      for (Py_ssize_t i = 0; i < len; i++) {
          KeyPatternPair *pair = asdl_seq_GET_UNTYPED(seq, i);
          asdl_seq_SET(new_seq, i, pair->key);
      }
      return new_seq;
  }
  
  /* Extracts all patterns from an asdl_seq* of KeyPatternPair*'s */
  asdl_pattern_seq *
  _PyPegen_get_patterns(Parser *p, asdl_seq *seq)
  {
      Py_ssize_t len = asdl_seq_LEN(seq);
      asdl_pattern_seq *new_seq = _Py_asdl_pattern_seq_new(len, p->arena);
      if (!new_seq) {
          return NULL;
      }
      for (Py_ssize_t i = 0; i < len; i++) {
          KeyPatternPair *pair = asdl_seq_GET_UNTYPED(seq, i);
          asdl_seq_SET(new_seq, i, pair->pattern);
      }
      return new_seq;
  }
  
  /* Constructs a NameDefaultPair */
  NameDefaultPair *
  _PyPegen_name_default_pair(Parser *p, arg_ty arg, expr_ty value, Token *tc)
  {
      NameDefaultPair *a = _PyArena_Malloc(p->arena, sizeof(NameDefaultPair));
      if (!a) {
          return NULL;
      }
      a->arg = _PyPegen_add_type_comment_to_arg(p, arg, tc);
      a->value = value;
      return a;
  }
  
  /* Constructs a SlashWithDefault */
  SlashWithDefault *
  _PyPegen_slash_with_default(Parser *p, asdl_arg_seq *plain_names, asdl_seq *names_with_defaults)
  {
      SlashWithDefault *a = _PyArena_Malloc(p->arena, sizeof(SlashWithDefault));
      if (!a) {
          return NULL;
      }
      a->plain_names = plain_names;
      a->names_with_defaults = names_with_defaults;
      return a;
  }
  
  /* Constructs a StarEtc */
  StarEtc *
  _PyPegen_star_etc(Parser *p, arg_ty vararg, asdl_seq *kwonlyargs, arg_ty kwarg)
  {
      StarEtc *a = _PyArena_Malloc(p->arena, sizeof(StarEtc));
      if (!a) {
          return NULL;
      }
      a->vararg = vararg;
      a->kwonlyargs = kwonlyargs;
      a->kwarg = kwarg;
      return a;
  }
  
  asdl_seq *
  _PyPegen_join_sequences(Parser *p, asdl_seq *a, asdl_seq *b)
  {
      Py_ssize_t first_len = asdl_seq_LEN(a);
      Py_ssize_t second_len = asdl_seq_LEN(b);
      asdl_seq *new_seq = (asdl_seq*)_Py_asdl_generic_seq_new(first_len + second_len, p->arena);
      if (!new_seq) {
          return NULL;
      }
  
      int k = 0;
      for (Py_ssize_t i = 0; i < first_len; i++) {
          asdl_seq_SET_UNTYPED(new_seq, k++, asdl_seq_GET_UNTYPED(a, i));
      }
      for (Py_ssize_t i = 0; i < second_len; i++) {
          asdl_seq_SET_UNTYPED(new_seq, k++, asdl_seq_GET_UNTYPED(b, i));
      }
  
      return new_seq;
  }
  
  static asdl_arg_seq*
  _get_names(Parser *p, asdl_seq *names_with_defaults)
  {
      Py_ssize_t len = asdl_seq_LEN(names_with_defaults);
      asdl_arg_seq *seq = _Py_asdl_arg_seq_new(len, p->arena);
      if (!seq) {
          return NULL;
      }
      for (Py_ssize_t i = 0; i < len; i++) {
          NameDefaultPair *pair = asdl_seq_GET_UNTYPED(names_with_defaults, i);
          asdl_seq_SET(seq, i, pair->arg);
      }
      return seq;
  }
  
  static asdl_expr_seq *
  _get_defaults(Parser *p, asdl_seq *names_with_defaults)
  {
      Py_ssize_t len = asdl_seq_LEN(names_with_defaults);
      asdl_expr_seq *seq = _Py_asdl_expr_seq_new(len, p->arena);
      if (!seq) {
          return NULL;
      }
      for (Py_ssize_t i = 0; i < len; i++) {
          NameDefaultPair *pair = asdl_seq_GET_UNTYPED(names_with_defaults, i);
          asdl_seq_SET(seq, i, pair->value);
      }
      return seq;
  }
  
  static int
  _make_posonlyargs(Parser *p,
                    asdl_arg_seq *slash_without_default,
                    SlashWithDefault *slash_with_default,
                    asdl_arg_seq **posonlyargs) {
      if (slash_without_default != NULL) {
          *posonlyargs = slash_without_default;
      }
      else if (slash_with_default != NULL) {
          asdl_arg_seq *slash_with_default_names =
                  _get_names(p, slash_with_default->names_with_defaults);
          if (!slash_with_default_names) {
              return -1;
          }
          *posonlyargs = (asdl_arg_seq*)_PyPegen_join_sequences(
                  p,
                  (asdl_seq*)slash_with_default->plain_names,
                  (asdl_seq*)slash_with_default_names);
      }
      else {
          *posonlyargs = _Py_asdl_arg_seq_new(0, p->arena);
      }
      return *posonlyargs == NULL ? -1 : 0;
  }
  
  static int
  _make_posargs(Parser *p,
                asdl_arg_seq *plain_names,
                asdl_seq *names_with_default,
                asdl_arg_seq **posargs) {
      if (plain_names != NULL && names_with_default != NULL) {
          asdl_arg_seq *names_with_default_names = _get_names(p, names_with_default);
          if (!names_with_default_names) {
              return -1;
          }
          *posargs = (asdl_arg_seq*)_PyPegen_join_sequences(
                  p,(asdl_seq*)plain_names, (asdl_seq*)names_with_default_names);
      }
      else if (plain_names == NULL && names_with_default != NULL) {
          *posargs = _get_names(p, names_with_default);
      }
      else if (plain_names != NULL && names_with_default == NULL) {
          *posargs = plain_names;
      }
      else {
          *posargs = _Py_asdl_arg_seq_new(0, p->arena);
      }
      return *posargs == NULL ? -1 : 0;
  }
  
  static int
  _make_posdefaults(Parser *p,
                    SlashWithDefault *slash_with_default,
                    asdl_seq *names_with_default,
                    asdl_expr_seq **posdefaults) {
      if (slash_with_default != NULL && names_with_default != NULL) {
          asdl_expr_seq *slash_with_default_values =
                  _get_defaults(p, slash_with_default->names_with_defaults);
          if (!slash_with_default_values) {
              return -1;
          }
          asdl_expr_seq *names_with_default_values = _get_defaults(p, names_with_default);
          if (!names_with_default_values) {
              return -1;
          }
          *posdefaults = (asdl_expr_seq*)_PyPegen_join_sequences(
                  p,
                  (asdl_seq*)slash_with_default_values,
                  (asdl_seq*)names_with_default_values);
      }
      else if (slash_with_default == NULL && names_with_default != NULL) {
          *posdefaults = _get_defaults(p, names_with_default);
      }
      else if (slash_with_default != NULL && names_with_default == NULL) {
          *posdefaults = _get_defaults(p, slash_with_default->names_with_defaults);
      }
      else {
          *posdefaults = _Py_asdl_expr_seq_new(0, p->arena);
      }
      return *posdefaults == NULL ? -1 : 0;
  }
  
  static int
  _make_kwargs(Parser *p, StarEtc *star_etc,
               asdl_arg_seq **kwonlyargs,
               asdl_expr_seq **kwdefaults) {
      if (star_etc != NULL && star_etc->kwonlyargs != NULL) {
          *kwonlyargs = _get_names(p, star_etc->kwonlyargs);
      }
      else {
          *kwonlyargs = _Py_asdl_arg_seq_new(0, p->arena);
      }
  
      if (*kwonlyargs == NULL) {
          return -1;
      }
  
      if (star_etc != NULL && star_etc->kwonlyargs != NULL) {
          *kwdefaults = _get_defaults(p, star_etc->kwonlyargs);
      }
      else {
          *kwdefaults = _Py_asdl_expr_seq_new(0, p->arena);
      }
  
      if (*kwdefaults == NULL) {
          return -1;
      }
  
      return 0;
  }
  
  /* Constructs an arguments_ty object out of all the parsed constructs in the parameters rule */
  arguments_ty
  _PyPegen_make_arguments(Parser *p, asdl_arg_seq *slash_without_default,
                          SlashWithDefault *slash_with_default, asdl_arg_seq *plain_names,
                          asdl_seq *names_with_default, StarEtc *star_etc)
  {
      asdl_arg_seq *posonlyargs;
      if (_make_posonlyargs(p, slash_without_default, slash_with_default, &posonlyargs) == -1) {
          return NULL;
      }
  
      asdl_arg_seq *posargs;
      if (_make_posargs(p, plain_names, names_with_default, &posargs) == -1) {
          return NULL;
      }
  
      asdl_expr_seq *posdefaults;
      if (_make_posdefaults(p,slash_with_default, names_with_default, &posdefaults) == -1) {
          return NULL;
      }
  
      arg_ty vararg = NULL;
      if (star_etc != NULL && star_etc->vararg != NULL) {
          vararg = star_etc->vararg;
      }
  
      asdl_arg_seq *kwonlyargs;
      asdl_expr_seq *kwdefaults;
      if (_make_kwargs(p, star_etc, &kwonlyargs, &kwdefaults) == -1) {
          return NULL;
      }
  
      arg_ty kwarg = NULL;
      if (star_etc != NULL && star_etc->kwarg != NULL) {
          kwarg = star_etc->kwarg;
      }
  
      return _PyAST_arguments(posonlyargs, posargs, vararg, kwonlyargs,
                              kwdefaults, kwarg, posdefaults, p->arena);
  }
  
  
  /* Constructs an empty arguments_ty object, that gets used when a function accepts no
   * arguments. */
  arguments_ty
  _PyPegen_empty_arguments(Parser *p)
  {
      asdl_arg_seq *posonlyargs = _Py_asdl_arg_seq_new(0, p->arena);
      if (!posonlyargs) {
          return NULL;
      }
      asdl_arg_seq *posargs = _Py_asdl_arg_seq_new(0, p->arena);
      if (!posargs) {
          return NULL;
      }
      asdl_expr_seq *posdefaults = _Py_asdl_expr_seq_new(0, p->arena);
      if (!posdefaults) {
          return NULL;
      }
      asdl_arg_seq *kwonlyargs = _Py_asdl_arg_seq_new(0, p->arena);
      if (!kwonlyargs) {
          return NULL;
      }
      asdl_expr_seq *kwdefaults = _Py_asdl_expr_seq_new(0, p->arena);
      if (!kwdefaults) {
          return NULL;
      }
  
      return _PyAST_arguments(posonlyargs, posargs, NULL, kwonlyargs,
                              kwdefaults, NULL, posdefaults, p->arena);
  }
  
  /* Encapsulates the value of an operator_ty into an AugOperator struct */
  AugOperator *
  _PyPegen_augoperator(Parser *p, operator_ty kind)
  {
      AugOperator *a = _PyArena_Malloc(p->arena, sizeof(AugOperator));
      if (!a) {
          return NULL;
      }
      a->kind = kind;
      return a;
  }
  
  /* Construct a FunctionDef equivalent to function_def, but with decorators */
  stmt_ty
  _PyPegen_function_def_decorators(Parser *p, asdl_expr_seq *decorators, stmt_ty function_def)
  {
      assert(function_def != NULL);
      if (function_def->kind == AsyncFunctionDef_kind) {
          return _PyAST_AsyncFunctionDef(
              function_def->v.FunctionDef.name, function_def->v.FunctionDef.args,
              function_def->v.FunctionDef.body, decorators, function_def->v.FunctionDef.returns,
              function_def->v.FunctionDef.type_comment, function_def->lineno,
              function_def->col_offset, function_def->end_lineno, function_def->end_col_offset,
              p->arena);
      }
  
      return _PyAST_FunctionDef(
          function_def->v.FunctionDef.name, function_def->v.FunctionDef.args,
          function_def->v.FunctionDef.body, decorators,
          function_def->v.FunctionDef.returns,
          function_def->v.FunctionDef.type_comment, function_def->lineno,
          function_def->col_offset, function_def->end_lineno,
          function_def->end_col_offset, p->arena);
  }
  
  /* Construct a ClassDef equivalent to class_def, but with decorators */
  stmt_ty
  _PyPegen_class_def_decorators(Parser *p, asdl_expr_seq *decorators, stmt_ty class_def)
  {
      assert(class_def != NULL);
      return _PyAST_ClassDef(
          class_def->v.ClassDef.name, class_def->v.ClassDef.bases,
          class_def->v.ClassDef.keywords, class_def->v.ClassDef.body, decorators,
          class_def->lineno, class_def->col_offset, class_def->end_lineno,
          class_def->end_col_offset, p->arena);
  }
  
  /* Construct a KeywordOrStarred */
  KeywordOrStarred *
  _PyPegen_keyword_or_starred(Parser *p, void *element, int is_keyword)
  {
      KeywordOrStarred *a = _PyArena_Malloc(p->arena, sizeof(KeywordOrStarred));
      if (!a) {
          return NULL;
      }
      a->element = element;
      a->is_keyword = is_keyword;
      return a;
  }
  
  /* Get the number of starred expressions in an asdl_seq* of KeywordOrStarred*s */
  static int
  _seq_number_of_starred_exprs(asdl_seq *seq)
  {
      int n = 0;
      for (Py_ssize_t i = 0, l = asdl_seq_LEN(seq); i < l; i++) {
          KeywordOrStarred *k = asdl_seq_GET_UNTYPED(seq, i);
          if (!k->is_keyword) {
              n++;
          }
      }
      return n;
  }
  
  /* Extract the starred expressions of an asdl_seq* of KeywordOrStarred*s */
  asdl_expr_seq *
  _PyPegen_seq_extract_starred_exprs(Parser *p, asdl_seq *kwargs)
  {
      int new_len = _seq_number_of_starred_exprs(kwargs);
      if (new_len == 0) {
          return NULL;
      }
      asdl_expr_seq *new_seq = _Py_asdl_expr_seq_new(new_len, p->arena);
      if (!new_seq) {
          return NULL;
      }
  
      int idx = 0;
      for (Py_ssize_t i = 0, len = asdl_seq_LEN(kwargs); i < len; i++) {
          KeywordOrStarred *k = asdl_seq_GET_UNTYPED(kwargs, i);
          if (!k->is_keyword) {
              asdl_seq_SET(new_seq, idx++, k->element);
          }
      }
      return new_seq;
  }
  
  /* Return a new asdl_seq* with only the keywords in kwargs */
  asdl_keyword_seq*
  _PyPegen_seq_delete_starred_exprs(Parser *p, asdl_seq *kwargs)
  {
      Py_ssize_t len = asdl_seq_LEN(kwargs);
      Py_ssize_t new_len = len - _seq_number_of_starred_exprs(kwargs);
      if (new_len == 0) {
          return NULL;
      }
      asdl_keyword_seq *new_seq = _Py_asdl_keyword_seq_new(new_len, p->arena);
      if (!new_seq) {
          return NULL;
      }
  
      int idx = 0;
      for (Py_ssize_t i = 0; i < len; i++) {
          KeywordOrStarred *k = asdl_seq_GET_UNTYPED(kwargs, i);
          if (k->is_keyword) {
              asdl_seq_SET(new_seq, idx++, k->element);
          }
      }
      return new_seq;
  }
  
  expr_ty
  _PyPegen_concatenate_strings(Parser *p, asdl_seq *strings)
  {
      Py_ssize_t len = asdl_seq_LEN(strings);
      assert(len > 0);
  
      Token *first = asdl_seq_GET_UNTYPED(strings, 0);
      Token *last = asdl_seq_GET_UNTYPED(strings, len - 1);
  
      int bytesmode = 0;
      PyObject *bytes_str = NULL;
  
      FstringParser state;
      _PyPegen_FstringParser_Init(&state);
  
      for (Py_ssize_t i = 0; i < len; i++) {
          Token *t = asdl_seq_GET_UNTYPED(strings, i);
  
          int this_bytesmode;
          int this_rawmode;
          PyObject *s;
          const char *fstr;
          Py_ssize_t fstrlen = -1;
  
          if (_PyPegen_parsestr(p, &this_bytesmode, &this_rawmode, &s, &fstr, &fstrlen, t) != 0) {
              goto error;
          }
  
          /* Check that we are not mixing bytes with unicode. */
          if (i != 0 && bytesmode != this_bytesmode) {
              RAISE_SYNTAX_ERROR("cannot mix bytes and nonbytes literals");
              Py_XDECREF(s);
              goto error;
          }
          bytesmode = this_bytesmode;
  
          if (fstr != NULL) {
              assert(s == NULL && !bytesmode);
  
              int result = _PyPegen_FstringParser_ConcatFstring(p, &state, &fstr, fstr + fstrlen,
                                                       this_rawmode, 0, first, t, last);
              if (result < 0) {
                  goto error;
              }
          }
          else {
              /* String or byte string. */
              assert(s != NULL && fstr == NULL);
              assert(bytesmode ? PyBytes_CheckExact(s) : PyUnicode_CheckExact(s));
  
              if (bytesmode) {
                  if (i == 0) {
                      bytes_str = s;
                  }
                  else {
                      PyBytes_ConcatAndDel(&bytes_str, s);
                      if (!bytes_str) {
                          goto error;
                      }
                  }
              }
              else {
                  /* This is a regular string. Concatenate it. */
                  if (_PyPegen_FstringParser_ConcatAndDel(&state, s) < 0) {
                      goto error;
                  }
              }
          }
      }
  
      if (bytesmode) {
          if (_PyArena_AddPyObject(p->arena, bytes_str) < 0) {
              goto error;
          }
          return _PyAST_Constant(bytes_str, NULL, first->lineno,
                                 first->col_offset, last->end_lineno,
                                 last->end_col_offset, p->arena);
      }
  
      return _PyPegen_FstringParser_Finish(p, &state, first, last);
  
  error:
      Py_XDECREF(bytes_str);
      _PyPegen_FstringParser_Dealloc(&state);
      if (PyErr_Occurred()) {
          _Pypegen_raise_decode_error(p);
      }
      return NULL;
  }
  
  expr_ty
  _PyPegen_ensure_imaginary(Parser *p, expr_ty exp)
  {
      if (exp->kind != Constant_kind || !PyComplex_CheckExact(exp->v.Constant.value)) {
          RAISE_SYNTAX_ERROR_KNOWN_LOCATION(exp, "imaginary number required in complex literal");
          return NULL;
      }
      return exp;
  }
  
  expr_ty
  _PyPegen_ensure_real(Parser *p, expr_ty exp)
  {
      if (exp->kind != Constant_kind || PyComplex_CheckExact(exp->v.Constant.value)) {
          RAISE_SYNTAX_ERROR_KNOWN_LOCATION(exp, "real number required in complex literal");
          return NULL;
      }
      return exp;
  }
  
  mod_ty
  _PyPegen_make_module(Parser *p, asdl_stmt_seq *a) {
      asdl_type_ignore_seq *type_ignores = NULL;
      Py_ssize_t num = p->type_ignore_comments.num_items;
      if (num > 0) {
          // Turn the raw (comment, lineno) pairs into TypeIgnore objects in the arena
          type_ignores = _Py_asdl_type_ignore_seq_new(num, p->arena);
          if (type_ignores == NULL) {
              return NULL;
          }
          for (int i = 0; i < num; i++) {
              PyObject *tag = _PyPegen_new_type_comment(p, p->type_ignore_comments.items[i].comment);
              if (tag == NULL) {
                  return NULL;
              }
              type_ignore_ty ti = _PyAST_TypeIgnore(p->type_ignore_comments.items[i].lineno,
                                                    tag, p->arena);
              if (ti == NULL) {
                  return NULL;
              }
              asdl_seq_SET(type_ignores, i, ti);
          }
      }
      return _PyAST_Module(a, type_ignores, p->arena);
  }
  
  PyObject *
  _PyPegen_new_type_comment(Parser *p, const char *s)
  {
      PyObject *res = PyUnicode_DecodeUTF8(s, strlen(s), NULL);
      if (res == NULL) {
          return NULL;
      }
      if (_PyArena_AddPyObject(p->arena, res) < 0) {
          Py_DECREF(res);
          return NULL;
      }
      return res;
  }
  
  arg_ty
  _PyPegen_add_type_comment_to_arg(Parser *p, arg_ty a, Token *tc)
  {
      if (tc == NULL) {
          return a;
      }
      const char *bytes = PyBytes_AsString(tc->bytes);
      if (bytes == NULL) {
          return NULL;
      }
      PyObject *tco = _PyPegen_new_type_comment(p, bytes);
      if (tco == NULL) {
          return NULL;
      }
      return _PyAST_arg(a->arg, a->annotation, tco,
                        a->lineno, a->col_offset, a->end_lineno, a->end_col_offset,
                        p->arena);
  }
  
  /* Checks if the NOTEQUAL token is valid given the current parser flags
  0 indicates success and nonzero indicates failure (an exception may be set) */
  int
  _PyPegen_check_barry_as_flufl(Parser *p, Token* t) {
      assert(t->bytes != NULL);
      assert(t->type == NOTEQUAL);
  
      const char* tok_str = PyBytes_AS_STRING(t->bytes);
      if (p->flags & PyPARSE_BARRY_AS_BDFL && strcmp(tok_str, "<>") != 0) {
          RAISE_SYNTAX_ERROR("with Barry as BDFL, use '<>' instead of '!='");
          return -1;
      }
      if (!(p->flags & PyPARSE_BARRY_AS_BDFL)) {
          return strcmp(tok_str, "!=");
      }
      return 0;
  }
  
  int
  _PyPegen_check_legacy_stmt(Parser *p, expr_ty name) {
      if (name->kind != Name_kind) {
          return 0;
      }
      const char* candidates[2] = {"print", "exec"};
      for (int i=0; i<2; i++) {
          if (PyUnicode_CompareWithASCIIString(name->v.Name.id, candidates[i]) == 0) {
              return 1;
          }
      }
      return 0;
  }
  
  const char *
  _PyPegen_get_expr_name(expr_ty e)
  {
      assert(e != NULL);
      switch (e->kind) {
          case Attribute_kind:
              return "attribute";
          case Subscript_kind:
              return "subscript";
          case Starred_kind:
              return "starred";
          case Name_kind:
              return "name";
          case List_kind:
              return "list";
          case Tuple_kind:
              return "tuple";
          case Lambda_kind:
              return "lambda";
          case Call_kind:
              return "function call";
          case BoolOp_kind:
          case BinOp_kind:
          case UnaryOp_kind:
              return "expression";
          case GeneratorExp_kind:
              return "generator expression";
          case Yield_kind:
          case YieldFrom_kind:
              return "yield expression";
          case Await_kind:
              return "await expression";
          case ListComp_kind:
              return "list comprehension";
          case SetComp_kind:
              return "set comprehension";
          case DictComp_kind:
              return "dict comprehension";
          case Dict_kind:
              return "dict literal";
          case Set_kind:
              return "set display";
          case JoinedStr_kind:
          case FormattedValue_kind:
              return "f-string expression";
          case Constant_kind: {
              PyObject *value = e->v.Constant.value;
              if (value == Py_None) {
                  return "None";
              }
              if (value == Py_False) {
                  return "False";
              }
              if (value == Py_True) {
                  return "True";
              }
              if (value == Py_Ellipsis) {
                  return "ellipsis";
              }
              return "literal";
          }
          case Compare_kind:
              return "comparison";
          case IfExp_kind:
              return "conditional expression";
          case NamedExpr_kind:
              return "named expression";
          default:
              PyErr_Format(PyExc_SystemError,
                           "unexpected expression in assignment %d (line %d)",
                           e->kind, e->lineno);
              return NULL;
      }
  }
  
  expr_ty
  _PyPegen_get_last_comprehension_item(comprehension_ty comprehension) {
      if (comprehension->ifs == NULL || asdl_seq_LEN(comprehension->ifs) == 0) {
          return comprehension->iter;
      }
      return PyPegen_last_item(comprehension->ifs, expr_ty);
  }
  
  expr_ty _PyPegen_collect_call_seqs(Parser *p, asdl_expr_seq *a, asdl_seq *b,
                       int lineno, int col_offset, int end_lineno,
                       int end_col_offset, PyArena *arena) {
      Py_ssize_t args_len = asdl_seq_LEN(a);
      Py_ssize_t total_len = args_len;
  
      if (b == NULL) {
          return _PyAST_Call(_PyPegen_dummy_name(p), a, NULL, lineno, col_offset,
                          end_lineno, end_col_offset, arena);
  
      }
  
      asdl_expr_seq *starreds = _PyPegen_seq_extract_starred_exprs(p, b);
      asdl_keyword_seq *keywords = _PyPegen_seq_delete_starred_exprs(p, b);
  
      if (starreds) {
          total_len += asdl_seq_LEN(starreds);
      }
  
      asdl_expr_seq *args = _Py_asdl_expr_seq_new(total_len, arena);
  
      Py_ssize_t i = 0;
      for (i = 0; i < args_len; i++) {
          asdl_seq_SET(args, i, asdl_seq_GET(a, i));
      }
      for (; i < total_len; i++) {
          asdl_seq_SET(args, i, asdl_seq_GET(starreds, i - args_len));
      }
  
      return _PyAST_Call(_PyPegen_dummy_name(p), args, keywords, lineno,
                         col_offset, end_lineno, end_col_offset, arena);
  }
  
  // AST Error reporting helpers
  
  expr_ty
  _PyPegen_get_invalid_target(expr_ty e, TARGETS_TYPE targets_type)
  {
      if (e == NULL) {
          return NULL;
      }
  
  #define VISIT_CONTAINER(CONTAINER, TYPE) do { \
          Py_ssize_t len = asdl_seq_LEN((CONTAINER)->v.TYPE.elts);\
          for (Py_ssize_t i = 0; i < len; i++) {\
              expr_ty other = asdl_seq_GET((CONTAINER)->v.TYPE.elts, i);\
              expr_ty child = _PyPegen_get_invalid_target(other, targets_type);\
              if (child != NULL) {\
                  return child;\
              }\
          }\
      } while (0)
  
      // We only need to visit List and Tuple nodes recursively as those
      // are the only ones that can contain valid names in targets when
      // they are parsed as expressions. Any other kind of expression
      // that is a container (like Sets or Dicts) is directly invalid and
      // we don't need to visit it recursively.
  
      switch (e->kind) {
          case List_kind:
              VISIT_CONTAINER(e, List);
              return NULL;
          case Tuple_kind:
              VISIT_CONTAINER(e, Tuple);
              return NULL;
          case Starred_kind:
              if (targets_type == DEL_TARGETS) {
                  return e;
              }
              return _PyPegen_get_invalid_target(e->v.Starred.value, targets_type);
          case Compare_kind:
              // This is needed, because the `a in b` in `for a in b` gets parsed
              // as a comparison, and so we need to search the left side of the comparison
              // for invalid targets.
              if (targets_type == FOR_TARGETS) {
                  cmpop_ty cmpop = (cmpop_ty) asdl_seq_GET(e->v.Compare.ops, 0);
                  if (cmpop == In) {
                      return _PyPegen_get_invalid_target(e->v.Compare.left, targets_type);
                  }
                  return NULL;
              }
              return e;
          case Name_kind:
          case Subscript_kind:
          case Attribute_kind:
              return NULL;
          default:
              return e;
      }
  }
  
  void *_PyPegen_arguments_parsing_error(Parser *p, expr_ty e) {
      int kwarg_unpacking = 0;
      for (Py_ssize_t i = 0, l = asdl_seq_LEN(e->v.Call.keywords); i < l; i++) {
          keyword_ty keyword = asdl_seq_GET(e->v.Call.keywords, i);
          if (!keyword->arg) {
              kwarg_unpacking = 1;
          }
      }
  
      const char *msg = NULL;
      if (kwarg_unpacking) {
          msg = "positional argument follows keyword argument unpacking";
      } else {
          msg = "positional argument follows keyword argument";
      }
  
      return RAISE_SYNTAX_ERROR(msg);
  }
  
  void *
  _PyPegen_nonparen_genexp_in_call(Parser *p, expr_ty args, asdl_comprehension_seq *comprehensions)
  {
      /* The rule that calls this function is 'args for_if_clauses'.
         For the input f(L, x for x in y), L and x are in args and
         the for is parsed as a for_if_clause. We have to check if
         len <= 1, so that input like dict((a, b) for a, b in x)
         gets successfully parsed and then we pass the last
         argument (x in the above example) as the location of the
         error */
      Py_ssize_t len = asdl_seq_LEN(args->v.Call.args);
      if (len <= 1) {
          return NULL;
      }
  
      comprehension_ty last_comprehension = PyPegen_last_item(comprehensions, comprehension_ty);
  
      return RAISE_SYNTAX_ERROR_KNOWN_RANGE(
          (expr_ty) asdl_seq_GET(args->v.Call.args, len - 1),
          _PyPegen_get_last_comprehension_item(last_comprehension),
          "Generator expression must be parenthesized"
      );
  }