private void CalculateTypeForNodes(IAstNode exprNode)
{
if (exprNode.AstNodeType == AstNodeTypes.BinaryOperator)
{
var binOpNode = exprNode.AsBinaryOp();
CalculateTypeForNodes(binOpNode.LeftOperand);
binOpNode.TypeName = binOpNode.LeftOperand.AsNodeWithType().TypeName;
CalculateTypeForNodes(binOpNode.RightOperand);
}
else if (exprNode.AstNodeType == AstNodeTypes.UnaryOperator)
{
CalculateTypeForNodes(exprNode.AsUnaryOp().Operand);
}
else if (exprNode.AstNodeType == AstNodeTypes.VarReference)
{
var varRef = exprNode.AsVarReferene();
if (!_symbolTable.ContainsKey(varRef.Name))
{
throw new SemanticErrorException($"Variable '{varRef.Name}' is not declared.", exprNode);
}
exprNode.AsVarReferene().TypeName = _symbolTable[varRef.Name];
}
}
private void CheckNodeType(IAstNode exprNode)
{
if (exprNode.AstNodeType == AstNodeTypes.BinaryOperator)
{
var binOpNode = exprNode.AsBinaryOp();
CheckNodeType(binOpNode.LeftOperand);
CheckNodeType(binOpNode.RightOperand);
if (binOpNode.LeftOperand.AsNodeWithType().TypeName !=
binOpNode.RightOperand.AsNodeWithType().TypeName)
{
throw new SemanticErrorException("Type mismatch.", binOpNode);
}
}
else if (exprNode.AstNodeType == AstNodeTypes.UnaryOperator)
{
var unaryOpNode = exprNode.AsUnaryOp();
CheckNodeType(unaryOpNode.Operand);
if (unaryOpNode.TypeName != unaryOpNode.Operand.AsNodeWithType().TypeName)
{
throw new SemanticErrorException("Type mismatch.", unaryOpNode);
}
}
}
public void Traverse(IAstNode astNode)
{
ProcessNode?.Invoke(astNode);
switch (astNode.AstNodeType)
{
case AstNodeTypes.VarStatement:
Traverse(astNode.AsVarStatement().Expression);
break;
case AstNodeTypes.PrintStatement:
foreach (var printExpr in astNode.AsPrintStatement().PrintExpressions)
{
Traverse(printExpr);
}
break;
case AstNodeTypes.PrintExpression:
Traverse(astNode.AsPrintExpression().Expression);
break;
case AstNodeTypes.UnaryOperator:
Traverse(astNode.AsUnaryOp().Operand);
break;
case AstNodeTypes.BinaryOperator:
Traverse(astNode.AsBinaryOp().LeftOperand);
Traverse(astNode.AsBinaryOp().RightOperand);
break;
case AstNodeTypes.NumberLiteral:
break;
case AstNodeTypes.StringLiteral:
break;
case AstNodeTypes.VarReference:
break;
}
PostProcessNode?.Invoke(astNode.AstNodeType);
}