static unsigned ts_parser__condense_stack()

in lib/src/parser.c [1415:1499]

• 78 lines of code
• 20 McCabe index (conditional complexity)

static unsigned ts_parser__condense_stack(TSParser *self) {
  bool made_changes = false;
  unsigned min_error_cost = UINT_MAX;
  for (StackVersion i = 0; i < ts_stack_version_count(self->stack); i++) {
    if (ts_stack_is_halted(self->stack, i)) {
      ts_stack_remove_version(self->stack, i);
      i--;
      continue;
    }

    ErrorStatus status_i = ts_parser__version_status(self, i);
    if (!status_i.is_in_error && status_i.cost < min_error_cost) {
      min_error_cost = status_i.cost;
    }

    for (StackVersion j = 0; j < i; j++) {
      ErrorStatus status_j = ts_parser__version_status(self, j);

      switch (ts_parser__compare_versions(self, status_j, status_i)) {
        case ErrorComparisonTakeLeft:
          made_changes = true;
          ts_stack_remove_version(self->stack, i);
          i--;
          j = i;
          break;
        case ErrorComparisonPreferLeft:
        case ErrorComparisonNone:
          if (ts_stack_merge(self->stack, j, i)) {
            made_changes = true;
            i--;
            j = i;
          }
          break;
        case ErrorComparisonPreferRight:
          made_changes = true;
          if (ts_stack_merge(self->stack, j, i)) {
            i--;
            j = i;
          } else {
            ts_stack_swap_versions(self->stack, i, j);
          }
          break;
        case ErrorComparisonTakeRight:
          made_changes = true;
          ts_stack_remove_version(self->stack, j);
          i--;
          j--;
          break;
      }
    }
  }

  while (ts_stack_version_count(self->stack) > MAX_VERSION_COUNT) {
    ts_stack_remove_version(self->stack, MAX_VERSION_COUNT);
    made_changes = true;
  }

  if (ts_stack_version_count(self->stack) > 0) {
    bool has_unpaused_version = false;
    for (StackVersion i = 0, n = ts_stack_version_count(self->stack); i < n; i++) {
      if (ts_stack_is_paused(self->stack, i)) {
        if (!has_unpaused_version && self->accept_count < MAX_VERSION_COUNT) {
          LOG("resume version:%u", i);
          min_error_cost = ts_stack_error_cost(self->stack, i);
          TSSymbol lookahead_symbol = ts_stack_resume(self->stack, i);
          ts_parser__handle_error(self, i, lookahead_symbol);
          has_unpaused_version = true;
        } else {
          ts_stack_remove_version(self->stack, i);
          i--;
          n--;
        }
      } else {
        has_unpaused_version = true;
      }
    }
  }

  if (made_changes) {
    LOG("condense");
    LOG_STACK();
  }

  return min_error_cost;
}