text: 
  #include <stdio.h>   /* printf etc */
  #include <stdlib.h>  /* exit */
  #include <string.h>  /* memmove */
  #include "header.h"
  
  typedef enum {
      e_token_omitted = 0,
      e_unexpected_token = 1,
      e_string_omitted = 2,
      e_unexpected_token_in_among = 3,
      // For codes above here, report "after " t->previous_token after the error.
      e_unresolved_substring = 14,
      e_not_allowed_inside_reverse = 15,
      e_empty_grouping = 16,
      e_already_backwards = 17,
      e_empty_among = 18,
      e_adjacent_bracketed_in_among = 19,
      e_substring_preceded_by_substring = 20,
      // For codes below here, tokeniser->b is printed before the error.
      e_redeclared = 30,
      e_undeclared = 31,
      e_declared_as_different_mode = 32,
      e_not_of_type_x = 33,
      e_not_of_type_string_or_integer = 34,
      e_misplaced = 35,
      e_redefined = 36,
      e_misused = 37
  } error_code;
  
  /* recursive usage: */
  
  static void read_program_(struct analyser * a, int terminator);
  static struct node * read_C(struct analyser * a);
  static struct node * C_style(struct analyser * a, const char * s, int token);
  
  
  static void fault(int n) { fprintf(stderr, "fault %d\n", n); exit(1); }
  
  static void print_node_(struct node * p, int n, const char * s) {
  
      int i;
      for (i = 0; i < n; i++) fputs(i == n - 1 ? s : "  ", stdout);
      printf("%s ", name_of_token(p->type));
      if (p->name) report_b(stdout, p->name->b);
      if (p->literalstring) {
          printf("'");
          report_b(stdout, p->literalstring);
          printf("'");
      }
      printf("\n");
      if (p->AE) print_node_(p->AE, n+1, "# ");
      if (p->left) print_node_(p->left, n+1, "  ");
      if (p->right) print_node_(p->right, n, "  ");
      if (p->aux) print_node_(p->aux, n+1, "@ ");
  }
  
  extern void print_program(struct analyser * a) {
      print_node_(a->program, 0, "  ");
  }
  
  static struct node * new_node(struct analyser * a, int type) {
      NEW(node, p);
      p->next = a->nodes; a->nodes = p;
      p->left = 0;
      p->right = 0;
      p->aux = 0;
      p->AE = 0;
      p->name = 0;
      p->literalstring = 0;
      p->mode = a->mode;
      p->line_number = a->tokeniser->line_number;
      p->type = type;
      return p;
  }
  
  static const char * name_of_mode(int n) {
      switch (n) {
           default: fault(0);
           case m_backward: return "string backward";
           case m_forward:  return "string forward";
      /*   case m_integer:  return "integer";  */
      }
  }
  
  static const char * name_of_type(int n) {
      switch (n) {
           default: fault(1);
           case 's': return "string";
           case 'i': return "integer";
           case 'r': return "routine";
           case 'R': return "routine or grouping";
           case 'g': return "grouping";
      }
  }
  
  static void count_error(struct analyser * a) {
      struct tokeniser * t = a->tokeniser;
      if (t->error_count >= 20) { fprintf(stderr, "... etc\n"); exit(1); }
      t->error_count++;
  }
  
  static void error2(struct analyser * a, error_code n, int x) {
      struct tokeniser * t = a->tokeniser;
      count_error(a);
      fprintf(stderr, "%s:%d: ", t->file, t->line_number);
      if ((int)n >= (int)e_redeclared) report_b(stderr, t->b);
      switch (n) {
          case e_token_omitted:
              fprintf(stderr, "%s omitted", name_of_token(t->omission)); break;
          case e_unexpected_token_in_among:
              fprintf(stderr, "in among(...), ");
          case e_unexpected_token:
              fprintf(stderr, "unexpected %s", name_of_token(t->token));
              if (t->token == c_number) fprintf(stderr, " %d", t->number);
              if (t->token == c_name) {
                  fprintf(stderr, " ");
                  report_b(stderr, t->b);
              } break;
          case e_string_omitted:
              fprintf(stderr, "string omitted"); break;
  
          case e_unresolved_substring:
              fprintf(stderr, "unresolved substring on line %d", x); break;
          case e_not_allowed_inside_reverse:
              fprintf(stderr, "%s not allowed inside reverse(...)", name_of_token(t->token)); break;
          case e_empty_grouping:
              fprintf(stderr, "empty grouping"); break;
          case e_already_backwards:
              fprintf(stderr, "backwards used when already in this mode"); break;
          case e_empty_among:
              fprintf(stderr, "empty among(...)"); break;
          case e_adjacent_bracketed_in_among:
              fprintf(stderr, "two adjacent bracketed expressions in among(...)"); break;
          case e_substring_preceded_by_substring:
              fprintf(stderr, "substring preceded by another substring on line %d", x); break;
  
          case e_redeclared:
              fprintf(stderr, " re-declared"); break;
          case e_undeclared:
              fprintf(stderr, " undeclared"); break;
          case e_declared_as_different_mode:
              fprintf(stderr, " declared as %s mode; used as %s mode",
                              name_of_mode(a->mode), name_of_mode(x)); break;
          case e_not_of_type_x:
              fprintf(stderr, " not of type %s", name_of_type(x)); break;
          case e_not_of_type_string_or_integer:
              fprintf(stderr, " not of type string or integer"); break;
          case e_misplaced:
              fprintf(stderr, " misplaced"); break;
          case e_redefined:
              fprintf(stderr, " redefined"); break;
          case e_misused:
              fprintf(stderr, " mis-used as %s mode",
                              name_of_mode(x)); break;
      }
      if ((int)n < (int)e_unresolved_substring && t->previous_token > 0)
          fprintf(stderr, " after %s", name_of_token(t->previous_token));
      fprintf(stderr, "\n");
  }
  
  static void error(struct analyser * a, error_code n) { error2(a, n, 0); }
  
  static void error3(struct analyser * a, struct node * p, symbol * b) {
      count_error(a);
      fprintf(stderr, "%s:%d: among(...) has repeated string '", a->tokeniser->file, p->line_number);
      report_b(stderr, b);
      fprintf(stderr, "'\n");
  }
  
  static void error3a(struct analyser * a, struct node * p) {
      count_error(a);
      fprintf(stderr, "%s:%d: previously seen here\n", a->tokeniser->file, p->line_number);
  }
  
  static void error4(struct analyser * a, struct name * q) {
      count_error(a);
      fprintf(stderr, "%s:%d: ", a->tokeniser->file, q->used->line_number);
      report_b(stderr, q->b);
      fprintf(stderr, " undefined\n");
  }
  
  static void omission_error(struct analyser * a, int n) {
      a->tokeniser->omission = n;
      error(a, e_token_omitted);
  }
  
  static int check_token(struct analyser * a, int code) {
      struct tokeniser * t = a->tokeniser;
      if (t->token != code) { omission_error(a, code); return false; }
      return true;
  }
  
  static int get_token(struct analyser * a, int code) {
      struct tokeniser * t = a->tokeniser;
      read_token(t);
      {
          int x = check_token(a, code);
          if (!x) t->token_held = true;
          return x;
      }
  }
  
  static struct name * look_for_name(struct analyser * a) {
      symbol * q = a->tokeniser->b;
      struct name * p;
      for (p = a->names; p; p = p->next) {
          symbol * b = p->b;
          int n = SIZE(b);
          if (n == SIZE(q) && memcmp(q, b, n * sizeof(symbol)) == 0) {
              p->referenced = true;
              return p;
          }
      }
      return 0;
  }
  
  static struct name * find_name(struct analyser * a) {
      struct name * p = look_for_name(a);
      if (p == 0) error(a, e_undeclared);
      return p;
  }
  
  static void check_routine_mode(struct analyser * a, struct name * p, int mode) {
      if (p->mode < 0) p->mode = mode; else
      if (p->mode != mode) error2(a, e_misused, mode);
  }
  
  static void check_name_type(struct analyser * a, struct name * p, int type) {
      switch (type) {
          case 's': if (p->type == t_string) return; break;
          case 'i': if (p->type == t_integer) return; break;
          case 'b': if (p->type == t_boolean) return; break;
          case 'R': if (p->type == t_grouping) return;
          case 'r': if (p->type == t_routine ||
                        p->type == t_external) return; break;
          case 'g': if (p->type == t_grouping) return; break;
      }
      error2(a, e_not_of_type_x, type);
  }
  
  static void read_names(struct analyser * a, int type) {
      struct tokeniser * t = a->tokeniser;
      if (!get_token(a, c_bra)) return;
      while (true) {
          int token = read_token(t);
          switch (token) {
              case c_len: {
                  /* Context-sensitive token - once declared as a name, it loses
                   * its special meaning, for compatibility with older versions
                   * of snowball.
                   */
                  static const symbol c_len_lit[] = {
                      'l', 'e', 'n'
                  };
                  MOVE_TO_B(t->b, c_len_lit);
                  goto handle_as_name;
              }
              case c_lenof: {
                  /* Context-sensitive token - once declared as a name, it loses
                   * its special meaning, for compatibility with older versions
                   * of snowball.
                   */
                  static const symbol c_lenof_lit[] = {
                      'l', 'e', 'n', 'o', 'f'
                  };
                  MOVE_TO_B(t->b, c_lenof_lit);
                  goto handle_as_name;
              }
              case c_name:
  handle_as_name:
                  if (look_for_name(a) != 0) error(a, e_redeclared); else {
                      NEW(name, p);
                      p->b = copy_b(t->b);
                      p->type = type;
                      p->mode = -1; /* routines, externals */
                      p->count = a->name_count[type];
                      p->referenced = false;
                      p->used_in_among = false;
                      p->used = 0;
                      p->local_to = 0;
                      p->grouping = 0;
                      p->definition = 0;
                      a->name_count[type] ++;
                      p->next = a->names;
                      a->names = p;
                      if (token != c_name) {
                          disable_token(t, token);
                      }
                  }
                  break;
              default:
                  if (!check_token(a, c_ket)) t->token_held = true;
                  return;
          }
      }
  }
  
  static symbol * new_literalstring(struct analyser * a) {
      NEW(literalstring, p);
      p->b = copy_b(a->tokeniser->b);
      p->next = a->literalstrings;
      a->literalstrings = p;
      return p->b;
  }
  
  static int read_AE_test(struct analyser * a) {
  
      struct tokeniser * t = a->tokeniser;
      switch (read_token(t)) {
          case c_assign: return c_mathassign;
          case c_plusassign:
          case c_minusassign:
          case c_multiplyassign:
          case c_divideassign:
          case c_eq:
          case c_ne:
          case c_gr:
          case c_ge:
          case c_ls:
          case c_le: return t->token;
          default: error(a, e_unexpected_token); t->token_held = true; return c_eq;
      }
  }
  
  static int binding(int t) {
      switch (t) {
          case c_plus: case c_minus: return 1;
          case c_multiply: case c_divide: return 2;
          default: return -2;
      }
  }
  
  static void mark_used_in(struct analyser * a, struct name * q, struct node * p) {
      if (!q->used) {
          q->used = p;
          q->local_to = a->program_end->name;
      } else if (q->local_to) {
          if (q->local_to != a->program_end->name) {
              /* Used in more than one routine/external. */
              q->local_to = NULL;
          }
      }
  }
  
  static void name_to_node(struct analyser * a, struct node * p, int type) {
      struct name * q = find_name(a);
      if (q) {
          check_name_type(a, q, type);
          mark_used_in(a, q, p);
      }
      p->name = q;
  }
  
  static struct node * read_AE(struct analyser * a, int B) {
      struct tokeniser * t = a->tokeniser;
      struct node * p;
      struct node * q;
      switch (read_token(t)) {
          case c_minus: /* monadic */
              p = new_node(a, c_neg);
              p->right = read_AE(a, 100);
              break;
          case c_bra:
              p = read_AE(a, 0);
              get_token(a, c_ket);
              break;
          case c_name:
              p = new_node(a, c_name);
              name_to_node(a, p, 'i');
              break;
          case c_maxint:
          case c_minint:
              a->int_limits_used = true;
          case c_cursor:
          case c_limit:
          case c_len:
          case c_size:
              p = new_node(a, t->token);
              break;
          case c_number:
              p = new_node(a, c_number);
              p->number = t->number;
              break;
          case c_lenof:
          case c_sizeof:
              p = C_style(a, "s", t->token);
              break;
          default:
              error(a, e_unexpected_token);
              t->token_held = true;
              return 0;
      }
      while (true) {
          int token = read_token(t);
          int b = binding(token);
          if (binding(token) <= B) {
              t->token_held = true;
              return p;
          }
          q = new_node(a, token);
          q->left = p;
          q->right = read_AE(a, b);
          p = q;
      }
  }
  
  static struct node * read_C_connection(struct analyser * a, struct node * q, int op) {
      struct tokeniser * t = a->tokeniser;
      struct node * p = new_node(a, op);
      struct node * p_end = q;
      p->left = q;
      do {
          q = read_C(a);
          p_end->right = q; p_end = q;
      } while (read_token(t) == op);
      t->token_held = true;
      return p;
  }
  
  static struct node * read_C_list(struct analyser * a) {
      struct tokeniser * t = a->tokeniser;
      struct node * p = new_node(a, c_bra);
      struct node * p_end = 0;
      while (true) {
          int token = read_token(t);
          if (token == c_ket) return p;
          if (token < 0) { omission_error(a, c_ket); return p; }
          t->token_held = true;
          {
              struct node * q = read_C(a);
              while (true) {
                  token = read_token(t);
                  if (token != c_and && token != c_or) {
                      t->token_held = true;
                      break;
                  }
                  q = read_C_connection(a, q, token);
              }
              if (p_end == 0) p->left = q; else p_end->right = q;
              p_end = q;
          }
      }
  }
  
  static struct node * C_style(struct analyser * a, const char * s, int token) {
      int i;
      struct node * p = new_node(a, token);
      for (i = 0; s[i] != 0; i++) switch (s[i]) {
          case 'C':
              p->left = read_C(a); continue;
          case 'D':
              p->aux = read_C(a); continue;
          case 'A':
              p->AE = read_AE(a, 0); continue;
          case 'f':
              get_token(a, c_for); continue;
          case 'S':
              {
                  int str_token = read_token(a->tokeniser);
                  if (str_token == c_name) name_to_node(a, p, 's'); else
                  if (str_token == c_literalstring) p->literalstring = new_literalstring(a);
                  else error(a, e_string_omitted);
              }
              continue;
          case 'b':
          case 's':
          case 'i':
              if (get_token(a, c_name)) name_to_node(a, p, s[i]);
              continue;
      }
      return p;
  }
  
  static struct node * read_literalstring(struct analyser * a) {
      struct node * p = new_node(a, c_literalstring);
      p->literalstring = new_literalstring(a);
      return p;
  }
  
  static void reverse_b(symbol * b) {
      int i = 0; int j = SIZE(b) - 1;
      while (i < j) {
          int ch1 = b[i]; int ch2 = b[j];
          b[i++] = ch2; b[j--] = ch1;
      }
  }
  
  static int compare_amongvec(const void *pv, const void *qv) {
      const struct amongvec * p = (const struct amongvec*)pv;
      const struct amongvec * q = (const struct amongvec*)qv;
      symbol * b_p = p->b; int p_size = p->size;
      symbol * b_q = q->b; int q_size = q->size;
      int smaller_size = p_size < q_size ? p_size : q_size;
      int i;
      for (i = 0; i < smaller_size; i++)
          if (b_p[i] != b_q[i]) return b_p[i] - b_q[i];
      if (p_size - q_size)
  	return p_size - q_size;
      return p->p->line_number - q->p->line_number;
  }
  
  static void make_among(struct analyser * a, struct node * p, struct node * substring) {
  
      NEW(among, x);
      NEWVEC(amongvec, v, p->number);
      struct node * q = p->left;
      struct amongvec * w0 = v;
      struct amongvec * w1 = v;
      int result = 1;
  
      int direction = substring != 0 ? substring->mode : p->mode;
      int backward = direction == m_backward;
  
      if (a->amongs == 0) a->amongs = x; else a->amongs_end->next = x;
      a->amongs_end = x;
      x->next = 0;
      x->b = v;
      x->number = a->among_count++;
      x->function_count = 0;
      x->starter = 0;
  
      if (q->type == c_bra) { x->starter = q; q = q->right; }
  
      while (q) {
          if (q->type == c_literalstring) {
              symbol * b = q->literalstring;
              w1->b = b;           /* pointer to case string */
              w1->p = q;           /* pointer to corresponding node */
              w1->size = SIZE(b);  /* number of characters in string */
              w1->i = -1;          /* index of longest substring */
              w1->result = -1;     /* number of corresponding case expression */
              if (q->left) {
                  struct name * function = q->left->name;
                  w1->function = function;
                  function->used_in_among = true;
                  check_routine_mode(a, function, direction);
                  x->function_count++;
              } else {
                  w1->function = 0;
              }
              w1++;
          }
          else
          if (q->left == 0)  /* empty command: () */
              w0 = w1;
          else {
              while (w0 != w1) {
                  w0->p = q;
                  w0->result = result;
                  w0++;
              }
              result++;
          }
          q = q->right;
      }
      if (w1-v != p->number) { fprintf(stderr, "oh! %d %d\n", (int)(w1-v), p->number); exit(1); }
      if (backward) for (w0 = v; w0 < w1; w0++) reverse_b(w0->b);
      qsort(v, w1 - v, sizeof(struct amongvec), compare_amongvec);
  
      /* the following loop is O(n squared) */
      for (w0 = w1 - 1; w0 >= v; w0--) {
          symbol * b = w0->b;
          int size = w0->size;
          struct amongvec * w;
  
          for (w = w0 - 1; w >= v; w--) {
              if (w->size < size && memcmp(w->b, b, w->size * sizeof(symbol)) == 0) {
                  w0->i = w - v;  /* fill in index of longest substring */
                  break;
              }
          }
      }
      if (backward) for (w0 = v; w0 < w1; w0++) reverse_b(w0->b);
  
      for (w0 = v; w0 < w1 - 1; w0++)
          if (w0->size == (w0 + 1)->size &&
              memcmp(w0->b, (w0 + 1)->b, w0->size * sizeof(symbol)) == 0) {
  	    error3(a, (w0 + 1)->p, (w0 + 1)->b);
  	    error3a(a, w0->p);
  	}
  
      x->literalstring_count = p->number;
      x->command_count = result - 1;
      p->among = x;
  
      x->substring = substring;
      if (substring != 0) substring->among = x;
      if (x->command_count != 0 || x->starter != 0) a->amongvar_needed = true;
  }
  
  static struct node * read_among(struct analyser * a) {
      struct tokeniser * t = a->tokeniser;
      struct node * p = new_node(a, c_among);
      struct node * p_end = 0;
      int previous_token = -1;
      struct node * substring = a->substring;
  
      a->substring = 0;
      p->number = 0; /* counts the number of literals */
      if (!get_token(a, c_bra)) return p;
      while (true) {
          struct node * q;
          int token = read_token(t);
          switch (token) {
              case c_literalstring:
                  q = read_literalstring(a);
                  if (read_token(t) == c_name) {
                      struct node * r = new_node(a, c_name);
                      name_to_node(a, r, 'r');
                      q->left = r;
                  }
                  else t->token_held = true;
                  p->number++; break;
              case c_bra:
                  if (previous_token == c_bra) error(a, e_adjacent_bracketed_in_among);
                  q = read_C_list(a); break;
              default:
                  error(a, e_unexpected_token_in_among);
              case c_ket:
                  if (p->number == 0) error(a, e_empty_among);
                  if (t->error_count == 0) make_among(a, p, substring);
                  return p;
          }
          previous_token = token;
          if (p_end == 0) p->left = q; else p_end->right = q;
          p_end = q;
      }
  }
  
  static struct node * read_substring(struct analyser * a) {
  
      struct node * p = new_node(a, c_substring);
      if (a->substring != 0) error2(a, e_substring_preceded_by_substring, a->substring->line_number);
      a->substring = p;
      return p;
  }
  
  static void check_modifyable(struct analyser * a) {
      if (!a->modifyable) error(a, e_not_allowed_inside_reverse);
  }
  
  static struct node * read_C(struct analyser * a) {
      struct tokeniser * t = a->tokeniser;
      int token = read_token(t);
      switch (token) {
          case c_bra:
              return read_C_list(a);
          case c_backwards:
              {
                  int mode = a->mode;
                  if (a->mode == m_backward) error(a, e_already_backwards); else a->mode = m_backward;
                  {   struct node * p = C_style(a, "C", token);
                      a->mode = mode;
                      return p;
                  }
              }
          case c_reverse:
              {
                  int mode = a->mode;
                  int modifyable = a->modifyable;
                  a->modifyable = false;
                  a->mode = mode == m_forward ? m_backward : m_forward;
                  {
                      struct node * p = C_style(a, "C", token);
                      a->mode = mode;
                      a->modifyable = modifyable;
                      return p;
                  }
              }
          case c_not:
          case c_try:
          case c_fail:
          case c_test:
          case c_do:
          case c_goto:
          case c_gopast:
          case c_repeat:
              return C_style(a, "C", token);
          case c_loop:
          case c_atleast:
              return C_style(a, "AC", token);
          case c_setmark:
              return C_style(a, "i", token);
          case c_tomark:
          case c_atmark:
          case c_hop:
              return C_style(a, "A", token);
          case c_delete:
              check_modifyable(a);
          case c_next:
          case c_tolimit:
          case c_atlimit:
          case c_leftslice:
          case c_rightslice:
          case c_true:
          case c_false:
          case c_debug:
              return C_style(a, "", token);
          case c_assignto:
          case c_sliceto:
              check_modifyable(a);
              return C_style(a, "s", token);
          case c_assign:
          case c_insert:
          case c_attach:
          case c_slicefrom:
              check_modifyable(a);
              return C_style(a, "S", token);
          case c_setlimit:
              return C_style(a, "CfD", token);
          case c_set:
          case c_unset:
              return C_style(a, "b", token);
          case c_dollar:
              get_token(a, c_name);
              {
                  struct node * p;
                  struct name * q = find_name(a);
                  int mode = a->mode;
                  int modifyable = a->modifyable;
                  switch (q ? q->type : t_string)
                      /* above line was: switch (q->type) - bug #1 fix 7/2/2003 */
                  {
                      default: error(a, e_not_of_type_string_or_integer);
                      case t_string:
                          a->mode = m_forward;
                          a->modifyable = true;
                          p = new_node(a, c_dollar);
                          p->left = read_C(a); break;
                      case t_integer:
                      /*  a->mode = m_integer;  */
                          p = new_node(a, read_AE_test(a));
                          p->AE = read_AE(a, 0); break;
                  }
                  if (q) mark_used_in(a, q, p);
                  p->name = q;
                  a->mode = mode;
                  a->modifyable = modifyable;
                  return p;
              }
          case c_name:
              {
                  struct name * q = find_name(a);
                  struct node * p = new_node(a, c_name);
                  if (q) {
                      mark_used_in(a, q, p);
                      switch (q->type) {
                          case t_boolean:
                              p->type = c_booltest; break;
                          case t_integer:
                              error(a, e_misplaced); /* integer name misplaced */
                          case t_string:
                              break;
                          case t_routine:
                          case t_external:
                              p->type = c_call;
                              check_routine_mode(a, q, a->mode);
                              break;
                          case t_grouping:
                              p->type = c_grouping; break;
                      }
                  }
                  p->name = q;
                  return p;
              }
          case c_non:
              {
                  struct node * p = new_node(a, token);
                  read_token(t);
                  if (t->token == c_minus) read_token(t);
                  if (!check_token(a, c_name)) { omission_error(a, c_name); return p; }
                  name_to_node(a, p, 'g');
                  return p;
              }
          case c_literalstring:
              return read_literalstring(a);
          case c_among: return read_among(a);
          case c_substring: return read_substring(a);
          default: error(a, e_unexpected_token); return 0;
      }
  }
  
  static int next_symbol(symbol * p, symbol * W, int utf8) {
      if (utf8) {
          int ch;
          int j = get_utf8(p, & ch);
          W[0] = ch; return j;
      } else {
          W[0] = p[0]; return 1;
      }
  }
  
  static symbol * alter_grouping(symbol * p, symbol * q, int style, int utf8) {
      int j = 0;
      symbol W[1];
      int width;
      if (style == c_plus) {
          while (j < SIZE(q)) {
              width = next_symbol(q + j, W, utf8);
              p = add_to_b(p, 1, W);
              j += width;
          }
      } else {
          while (j < SIZE(q)) {
              int i;
              width = next_symbol(q + j, W, utf8);
              for (i = 0; i < SIZE(p); i++) {
                  if (p[i] == W[0]) {
                      memmove(p + i, p + i + 1, (SIZE(p) - i - 1) * sizeof(symbol));
                      SIZE(p)--;
                  }
              }
              j += width;
          }
      }
      return p;
  }
  
  static void read_define_grouping(struct analyser * a, struct name * q) {
      struct tokeniser * t = a->tokeniser;
      int style = c_plus;
      {
          NEW(grouping, p);
          if (a->groupings == 0) a->groupings = p; else a->groupings_end->next = p;
          a->groupings_end = p;
          q->grouping = p;
          p->next = 0;
          p->name = q;
          p->number = q->count;
          p->b = create_b(0);
          while (true) {
              switch (read_token(t)) {
                  case c_name:
                      {
                          struct name * r = find_name(a);
                          if (r) {
                              check_name_type(a, r, 'g');
                              p->b = alter_grouping(p->b, r->grouping->b, style, false);
                          }
                      }
                      break;
                  case c_literalstring:
                      p->b = alter_grouping(p->b, t->b, style, a->utf8);
                      break;
                  default: error(a, e_unexpected_token); return;
              }
              switch (read_token(t)) {
                  case c_plus:
                  case c_minus: style = t->token; break;
                  default: goto label0;
              }
          }
      label0:
          {
              int i;
              int max = 0;
              int min = 1<<16;
              for (i = 0; i < SIZE(p->b); i++) {
                  if (p->b[i] > max) max = p->b[i];
                  if (p->b[i] < min) min = p->b[i];
              }
              p->largest_ch = max;
              p->smallest_ch = min;
              if (min == 1<<16) error(a, e_empty_grouping);
          }
          t->token_held = true; return;
      }
  }
  
  static void read_define_routine(struct analyser * a, struct name * q) {
      struct node * p = new_node(a, c_define);
      a->amongvar_needed = false;
      if (q) {
          check_name_type(a, q, 'R');
          if (q->definition != 0) error(a, e_redefined);
          if (q->mode < 0) q->mode = a->mode; else
          if (q->mode != a->mode) error2(a, e_declared_as_different_mode, q->mode);
      }
      p->name = q;
      if (a->program == 0) a->program = p; else a->program_end->right = p;
      a->program_end = p;
      get_token(a, c_as);
      p->left = read_C(a);
      if (q) q->definition = p->left;
  
      if (a->substring != 0) {
           error2(a, e_unresolved_substring, a->substring->line_number);
           a->substring = 0;
      }
      p->amongvar_needed = a->amongvar_needed;
  }
  
  static void read_define(struct analyser * a) {
      if (get_token(a, c_name)) {
          struct name * q = find_name(a);
          if (q != 0 && q->type == t_grouping) read_define_grouping(a, q);
              else read_define_routine(a, q);
      }
  }
  
  static void read_backwardmode(struct analyser * a) {
      int mode = a->mode;
      a->mode = m_backward;
      if (get_token(a, c_bra)) {
          read_program_(a, c_ket);
          check_token(a, c_ket);
      }
      a->mode = mode;
  }
  
  static void read_program_(struct analyser * a, int terminator) {
      struct tokeniser * t = a->tokeniser;
      while (true) {
          switch (read_token(t)) {
              case c_strings:     read_names(a, t_string); break;
              case c_booleans:    read_names(a, t_boolean); break;
              case c_integers:    read_names(a, t_integer); break;
              case c_routines:    read_names(a, t_routine); break;
              case c_externals:   read_names(a, t_external); break;
              case c_groupings:   read_names(a, t_grouping); break;
              case c_define:      read_define(a); break;
              case c_backwardmode:read_backwardmode(a); break;
              case c_ket:
                  if (terminator == c_ket) return;
              default:
                  error(a, e_unexpected_token); break;
              case -1:
                  if (terminator >= 0) omission_error(a, c_ket);
                  return;
          }
      }
  }
  
  extern void read_program(struct analyser * a) {
      read_program_(a, -1);
      {
          struct name * q = a->names;
          while (q) {
              switch (q->type) {
                  case t_external: case t_routine:
                      if (q->used && q->definition == 0) error4(a, q); break;
                  case t_grouping:
                      if (q->used && q->grouping == 0) error4(a, q); break;
              }
              q = q->next;
          }
      }
  
      if (a->tokeniser->error_count == 0) {
          struct name * q = a->names;
          int warned = false;
          while (q) {
              if (!q->referenced) {
                  if (!warned) {
                      fprintf(stderr, "Declared but not used:");
                      warned = true;
                  }
                  fprintf(stderr, " "); report_b(stderr, q->b);
              }
              q = q->next;
          }
          if (warned) fprintf(stderr, "\n");
  
          q = a->names;
          warned = false;
          while (q) {
              if (! q->used && (q->type == t_routine ||
                                q->type == t_grouping)) {
                  if (!warned) {
                      fprintf(stderr, "Declared and defined but not used:");
                      warned = true;
                  }
                  fprintf(stderr, " "); report_b(stderr, q->b);
              }
              q = q->next;
          }
          if (warned) fprintf(stderr, "\n");
      }
  }
  
  extern struct analyser * create_analyser(struct tokeniser * t) {
      NEW(analyser, a);
      a->tokeniser = t;
      a->nodes = 0;
      a->names = 0;
      a->literalstrings = 0;
      a->program = 0;
      a->amongs = 0;
      a->among_count = 0;
      a->groupings = 0;
      a->mode = m_forward;
      a->modifyable = true;
      { int i; for (i = 0; i < t_size; i++) a->name_count[i] = 0; }
      a->substring = 0;
      a->int_limits_used = false;
      return a;
  }
  
  extern void close_analyser(struct analyser * a) {
      {
          struct node * q = a->nodes;
          while (q) {
              struct node * q_next = q->next;
              FREE(q);
              q = q_next;
          }
      }
      {
          struct name * q = a->names;
          while (q) {
              struct name * q_next = q->next;
              lose_b(q->b); FREE(q);
              q = q_next;
          }
      }
      {
          struct literalstring * q = a->literalstrings;
          while (q) {
              struct literalstring * q_next = q->next;
              lose_b(q->b); FREE(q);
              q = q_next;
          }
      }
      {
          struct among * q = a->amongs;
          while (q) {
              struct among * q_next = q->next;
              FREE(q->b); FREE(q);
              q = q_next;
          }
      }
      {
          struct grouping * q = a->groupings;
          while (q) {
              struct grouping * q_next = q->next;
              lose_b(q->b); FREE(q);
              q = q_next;
          }
      }
      FREE(a);
  }
  
  