[Tolk] Implement AST: intermediate representation of tolk files

Now, the whole .tolk file can be loaded as AST tree and
then converted to Expr/Op.
This gives a great ability to implement AST transformations.
In the future, more and more code analysis will be moved out of legacy to AST-level.

tolk/ast.cpp

@@ -0,0 +1,70 @@
+/*
+    This file is part of TON Blockchain Library.
+
+    TON Blockchain Library is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation, either version 2 of the License, or
+    (at your option) any later version.
+
+    TON Blockchain Library is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with TON Blockchain Library.  If not, see <http://www.gnu.org/licenses/>.
+*/
+#include "ast.h"
+#include "ast-stringifier.h"
+#include <iostream>
+
+namespace tolk {
+
+static_assert(sizeof(ASTNodeBase) == 12);
+
+#ifdef TOLK_DEBUG
+
+std::string ASTNodeBase::to_debug_string(bool colored) const {
+  ASTStringifier s(colored);
+  return s.to_string_with_children(this);
+}
+
+void ASTNodeBase::debug_print() const {
+  std::cerr << to_debug_string(true) << std::endl;
+}
+
+#endif  // TOLK_DEBUG
+
+UnexpectedASTNodeType::UnexpectedASTNodeType(AnyV v_unexpected, const char* place_where): v_unexpected(v_unexpected) {
+  message = "Unexpected ASTNodeType ";
+#ifdef TOLK_DEBUG
+  message += ASTStringifier::ast_node_type_to_string(v_unexpected->type);
+  message += " ";
+#endif
+  message += "in ";
+  message += place_where;
+}
+
+void ASTNodeBase::error(const std::string& err_msg) const {
+  throw ParseError(loc, err_msg);
+}
+
+int Vertex<ast_forall_list>::lookup_idx(std::string_view nameT) const {
+  for (size_t idx = 0; idx < children.size(); ++idx) {
+    if (children[idx] && children[idx]->as<ast_forall_item>()->nameT == nameT) {
+      return static_cast<int>(idx);
+    }
+  }
+  return -1;
+}
+
+int Vertex<ast_argument_list>::lookup_idx(std::string_view arg_name) const {
+  for (size_t idx = 0; idx < children.size(); ++idx) {
+    if (children[idx] && children[idx]->as<ast_argument>()->arg_name == arg_name) {
+      return static_cast<int>(idx);
+    }
+  }
+  return -1;
+}
+
+} // namespace tolk