public void VisitNode(AbstractNode node)
{
VisitChildren(node);
}
private void VisitNode(MethodCall node)
{
AbstractNode methodReference = node.Child;
AbstractNode argumentList = methodReference.Sib; // may be null
TypeDescriptor descriptor;
QualifiedName qualifiedName = methodReference as QualifiedName;
if (qualifiedName == null)
{
descriptor = new ErrorDescriptor
("Only Qualified Name supported for Method Call reference");
}
else
{
// get parameters from method call
List <TypeDescriptor> argListTypes =
GetParameterTypes(argumentList as ArgumentList);
// get parameters (signature) from declared method
Attributes attr = Table.lookup(qualifiedName.GetStringName());
MethodTypeDescriptor methodDescriptor =
attr.TypeDescriptor as MethodTypeDescriptor;
if (methodDescriptor != null)
{
SignatureDescriptor methodSignature = methodDescriptor.Signature;
if (methodSignature != null &&
ParametersMatch(methodSignature, argListTypes))
{
// method descriptor for only current signature
MethodTypeDescriptor temp = new MethodTypeDescriptor();
temp.ReturnType = methodDescriptor.ReturnType;
temp.Signature.ParameterTypes = argListTypes;
temp.Signature.Next = null;
descriptor = temp;
}
else if (methodSignature == null)
{
descriptor = new ErrorDescriptor
("No signature found for method: " +
qualifiedName.GetStringName());
}
else
{
descriptor = new ErrorDescriptor
("No method signature found matching: (" +
String.Join(", ", argListTypes) + ")");
}
}
else
{
descriptor = new ErrorDescriptor("Method not declared: " +
qualifiedName.GetStringName());
}
node.TypeDescriptor = descriptor;
Attributes methodCallAttr = new Attr(descriptor);
methodCallAttr.Kind = Kind.MethodType;
node.AttributesRef = methodCallAttr;
}
}
private void VisitNode(SelectionStatement node)
{
AbstractNode ifExp = node.Child;
AbstractNode thanStmt = ifExp.Sib;
AbstractNode elseStmt = thanStmt.Sib; // may be null
SelectionStatementDescriptor ssDesc =
new SelectionStatementDescriptor();
String errMsg = "";
// if expression
ifExp.Accept(this);
ssDesc.IfDescriptor = ifExp.TypeDescriptor;
PrimitiveTypeBooleanDescriptor ifBoolDesc =
ifExp.TypeDescriptor as PrimitiveTypeBooleanDescriptor;
if (ifBoolDesc == null)
{
ifExp.TypeDescriptor = new ErrorDescriptor("If statement " +
"does not evaluate to a Boolean expression. (Has type: " +
ifExp.TypeDescriptor.GetType().Name + ")");
}
// than statement
thanStmt.Accept(this);
thanStmt.TypeDescriptor = thanStmt.Child.TypeDescriptor;
ssDesc.ThanDescriptor = thanStmt.TypeDescriptor;
if (!IsCompatibleStatement(thanStmt.TypeDescriptor))
{
if (errMsg.Length > 0)
{
errMsg += "\n";
}
errMsg += "Non-compatible THAN statement type: " +
thanStmt.TypeDescriptor.GetType().Name;
}
// else statement
if (elseStmt != null)
{
elseStmt.Accept(this);
ssDesc.HasElseStmt = true;
elseStmt.TypeDescriptor = elseStmt.Child.TypeDescriptor;
ssDesc.ElseDescriptor = elseStmt.TypeDescriptor;
if (!IsCompatibleStatement(elseStmt.TypeDescriptor))
{
if (errMsg.Length > 0)
{
errMsg += "\n";
}
errMsg += "Non-compatible ELSE statement type: " +
elseStmt.TypeDescriptor.GetType().Name;
}
}
else
{
ssDesc.HasElseStmt = false;
}
// if any components have errors, propogate them up the tree
if (ifExp.TypeDescriptor is ErrorDescriptor ||
thanStmt.TypeDescriptor is ErrorDescriptor ||
elseStmt?.TypeDescriptor is ErrorDescriptor)
{
// creates an error containing any and all errors lower in tree
if (ifExp.TypeDescriptor is ErrorDescriptor)
{
ssDesc.TypeDescriptor = ifExp.TypeDescriptor;
if (thanStmt.TypeDescriptor is ErrorDescriptor)
{
((ErrorDescriptor)ssDesc.TypeDescriptor).CombineErrors
((ErrorDescriptor)thanStmt.TypeDescriptor);
}
if (elseStmt?.TypeDescriptor is ErrorDescriptor)
{
((ErrorDescriptor)ssDesc.TypeDescriptor).CombineErrors
((ErrorDescriptor)elseStmt.TypeDescriptor);
}
}
else if (thanStmt.TypeDescriptor is ErrorDescriptor)
{
ssDesc.TypeDescriptor = thanStmt.TypeDescriptor;
if (elseStmt?.TypeDescriptor is ErrorDescriptor)
{
((ErrorDescriptor)ssDesc.TypeDescriptor).CombineErrors
((ErrorDescriptor)elseStmt.TypeDescriptor);
}
}
else
{
ssDesc.TypeDescriptor = elseStmt.TypeDescriptor;
}
}
// if IF/THAN/ELSE was incompatible, create new error
else if (errMsg.Length > 0)
{
ssDesc.TypeDescriptor = new ErrorDescriptor(errMsg);
}
// otherwise assign evaluated boolean to selection statement desc
else
{
ssDesc.TypeDescriptor = ifExp.TypeDescriptor;
}
node.TypeDescriptor = ssDesc;
}
private TypeDescriptor AssignmentExp(AbstractNode qualName, AbstractNode exp)
{
QualifiedName name = qualName as QualifiedName;
Expression expression = exp as Expression;
PrimaryExpression primaryExp = exp as PrimaryExpression;
TypeDescriptor nameDesc;
if (name != null && (expression != null || primaryExp != null))
{
Attributes nameAttr = Table.lookup(name.GetStringName());
qualName.AttributesRef = nameAttr;
qualName.TypeDescriptor = nameAttr.TypeDescriptor;
exp.Accept(this);
// Check for errors
// if both types are Error Descriptors, combine errors
ErrorDescriptor nameErrDesc =
nameAttr.TypeDescriptor as ErrorDescriptor;
ErrorDescriptor expErrDesc =
exp.TypeDescriptor as ErrorDescriptor;
if (nameErrDesc != null && expErrDesc != null)
{
nameDesc = nameErrDesc.CombineErrors(expErrDesc);
}
// if one or the other is an error, propagate the error up
else if (nameErrDesc != null)
{
nameDesc = nameAttr.TypeDescriptor;
}
else if (expErrDesc != null)
{
nameDesc = exp.TypeDescriptor;
}
// check that the variable being assigned to is assignable
else if (nameAttr.IsAssignable)
{
// if types compatible, assign successfully assigned type
if (TypesCompatible(nameAttr.TypeDescriptor,
exp.TypeDescriptor))
{
nameDesc = GetAssignmentDesc(nameAttr.TypeDescriptor,
exp.TypeDescriptor);
}
// otherwise, assign new error for incompatible types
else
{
nameDesc = new ErrorDescriptor("Incompatible types: " +
"cannot assign " + GetSimpleName(exp.TypeDescriptor)
+ " to " + GetSimpleName(nameAttr.TypeDescriptor) +
" variable");
}
}
// variable is not assignable
else
{
nameDesc = new ErrorDescriptor(nameAttr +
" is not assigable. Cannot assign as " +
GetSimpleName(exp.TypeDescriptor));
}
}
// Assignment not made up of correct parts
else
{
string message = "";
if (name == null && expression == null)
{
message += "EQUALS expression expects 'QualifiedName' " +
"on LHS, but has: " + qualName.GetType().Name +
" & 'Expression' or 'PrimaryExression' on " +
"RHS, but has " + exp.GetType().Name;
}
else if (name == null)
{
message += "EQUALS expression expects 'QualifiedName' on" +
" LHS, but has: " + qualName.GetType().Name;
}
else
{
message += "EQUALS expression expects 'Expression' or " +
"'PrimaryExpression' on RHS, but has: " +
exp.GetType().Name;
}
nameDesc = new ErrorDescriptor(message);
}
return(nameDesc);
}
public void CreateIlFileContent(AbstractNode node)
{
node?.Accept(this);
}
private string GetIlType(AbstractNode node)
{
return(GetIlType(node.TypeDescriptor, node));
}
private string GetIlTypeParam(AbstractNode node)
{
AbstractNode typeSpecifier = node.Child;
return($"{GetIlType(typeSpecifier)}");
}
private new void VisitNode(AbstractNode node)
{
VisitChildren(node);
}
private void VisitNode(MethodDeclaration node)
{
AbstractNode modifiers = node.Child;
AbstractNode typeSpecifier = modifiers.Sib;
AbstractNode methodDeclarator = typeSpecifier.Sib;
AbstractNode methodBody = methodDeclarator.Sib;
AbstractNode retType = typeSpecifier.Child;
if (retType is PrimitiveTypeVoid)
{
((PrimitiveTypeVoid)retType).Accept(TypeVisitor);
}
else if (retType is PrimitiveTypeBoolean)
{
((PrimitiveTypeBoolean)retType).Accept(TypeVisitor);
}
else if (retType is PrimitiveTypeInt)
{
((PrimitiveTypeInt)retType).Accept(TypeVisitor);
}
else if (retType is QualifiedName)
{
((QualifiedName)retType).Accept(TypeVisitor);
}
else
{
string msg = "Return type of a method must be a " +
"PrimitiveType or QualifiedName (found: " +
GetSimpleName(retType.TypeDescriptor);
retType.TypeDescriptor = new ErrorDescriptor(msg);
}
AbstractNode methodDeclaratorName = methodDeclarator.Child;
AbstractNode parameterList = methodDeclaratorName.Sib; // may be null
MethodTypeDescriptor methDesc = new MethodTypeDescriptor();
methDesc.ReturnType = retType.TypeDescriptor;
methDesc.Modifiers = ((Modifiers)modifiers).ModifierTokens;
methDesc.Locals = new ScopeTable();
methDesc.IsDefinedIn = CurrentClass;
Attributes attr = new Attr(methDesc);
attr.Kind = Kind.MethodType;
string name = ((Identifier)methodDeclaratorName).ID;
Table.enter(name, attr);
node.TypeDescriptor = attr.TypeDescriptor;
node.AttributesRef = attr;
Table.openScope(methDesc.Locals);
MethodTypeDescriptor oldCurrentMethod = CurrentMethod;
CurrentMethod = methDesc;
if (parameterList != null)
{
parameterList.Accept(this);
methDesc.Signature.ParameterTypes =
((ParameterListTypeDescriptor)
parameterList.TypeDescriptor).ParamTypeDescriptors;
attr.TypeDescriptor = methDesc;
Table.updateValue(name, attr);
node.TypeDescriptor = methDesc;
node.AttributesRef = Table.lookup(name);
}
methodBody.Accept(this);
CurrentMethod = oldCurrentMethod;
Table.closeScope();
}
