avoid recursion and ambiguity

bootstrap/emit.cc

@@ -21,8 +21,8 @@ std::any EmitVisitor::visitFunction(xlangParser::FunctionContext *ctx) {
          << "export function w $" << ctx->Identifier()->getSymbol()->getText()
          << "(";
   if (auto param_list = ctx->parameterList()) {
-    for (const auto param : param_list->Identifier()) {
+    for (auto param : param_list->parameter()) {
-      output << "w %_" << param->getSymbol()->getText() << ", ";
+      output << "w %_" << param->Identifier()->getSymbol()->getText() << ", ";
     }
   }
   output << ")" << std::endl << "{" << std::endl << "@start" << std::endl;
@@ -36,10 +36,9 @@ std::any EmitVisitor::visitFunction(xlangParser::FunctionContext *ctx) {
 std::any EmitVisitor::visitStatement(xlangParser::StatementContext *ctx) {
   if (ctx->If()) {
     int block = blockcount++;
-
     output << "@if" << block << "_expr" << std::endl;
     tmpcount = 0;
-    visitCondition(ctx->condition());
+    visitExpr(ctx->expr(0));
     output << "  jnz " << last << ", @if" << block << "_then, @if" << block
            << "_else" << std::endl;
     output << "@if" << block << "_then" << std::endl;
@@ -54,12 +53,11 @@ std::any EmitVisitor::visitStatement(xlangParser::StatementContext *ctx) {
   }
   if (ctx->While()) {
     int block = blockcount++;
-
     loopstack.push_back(block);
     output << "@loop" << block << "_continue" << std::endl;
     output << "@loop" << block << "_expr" << std::endl;
     tmpcount = 0;
-    visitCondition(ctx->condition());
+    visitExpr(ctx->expr(0));
     output << "  jnz " << last << ", @loop" << block << "_body, @loop" << block
            << "_end" << std::endl;
     output << "@loop" << block << "_body" << std::endl;
@@ -71,20 +69,19 @@ std::any EmitVisitor::visitStatement(xlangParser::StatementContext *ctx) {
   }
   if (ctx->For()) {
     int block = blockcount++;
-
     loopstack.push_back(block);
     tmpcount = 0;
-    visitValue(ctx->value(0));
+    visitExpr(ctx->expr(0));
     output << "@loop" << block << "_expr" << std::endl;
     tmpcount = 0;
-    visitCondition(ctx->condition());
+    visitExpr(ctx->expr(1));
     output << "  jnz " << last << ", @loop" << block << "_body, @loop" << block
            << "_end" << std::endl;
     output << "@loop" << block << "_body" << std::endl;
     visitBlock(ctx->block(0));
     output << "@loop" << block << "_continue" << std::endl;
     tmpcount = 0;
-    visitValue(ctx->value(1));
+    visitExpr(ctx->expr(2));
     output << "  jmp @loop" << block << "_expr" << std::endl;
     output << "@loop" << block << "_end" << std::endl;
     loopstack.pop_back();
@@ -114,44 +111,74 @@ std::any EmitVisitor::visitStatement(xlangParser::StatementContext *ctx) {
   }
   if (ctx->Return()) {
     tmpcount = 0;
-    visitValue(ctx->value(0));
+    visitExpr(ctx->expr(0));
     output << "  ret " << last << std::endl;
     output << "@dead" << blockcount++ << std::endl;
     return {};
   }
   if (ctx->Print()) {
     tmpcount = 0;
-    visitValue(ctx->value(0));
+    visitExpr(ctx->expr(0));
     output << "  call $printf(l $printformat, ..., w " << last << ")"
            << std::endl;
     return {};
   }
-  visitValue(ctx->value(0));
+  visitExpr(ctx->expr(0));
   return {};
 }
 
-#define OPERATOR(Operator, visitLeft, left, visitRight, right, ssa_op) \
+std::any EmitVisitor::visitExpr(xlangParser::ExprContext *ctx) {
-  if (ctx->Operator()) {                                               \
+  if (auto op = ctx->assignmentOp()) {
-    visitLeft(ctx->left);                                              \
+    auto name = ctx->Identifier()->getSymbol()->getText();
-    std::string l = last;                                              \
+    if (op->Define() || op->Assign()) {
-    visitRight(ctx->right);                                            \
+      visitExpr(ctx->expr());
-    std::string r = last;                                              \
+      output << "  %_" << name << " = w copy " << last << std::endl;
-    output << "  " << tmp() << " = w " ssa_op " " << l << ", " << r    \
+      last = "%_" + name;
-           << std::endl;                                               \
+      return {};
-    return {};                                                         \
+    }
+    if (op->Increment()) {
+      visitExpr(ctx->expr());
+      output << "  %_" << name << " = w add %_" << name << ", " << last
+             << std::endl;
+      last = "%_" + name;
+      return {};
+    }
+    if (op->Decrement()) {
+      visitExpr(ctx->expr());
+      output << "  %_" << name << " = w sub %_" << name << ", " << last
+             << std::endl;
+      last = "%_" + name;
+      return {};
+    }
+  }
+  visitBooleanExpr(ctx->booleanExpr());
+  return {};
+}
+
+#define OPERATOR(Operator, ssa_op)                                         \
+  if (op->Operator()) {                                                    \
+    output << "  " << tmp() << " = w " ssa_op " " << left << ", " << right \
+           << std::endl;                                                   \
   }
 
-std::any EmitVisitor::visitCondition(xlangParser::ConditionContext *ctx) {
+std::any EmitVisitor::visitBooleanExpr(xlangParser::BooleanExprContext *ctx) {
-  OPERATOR(And, visitCondition, condition(), visitBoolean, boolean(), "and");
+  visitComparisonExpr(ctx->comparisonExpr(0));
-  OPERATOR(Or, visitCondition, condition(), visitBoolean, boolean(), "or");
+  for (size_t i = 0, n = ctx->booleanOp().size(); i < n; i++) {
-  OPERATOR(Xor, visitCondition, condition(), visitBoolean, boolean(), "xor");
+    std::string left = last;
-  visitBoolean(ctx->boolean());
+    visitComparisonExpr(ctx->comparisonExpr(i + 1));
+    std::string right = last;
+    auto op = ctx->booleanOp(i);
+    OPERATOR(And, "and");
+    OPERATOR(Or, "or");
+    OPERATOR(Xor, "xor");
+  }
   return {};
 }
 
-std::any EmitVisitor::visitBoolean(xlangParser::BooleanContext *ctx) {
+std::any EmitVisitor::visitComparisonExpr(
+    xlangParser::ComparisonExprContext *ctx) {
   if (ctx->Not()) {
-    visitBoolean(ctx->boolean());
+    visitComparisonExpr(ctx->comparisonExpr());
     std::string b = last;
     output << "  " << tmp() << " = w xor 1, " << b << std::endl;
     return {};
@@ -164,33 +191,51 @@ std::any EmitVisitor::visitBoolean(xlangParser::BooleanContext *ctx) {
     last = "0";
     return {};
   }
-  OPERATOR(Less, visitExpr, expr(0), visitExpr, expr(1), "csltw");
+  visitAdditiveExpr(ctx->additiveExpr(0));
-  OPERATOR(LessEqual, visitExpr, expr(0), visitExpr, expr(1), "cslew");
+  if (auto op = ctx->comparisonOp()) {
-  OPERATOR(Greater, visitExpr, expr(0), visitExpr, expr(1), "csgtw");
+    std::string left = last;
-  OPERATOR(GreaterEqual, visitExpr, expr(0), visitExpr, expr(1), "csgew");
+    visitAdditiveExpr(ctx->additiveExpr(1));
-  OPERATOR(Equal, visitExpr, expr(0), visitExpr, expr(1), "ceqw");
+    std::string right = last;
-  OPERATOR(NotEqual, visitExpr, expr(0), visitExpr, expr(1), "cnew");
+    OPERATOR(Less, "csltw");
-  visitChildren(ctx);
+    OPERATOR(LessEqual, "cslew");
+    OPERATOR(Greater, "csgtw");
+    OPERATOR(GreaterEqual, "csgew");
+    OPERATOR(Equal, "ceqw");
+    OPERATOR(NotEqual, "cnew");
+  }
   return {};
 }
 
-std::any EmitVisitor::visitExpr(xlangParser::ExprContext *ctx) {
+std::any EmitVisitor::visitAdditiveExpr(xlangParser::AdditiveExprContext *ctx) {
-  OPERATOR(Plus, visitExpr, expr(), visitTerm, term(), "add");
+  visitMultiplicativeExpr(ctx->multiplicativeExpr(0));
-  OPERATOR(Minus, visitExpr, expr(), visitTerm, term(), "sub");
+  for (size_t i = 0, n = ctx->additiveOp().size(); i < n; i++) {
-  OPERATOR(BitAnd, visitExpr, expr(), visitTerm, term(), "and");
+    std::string left = last;
-  OPERATOR(BitOr, visitExpr, expr(), visitTerm, term(), "or");
+    visitMultiplicativeExpr(ctx->multiplicativeExpr(i + 1));
-  OPERATOR(BitXor, visitExpr, expr(), visitTerm, term(), "xor");
+    std::string right = last;
-  OPERATOR(ShiftLeft, visitExpr, expr(), visitTerm, term(), "shl");
+    auto op = ctx->additiveOp(i);
-  OPERATOR(ShiftRight, visitExpr, expr(), visitTerm, term(), "shr");
+    OPERATOR(Plus, "add");
-  visitTerm(ctx->term());
+    OPERATOR(Minus, "sub");
+    OPERATOR(BitAnd, "and");
+    OPERATOR(BitOr, "or");
+    OPERATOR(BitXor, "xor");
+    OPERATOR(ShiftLeft, "shl");
+    OPERATOR(ShiftRight, "shr");
+  }
   return {};
 }
 
-std::any EmitVisitor::visitTerm(xlangParser::TermContext *ctx) {
+std::any EmitVisitor::visitMultiplicativeExpr(
-  OPERATOR(Mul, visitTerm, term(), visitFactor, factor(), "mul");
+    xlangParser::MultiplicativeExprContext *ctx) {
-  OPERATOR(Div, visitTerm, term(), visitFactor, factor(), "div");
+  visitFactor(ctx->factor(0));
-  OPERATOR(Rem, visitTerm, term(), visitFactor, factor(), "rem");
+  for (size_t i = 0, n = ctx->multiplicativeOp().size(); i < n; i++) {
-  visitFactor(ctx->factor());
+    std::string left = last;
+    visitFactor(ctx->factor(i + 1));
+    std::string right = last;
+    auto op = ctx->multiplicativeOp(i);
+    OPERATOR(Mul, "mul");
+    OPERATOR(Div, "div");
+    OPERATOR(Rem, "rem");
+  }
   return {};
 }
 
@@ -211,50 +256,28 @@ std::any EmitVisitor::visitFactor(xlangParser::FactorContext *ctx) {
     last = integer->getSymbol()->getText();
     return {};
   }
-  visitChildren(ctx);
+  if (auto identifier = ctx->Identifier()) {
-  return {};
+    auto name = identifier->getSymbol()->getText();
-}
+    if (ctx->LeftParen()) {
-
+      std::vector<std::string> args;
-std::any EmitVisitor::visitVariable(xlangParser::VariableContext *ctx) {
+      if (auto arg_list = ctx->argumentList()) {
-  auto name = ctx->Identifier()->getSymbol()->getText();
+        for (auto expr : arg_list->expr()) {
-
+          visitExpr(expr);
-  if (ctx->Define() || ctx->Assign()) {
+          args.emplace_back(last);
-    visitValue(ctx->value());
+        }
-    output << "  %_" << name << " = w copy " << last << std::endl;
-    last = "%_" + name;
-    return {};
-  }
-  if (ctx->Increment()) {
-    visitExpr(ctx->expr());
-    output << "  %_" << name << " = w add %_" << name << ", " << last
-           << std::endl;
-    last = "%_" + name;
-    return {};
-  }
-  if (ctx->Decrement()) {
-    visitExpr(ctx->expr());
-    output << "  %_" << name << " = w sub %_" << name << ", " << last
-           << std::endl;
-    last = "%_" + name;
-    return {};
-  }
-  if (ctx->LeftParen()) {
-    std::vector<std::string> args;
-
-    if (auto arg_list = ctx->argumentList()) {
-      for (auto value : arg_list->value()) {
-        visitValue(value);
-        args.emplace_back(last);
       }
+      output << "  " << tmp() << " = w call $" << name << "(";
+      for (auto arg : args) {
+        output << "w " << arg << ", ";
+      }
+      output << ")" << std::endl;
+      return {};
+    } else {
+      last = "%_" + name;
+      return {};
     }
-    output << "  " << tmp() << " = w call $" << name << "(";
-    for (auto arg : args) {
-      output << "w " << arg << ", ";
-    }
-    output << ")" << std::endl;
-    return {};
   }
-  last = "%_" + name;
+  visitExpr(ctx->expr());
   return {};
 }
 

bootstrap/emit.hh

@@ -22,12 +22,14 @@ class EmitVisitor : public xlangBaseVisitor {
   std::any visitFile(xlangParser::FileContext *ctx) override;
   std::any visitFunction(xlangParser::FunctionContext *ctx) override;
   std::any visitStatement(xlangParser::StatementContext *ctx) override;
-  std::any visitCondition(xlangParser::ConditionContext *ctx) override;
-  std::any visitBoolean(xlangParser::BooleanContext *ctx) override;
   std::any visitExpr(xlangParser::ExprContext *ctx) override;
-  std::any visitTerm(xlangParser::TermContext *ctx) override;
+  std::any visitBooleanExpr(xlangParser::BooleanExprContext *ctx) override;
+  std::any visitComparisonExpr(
+      xlangParser::ComparisonExprContext *ctx) override;
+  std::any visitAdditiveExpr(xlangParser::AdditiveExprContext *ctx) override;
+  std::any visitMultiplicativeExpr(
+      xlangParser::MultiplicativeExprContext *ctx) override;
   std::any visitFactor(xlangParser::FactorContext *ctx) override;
-  std::any visitVariable(xlangParser::VariableContext *ctx) override;
 };
 
 }  // namespace xlang

bootstrap/typecheck.cc

@@ -22,16 +22,15 @@ std::any TypeCheckVisitor::visitFile(xlangParser::FileContext *ctx) {
   for (auto function : ctx->function()) {
     auto token = function->Identifier()->getSymbol();
     auto name = token->getText();
-    Signature signature{std::any_cast<Type>(visitType(function->type())), {}};
-
     if (signatures.find(name) != signatures.end()) {
       errorlistener.duplicateFunction(token, name);
       continue;
     }
+    Signature signature{std::any_cast<Type>(visitType(function->type())), {}};
     if (auto param_list = function->parameterList()) {
-      for (auto type : param_list->type()) {
+      for (auto param : param_list->parameter()) {
         signature.parametertypes.push_back(
-            std::any_cast<Type>(visitType(type)));
+            std::any_cast<Type>(visitType(param->type())));
       }
     }
     signatures.emplace(name, signature);
@@ -43,10 +42,9 @@ std::any TypeCheckVisitor::visitFile(xlangParser::FileContext *ctx) {
 std::any TypeCheckVisitor::visitFunction(xlangParser::FunctionContext *ctx) {
   scope.enter();
   if (auto param_list = ctx->parameterList()) {
-    for (size_t i = 0, n = param_list->Identifier().size(); i < n; i++) {
+    for (auto param : param_list->parameter()) {
-      auto name = param_list->Identifier(i)->getSymbol()->getText();
+      auto name = param->Identifier()->getSymbol()->getText();
-      auto type = std::any_cast<Type>(visitType(param_list->type(i)));
+      auto type = std::any_cast<Type>(visitType(param->type()));
-
       scope.add(name, type);
     }
   }
@@ -77,10 +75,10 @@ std::any TypeCheckVisitor::visitBlock(xlangParser::BlockContext *ctx) {
 std::any TypeCheckVisitor::visitStatement(xlangParser::StatementContext *ctx) {
   if (ctx->If()) {
     scope.enter();
-    auto condition = ctx->condition();
+    auto expr = ctx->expr(0);
-    auto type = std::any_cast<Type>(visitCondition(condition));
+    auto type = std::any_cast<Type>(visitExpr(expr));
     if (type != Type::Boolean) {
-      errorlistener.typeMismatch(condition->getStart(), Type::Boolean, type);
+      errorlistener.typeMismatch(expr->getStart(), Type::Boolean, type);
     }
     visitBlock(ctx->block(0));
     if (ctx->Else()) {
@@ -89,19 +87,28 @@ std::any TypeCheckVisitor::visitStatement(xlangParser::StatementContext *ctx) {
     scope.leave();
     return {};
   }
-  if (ctx->While() || ctx->For()) {
+  if (ctx->While()) {
     scope.enter();
-    if (ctx->For()) {
+    auto expr = ctx->expr(0);
-      visitValue(ctx->value(0));
+    auto type = std::any_cast<Type>(visitExpr(expr));
-    }
-    auto condition = ctx->condition();
-    auto type = std::any_cast<Type>(visitCondition(condition));
     if (type != Type::Boolean) {
-      errorlistener.typeMismatch(condition->getStart(), Type::Boolean, type);
+      errorlistener.typeMismatch(expr->getStart(), Type::Boolean, type);
     }
-    if (ctx->For()) {
+    loopcount++;
-      visitValue(ctx->value(1));
+    visitBlock(ctx->block(0));
+    loopcount--;
+    scope.leave();
+    return {};
+  }
+  if (ctx->For()) {
+    scope.enter();
+    visitExpr(ctx->expr(0));
+    auto expr = ctx->expr(1);
+    auto type = std::any_cast<Type>(visitExpr(expr));
+    if (type != Type::Boolean) {
+      errorlistener.typeMismatch(expr->getStart(), Type::Boolean, type);
     }
+    visitExpr(ctx->expr(2));
     loopcount++;
     visitBlock(ctx->block(0));
     loopcount--;
@@ -142,90 +149,153 @@ std::any TypeCheckVisitor::visitStatement(xlangParser::StatementContext *ctx) {
     return {};
   }
   if (ctx->Return()) {
-    auto type = std::any_cast<Type>(visitValue(ctx->value(0)));
+    auto type = std::any_cast<Type>(visitExpr(ctx->expr(0)));
-
     if (type != returntype) {
-      errorlistener.typeMismatch(ctx->value(0)->getStart(), returntype, type);
+      errorlistener.typeMismatch(ctx->expr(0)->getStart(), returntype, type);
     }
+    return {};
   }
   visitChildren(ctx);
   return {};
 }
 
-std::any TypeCheckVisitor::visitValue(xlangParser::ValueContext *ctx) {
+std::any TypeCheckVisitor::visitExpr(xlangParser::ExprContext *ctx) {
-  if (auto expr = ctx->expr()) {
+  if (auto op = ctx->assignmentOp()) {
-    return visitExpr(expr);
+    auto token = ctx->Identifier()->getSymbol();
+    auto name = token->getText();
+    if (op->Define()) {
+      auto type = std::any_cast<Type>(visitExpr(ctx->expr()));
+      if (scope.get(name)) {
+        errorlistener.shadowedVariable(token, name);
+      }
+      scope.add(name, type);
+      return type;
+    }
+    if (op->Assign()) {
+      auto type = std::any_cast<Type>(visitExpr(ctx->expr()));
+      if (auto expected = scope.get(name)) {
+        if (type != *expected) {
+          errorlistener.typeMismatch(token, *expected, type);
+        }
+        return *expected;
+      } else {
+        errorlistener.unknownVariable(token, name);
+        return type;
+      }
+    }
+    if (op->Increment() || op->Decrement()) {
+      if (auto type = scope.get(name)) {
+        if (*type != Type::Integer) {
+          errorlistener.typeMismatch(token, Type::Integer, *type);
+        }
+      } else {
+        errorlistener.unknownVariable(token, name);
+      }
+      auto expr = ctx->expr();
+      auto type = std::any_cast<Type>(visitExpr(expr));
+      if (type != Type::Integer) {
+        errorlistener.typeMismatch(expr->getStart(), Type::Integer, type);
+      }
+      return Type::Integer;
+    }
   }
-  if (auto condition = ctx->condition()) {
+  if (auto boolean_expr = ctx->booleanExpr()) {
-    return visitCondition(condition);
+    return visitBooleanExpr(boolean_expr);
   }
   // unreachable
   errorlistener.compilerError(__FILE__, __LINE__);
 }
 
-#define CHECKOPERATOR(visitLeft, left, visitRight, right, expected)     \
+std::any TypeCheckVisitor::visitBooleanExpr(
-  auto lefttype = std::any_cast<Type>(visitLeft(left));                 \
+    xlangParser::BooleanExprContext *ctx) {
-  auto righttype = std::any_cast<Type>(visitRight(right));              \
+  if (ctx->booleanOp().size()) {
-                                                                        \
+    for (auto comparison_expr : ctx->comparisonExpr()) {
-  if (lefttype != expected) {                                           \
+      auto type = std::any_cast<Type>(visitComparisonExpr(comparison_expr));
-    errorlistener.typeMismatch(left->getStart(), expected, lefttype);   \
+      if (type != Type::Boolean) {
-  }                                                                     \
+        errorlistener.typeMismatch(comparison_expr->getStart(), Type::Boolean,
-  if (righttype != expected) {                                          \
+                                   type);
-    errorlistener.typeMismatch(right->getStart(), expected, righttype); \
+      }
-  }
+    }
-
-std::any TypeCheckVisitor::visitCondition(xlangParser::ConditionContext *ctx) {
-  if (auto condition = ctx->condition()) {
-    CHECKOPERATOR(visitCondition, condition, visitBoolean, ctx->boolean(),
-                  Type::Boolean);
     return Type::Boolean;
   }
-  return visitBoolean(ctx->boolean());
+  if (auto comparison_expr = ctx->comparisonExpr(0)) {
+    return visitComparisonExpr(comparison_expr);
+  }
+  // unreachable
+  errorlistener.compilerError(__FILE__, __LINE__);
 }
 
-std::any TypeCheckVisitor::visitBoolean(xlangParser::BooleanContext *ctx) {
+std::any TypeCheckVisitor::visitComparisonExpr(
-  if (auto boolean = ctx->boolean()) {
+    xlangParser::ComparisonExprContext *ctx) {
-    auto type = std::any_cast<Type>(visitBoolean(boolean));
+  if (auto comparison_expr = ctx->comparisonExpr()) {
-
+    auto type = std::any_cast<Type>(visitComparisonExpr(comparison_expr));
     if (type != Type::Boolean) {
-      errorlistener.typeMismatch(boolean->getStart(), Type::Boolean, type);
+      errorlistener.typeMismatch(comparison_expr->getStart(), Type::Boolean,
+                                 type);
     }
     return Type::Boolean;
   }
   if (ctx->True() || ctx->False()) {
     return Type::Boolean;
   }
-  if (ctx->expr().size()) {
+  if (ctx->comparisonOp()) {
-    CHECKOPERATOR(visitExpr, ctx->expr(0), visitExpr, ctx->expr(1),
+    for (auto additive_expr : ctx->additiveExpr()) {
-                  Type::Integer);
+      auto type = std::any_cast<Type>(visitAdditiveExpr(additive_expr));
+      if (type != Type::Integer) {
+        errorlistener.typeMismatch(additive_expr->getStart(), Type::Integer,
+                                   type);
+      }
+    }
     return Type::Boolean;
   }
-  if (auto variable = ctx->variable()) {
+  if (auto additive_expr = ctx->additiveExpr(0)) {
-    return visitVariable(variable);
+    return visitAdditiveExpr(additive_expr);
   }
-  return visitCondition(ctx->condition());
+  // unreachable
+  errorlistener.compilerError(__FILE__, __LINE__);
 }
 
-std::any TypeCheckVisitor::visitExpr(xlangParser::ExprContext *ctx) {
+std::any TypeCheckVisitor::visitAdditiveExpr(
-  if (auto expr = ctx->expr()) {
+    xlangParser::AdditiveExprContext *ctx) {
-    CHECKOPERATOR(visitExpr, expr, visitTerm, ctx->term(), Type::Integer);
+  if (ctx->additiveOp().size()) {
+    for (auto multiplicative_expr : ctx->multiplicativeExpr()) {
+      auto type =
+          std::any_cast<Type>(visitMultiplicativeExpr(multiplicative_expr));
+      if (type != Type::Integer) {
+        errorlistener.typeMismatch(multiplicative_expr->getStart(),
+                                   Type::Integer, type);
+      }
+    }
     return Type::Integer;
   }
-  return visitTerm(ctx->term());
+  if (auto multiplicative_expr = ctx->multiplicativeExpr(0)) {
+    return visitMultiplicativeExpr(multiplicative_expr);
+  }
+  // unreachable
+  errorlistener.compilerError(__FILE__, __LINE__);
 }
 
-std::any TypeCheckVisitor::visitTerm(xlangParser::TermContext *ctx) {
+std::any TypeCheckVisitor::visitMultiplicativeExpr(
-  if (auto term = ctx->term()) {
+    xlangParser::MultiplicativeExprContext *ctx) {
-    CHECKOPERATOR(visitTerm, term, visitFactor, ctx->factor(), Type::Integer);
+  if (ctx->multiplicativeOp().size()) {
+    for (auto factor : ctx->factor()) {
+      auto type = std::any_cast<Type>(visitFactor(factor));
+      if (type != Type::Integer) {
+        errorlistener.typeMismatch(factor->getStart(), Type::Integer, type);
+      }
+    }
     return Type::Integer;
   }
-  return visitFactor(ctx->factor());
+  if (auto factor = ctx->factor(0)) {
+    return visitFactor(factor);
+  }
+  // unreachable
+  errorlistener.compilerError(__FILE__, __LINE__);
 }
 
 std::any TypeCheckVisitor::visitFactor(xlangParser::FactorContext *ctx) {
   if (auto factor = ctx->factor()) {
     auto type = std::any_cast<Type>(visitFactor(factor));
-
     if (type != Type::Integer) {
       errorlistener.typeMismatch(factor->getStart(), Type::Integer, type);
     }
@@ -234,92 +304,50 @@ std::any TypeCheckVisitor::visitFactor(xlangParser::FactorContext *ctx) {
   if (ctx->Integer()) {
     return Type::Integer;
   }
-  if (auto variable = ctx->variable()) {
+  if (auto identifier = ctx->Identifier()) {
-    return visitVariable(variable);
+    auto token = identifier->getSymbol();
-  }
+    auto name = token->getText();
-  return visitExpr(ctx->expr());
+    if (ctx->LeftParen()) {
-}
+      auto it = signatures.find(name);
-
+      if (it == signatures.end()) {
-std::any TypeCheckVisitor::visitVariable(xlangParser::VariableContext *ctx) {
+        errorlistener.unknownFunction(token, name);
-  auto token = ctx->Identifier()->getSymbol();
+        return Type::Invalid;
-  auto name = token->getText();
+      } else {
-
+        auto signature = it->second;
-  if (ctx->Define()) {
+        auto arity = signature.parametertypes.size();
-    auto type = std::any_cast<Type>(visitValue(ctx->value()));
+        if (auto arg_list = ctx->argumentList()) {
-
+          auto arg_num = arg_list->expr().size();
-    if (scope.get(name)) {
+          if (arity != arg_num) {
-      errorlistener.shadowedVariable(token, name);
+            errorlistener.wrongArgumentNumber(token, name, arity, arg_num);
-    }
+          }
-    scope.add(name, type);
+          for (size_t i = 0; i < arg_num && i < arity; i++) {
-    return type;
+            auto expr = arg_list->expr(i);
-  }
+            auto type = std::any_cast<Type>(visitExpr(expr));
-  if (ctx->Assign()) {
+            if (type != signature.parametertypes[i]) {
-    auto type = std::any_cast<Type>(visitValue(ctx->value()));
+              errorlistener.typeMismatch(expr->getStart(),
-
+                                         signature.parametertypes[i], type);
-    if (auto expected = scope.get(name)) {
+            }
-      if (type != *expected) {
+          }
-        errorlistener.typeMismatch(token, *expected, type);
+        } else {
+          if (arity) {
+            errorlistener.wrongArgumentNumber(token, name, arity, 0);
+          }
+        }
+        return signature.returntype;
       }
-      return *expected;
+    }
+    if (auto type = scope.get(name)) {
+      return *type;
     } else {
       errorlistener.unknownVariable(token, name);
-      return type;
+      return Type::Invalid;
     }
   }
   if (auto expr = ctx->expr()) {
-    auto righttype = std::any_cast<Type>(visitExpr(expr));
+    return visitExpr(expr);
-
-    if (auto lefttype = scope.get(name)) {
-      if (*lefttype != Type::Integer) {
-        errorlistener.typeMismatch(token, Type::Integer, *lefttype);
-      }
-    } else {
-      errorlistener.unknownVariable(token, name);
-    }
-    if (righttype != Type::Integer) {
-      errorlistener.typeMismatch(token, Type::Integer, righttype);
-    }
-    return Type::Integer;
-  }
-  if (ctx->LeftParen()) {
-    auto it = signatures.find(name);
-
-    if (it == signatures.end()) {
-      errorlistener.unknownFunction(token, name);
-      return Type::Invalid;
-    } else {
-      auto signature = it->second;
-      auto arity = signature.parametertypes.size();
-
-      if (auto arg_list = ctx->argumentList()) {
-        auto arg_num = arg_list->value().size();
-
-        if (arity != arg_num) {
-          errorlistener.wrongArgumentNumber(token, name, arity, arg_num);
-        }
-        for (size_t i = 0; i < arg_num && i < arity; i++) {
-          auto type = std::any_cast<Type>(visitValue(arg_list->value(i)));
-          auto token = arg_list->value(i)->getStart();
-
-          if (type != signature.parametertypes[i]) {
-            errorlistener.typeMismatch(token, signature.parametertypes[i],
-                                       type);
-          }
-        }
-      } else {
-        if (arity) {
-          errorlistener.wrongArgumentNumber(token, name, arity, 0);
-        }
-      }
-      return signature.returntype;
-    }
-  }
-  if (auto type = scope.get(name)) {
-    return *type;
-  } else {
-    errorlistener.unknownVariable(token, name);
-    return Type::Invalid;
   }
+  // unreachable
+  errorlistener.compilerError(__FILE__, __LINE__);
 }
 
 }  // namespace xlang

bootstrap/typecheck.hh

@@ -39,13 +39,14 @@ class TypeCheckVisitor : public xlangBaseVisitor {
   std::any visitType(xlangParser::TypeContext *ctx) override;
   std::any visitBlock(xlangParser::BlockContext *ctx) override;
   std::any visitStatement(xlangParser::StatementContext *ctx) override;
-  std::any visitValue(xlangParser::ValueContext *ctx) override;
-  std::any visitCondition(xlangParser::ConditionContext *ctx) override;
-  std::any visitBoolean(xlangParser::BooleanContext *ctx) override;
   std::any visitExpr(xlangParser::ExprContext *ctx) override;
-  std::any visitTerm(xlangParser::TermContext *ctx) override;
+  std::any visitBooleanExpr(xlangParser::BooleanExprContext *ctx) override;
+  std::any visitComparisonExpr(
+      xlangParser::ComparisonExprContext *ctx) override;
+  std::any visitAdditiveExpr(xlangParser::AdditiveExprContext *ctx) override;
+  std::any visitMultiplicativeExpr(
+      xlangParser::MultiplicativeExprContext *ctx) override;
   std::any visitFactor(xlangParser::FactorContext *ctx) override;
-  std::any visitVariable(xlangParser::VariableContext *ctx) override;
 };
 
 }  // namespace xlang

bootstrap/xlang.g4

@@ -2,53 +2,45 @@ grammar xlang;
 
 file  : function+ EOF;
 function  : Identifier LeftParen parameterList? RightParen Colon type block;
-parameterList  : Identifier Colon type (Comma Identifier Colon type)*;
+parameterList  : parameter (Comma parameter)*;
+parameter : Identifier Colon type;
 type  : TypeInteger
       | TypeBoolean
       ;
 block : LeftBrace statement* RightBrace;
-statement : If condition block (Else block)?
+statement : If expr block (Else block)?
-          | While condition block
+          | While expr block
-          | For value Semicolon condition Semicolon value block
+          | For expr Semicolon expr Semicolon expr block
           | Break Integer? Semicolon
           | Continue Integer? Semicolon
-          | Return value Semicolon
+          | Return expr Semicolon
-          | Print value Semicolon
+          | Print expr Semicolon
-          | value Semicolon
+          | expr Semicolon
           ;
-value : expr
+expr  : Identifier assignmentOp expr 
-      | condition
+      | booleanExpr
-      ;
-condition : condition (And|Or|Xor) boolean
-          | boolean
-          ;
-boolean : Not boolean
-        | True
-        | False
-        | expr (Less|LessEqual|Greater|GreaterEqual|Equal|NotEqual) expr
-        | variable
-        | LeftParen condition RightParen
-        ;
-expr  : expr (Plus|Minus|BitAnd|BitOr|BitXor|ShiftLeft|ShiftRight) term
-      | term
-      ;
-term  : term (Mul|Div|Rem) factor
-      | factor
       ;
+assignmentOp : Define | Assign | Increment | Decrement;
+booleanExpr : comparisonExpr (booleanOp comparisonExpr)*;
+booleanOp  : And | Or | Xor;
+comparisonExpr : Not comparisonExpr
+                | True
+                | False
+                | additiveExpr (comparisonOp additiveExpr)?
+                ;
+comparisonOp : Less | LessEqual | Greater | GreaterEqual | Equal | NotEqual;
+additiveExpr  : multiplicativeExpr (additiveOp multiplicativeExpr)*;
+additiveOp : Plus | Minus | BitAnd | BitOr | BitXor | ShiftLeft | ShiftRight;
+multiplicativeExpr  : factor (multiplicativeOp factor)*;
+multiplicativeOp : Mul | Div | Rem;
 factor  : Minus factor
         | BitNot factor
         | Integer
-        | variable
+        | Identifier
+        | Identifier LeftParen argumentList? RightParen
         | LeftParen expr RightParen
         ;
-variable  : Identifier
+argumentList  : expr (Comma expr)*;
-          | Identifier Define value
-          | Identifier Assign value
-          | Identifier Increment expr
-          | Identifier Decrement expr
-          | Identifier LeftParen argumentList? RightParen
-          ;
-argumentList  : value (Comma value)*;
 
 TypeInteger : 'int';
 TypeBoolean : 'bool';