Method PostVisitIdent

eval/compiler/flat_expr_builder.cc:794–899

Ident node handler. Invoked after child nodes are processed.

  // Ident node handler.
  // Invoked after child nodes are processed.
  void PostVisitIdent(const cel::Expr& expr,
                      const cel::IdentExpr& ident_expr) override {
    if (!progress_status_.ok()) {
      return;
    }
    absl::string_view path = ident_expr.name();
    if (!ValidateOrError(
            !path.empty(),
            "Invalid expression: identifier 'name' must not be empty")) {
      return;
    }

    // Check if this is a local variable first (since it should shadow most
    // other interpretations).
    SlotLookupResult slot = LookupSlot(path);

    if (slot.subexpression >= 0) {
      auto* subexpression =
          program_builder_.GetExtractedSubexpression(slot.subexpression);
      if (subexpression == nullptr) {
        SetProgressStatusError(
            absl::InternalError("bad subexpression reference"));
        return;
      }
      if (subexpression->IsRecursive()) {
        const auto& program = subexpression->recursive_program();
        SetRecursiveStep(
            CreateDirectLazyInitStep(slot.slot, program.step.get(), expr.id()),
            program.depth + 1);
      } else {
        // Off by one since mainline expression will be index 0.
        AddStep(
            CreateLazyInitStep(slot.slot, slot.subexpression + 1, expr.id()));
      }
      return;
    } else if (slot.slot >= 0) {
      if (options_.max_recursion_depth != 0) {
        SetRecursiveStep(
            CreateDirectSlotIdentStep(ident_expr.name(), slot.slot, expr.id()),
            1);
      } else {
        AddStep(
            CreateIdentStepForSlot(ident_expr.name(), slot.slot, expr.id()));
      }
      return;
    }

    // Attempt to resolve a select expression as a namespaced identifier for an
    // enum or type constant value.
    absl::optional<cel::Value> const_value;
    int64_t select_root_id = -1;
    std::string path_candidate;

    while (!namespace_stack_.empty()) {
      const auto& select_node = namespace_stack_.front();
      // Generate path in format "<ident>.<field 0>.<field 1>...".
      const cel::Expr* select_expr = select_node.first;
      path_candidate = absl::StrCat(path, ".", select_node.second);