make definitions/assignments expressions

bootstrap/emit.cc

@@ -34,13 +34,6 @@ std::any EmitVisitor::visitFunction(xlangParser::FunctionContext *ctx) {
 }
 
 std::any EmitVisitor::visitStatement(xlangParser::StatementContext *ctx) {
-  if (auto identifier = ctx->Identifier()) {
-    tmpcount = 0;
-    visitValue(ctx->value());
-    output << "  %_" << identifier->getSymbol()->getText() << " = w copy "
-           << last << std::endl;
-    return {};
-  }
   if (ctx->If()) {
     int block = blockcount++;
 
@@ -78,10 +71,12 @@ std::any EmitVisitor::visitStatement(xlangParser::StatementContext *ctx) {
   if (ctx->Break()) {
     output << "  jmp @while" << loopstack.back() << "_end" << std::endl;
     output << "@dead" << blockcount++ << std::endl;
+    return {};
   }
   if (ctx->Continue()) {
     output << "  jmp @while" << loopstack.back() << "_expr" << std::endl;
     output << "@dead" << blockcount++ << std::endl;
+    return {};
   }
   if (ctx->Return()) {
     tmpcount = 0;
@@ -97,7 +92,7 @@ std::any EmitVisitor::visitStatement(xlangParser::StatementContext *ctx) {
            << std::endl;
     return {};
   }
-  // unreachable
+  visitValue(ctx->value());
   return {};
 }
 
@@ -189,6 +184,12 @@ std::any EmitVisitor::visitFactor(xlangParser::FactorContext *ctx) {
 std::any EmitVisitor::visitVariable(xlangParser::VariableContext *ctx) {
   auto name = ctx->Identifier()->getSymbol()->getText();
 
+  if (ctx->Define() || ctx->Assign()) {
+    visitValue(ctx->value());
+    output << "  %_" << name << " = w copy " << last << std::endl;
+    last = "%_" + name;
+    return {};
+  }
   if (ctx->LeftParen()) {
     std::vector<std::string> args;
 
@@ -203,9 +204,9 @@ std::any EmitVisitor::visitVariable(xlangParser::VariableContext *ctx) {
       output << "w " << arg << ", ";
     }
     output << ")" << std::endl;
-  } else {
+    return {};
-    last = "%_" + name;
   }
+  last = "%_" + name;
   return {};
 }
 

bootstrap/typecheck.cc

@@ -9,9 +9,11 @@ std::string typeToString(Type type) {
       return "int";
     case Type::Boolean:
       return "bool";
-  }
+    default:
+    case Type::Invalid:
       return "<invalid>";
   }
+}
 
 TypeCheckVisitor::TypeCheckVisitor(ErrorListener &errorlistener)
     : errorlistener{errorlistener}, loopcount{0} {}
@@ -73,30 +75,6 @@ std::any TypeCheckVisitor::visitBlock(xlangParser::BlockContext *ctx) {
 }
 
 std::any TypeCheckVisitor::visitStatement(xlangParser::StatementContext *ctx) {
-  if (auto identifier = ctx->Identifier()) {
-    auto name = identifier->getSymbol()->getText();
-    auto type = std::any_cast<Type>(visitValue(ctx->value()));
-
-    if (ctx->Define()) {
-      if (scope.get(name)) {
-        errorlistener.shadowedVariable(identifier->getSymbol(), name);
-      }
-      scope.add(name, type);
-      return {};
-    }
-    if (ctx->Assign()) {
-      if (auto expected = scope.get(name)) {
-        if (type != *expected) {
-          errorlistener.typeMismatch(identifier->getSymbol(), *expected, type);
-        }
-      } else {
-        errorlistener.unknownVariable(identifier->getSymbol(), name);
-      }
-      return {};
-    }
-    // unreachable
-    errorlistener.compilerError(__FILE__, __LINE__);
-  }
   if (auto condition = ctx->condition()) {
     auto type = std::any_cast<Type>(visitCondition(condition));
 
@@ -230,12 +208,34 @@ std::any TypeCheckVisitor::visitVariable(xlangParser::VariableContext *ctx) {
   auto token = ctx->Identifier()->getSymbol();
   auto name = token->getText();
 
+  if (ctx->Define()) {
+    auto type = std::any_cast<Type>(visitValue(ctx->value()));
+
+    if (scope.get(name)) {
+      errorlistener.shadowedVariable(token, name);
+    }
+    scope.add(name, type);
+    return type;
+  }
+  if (ctx->Assign()) {
+    auto type = std::any_cast<Type>(visitValue(ctx->value()));
+
+    if (auto expected = scope.get(name)) {
+      if (type != *expected) {
+        errorlistener.typeMismatch(token, *expected, type);
+      }
+      return *expected;
+    } else {
+      errorlistener.unknownVariable(token, name);
+      return type;
+    }
+  }
   if (ctx->LeftParen()) {
     auto it = signatures.find(name);
 
     if (it == signatures.end()) {
       errorlistener.unknownFunction(token, name);
-      return Type::Integer;
+      return Type::Invalid;
     } else {
       auto signature = it->second;
       auto arity = signature.parametertypes.size();
@@ -262,16 +262,13 @@ std::any TypeCheckVisitor::visitVariable(xlangParser::VariableContext *ctx) {
       }
       return signature.returntype;
     }
-  } else {
-    auto type = scope.get(name);
-    if (!type) {
-      errorlistener.unknownVariable(token, name);
-      return Type::Integer;
   }
+  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

@@ -12,6 +12,7 @@ class ErrorListener;
 
 enum class Type
 {
+  Invalid,
   Integer,
   Boolean,
 };

bootstrap/xlang.g4

@@ -7,14 +7,13 @@ type  : TypeInteger
       | TypeBoolean
       ;
 block : LeftBrace statement* RightBrace;
-statement : Identifier Define value Semicolon
+statement : If condition block (Else block)?
-          | Identifier Assign value Semicolon
-          | If condition block (Else block)?
           | While condition block
           | Break Semicolon
           | Continue Semicolon
           | Return value Semicolon
           | Print value Semicolon
+          | value Semicolon
           ;
 value : expr
       | condition
@@ -42,6 +41,8 @@ factor  : Minus factor
         | LeftParen expr RightParen
         ;
 variable  : Identifier
+          | Identifier Define value
+          | Identifier Assign value
           | Identifier LeftParen argumentList? RightParen
           ;
 argumentList  : value (Comma value)*;