ready to build AST

src/semantic/semantic.cpp

@@ -3,15 +3,37 @@
 #include "MXLexer.h"
 #include "MXParser.h"
 #include "antlr4-runtime.h"
+#include "ast/ast.h"
 #include "visitor.h"
-int SemanticCheck(std::istream &fin) {
+
+class MXErrorListener : public antlr4::BaseErrorListener {
+  bool no_problem;
+
+ public:
+  MXErrorListener() : no_problem(true) {}
+  void syntaxError(antlr4::Recognizer *recognizer, antlr4::Token *offendingSymbol, size_t line,
+                   size_t charPositionInLine, const std::string &msg, std::exception_ptr e) override {
+    std::cout << "line " << line << ":" << charPositionInLine << " AT "
+              << offendingSymbol->getText() << ": " << msg << std::endl;
+    no_problem = false;
+  }
+  bool IsOk() { return no_problem; }
+};
+std::shared_ptr<ASTNodeBase> BuildAST(Visitor *visitor, antlr4::tree::ParseTree *tree) { ; }
+std::shared_ptr<ASTNodeBase> CheckAndDecorate(std::shared_ptr<ASTNodeBase> src) { ; }
+
+void SemanticCheck(std::istream &fin, std::shared_ptr<ASTNodeBase> &ast_out) {
   antlr4::ANTLRInputStream input(fin);
   MXLexer lexer(&input);
   antlr4::CommonTokenStream tokens(&lexer);
   tokens.fill();
   MXParser parser(&tokens);
+  parser.removeErrorListeners();
+  MXErrorListener error_listener;
+  parser.addErrorListener(&error_listener);
   antlr4::tree::ParseTree *tree = parser.mxprog();
+  if (!error_listener.IsOk()) throw SemanticError("Fatal error: syntax error", 1);
   Visitor visitor;
-  visitor.visit(tree);
-  return 0;
+  std::shared_ptr<ASTNodeBase> ast = BuildAST(&visitor, tree);
+  ast_out = CheckAndDecorate(ast);
 }