private TypeDescriptor GetAssignmentDesc(TypeDescriptor name,
TypeDescriptor exp)
{
// assign integer value
int valueInt = 0; // TODO: setting to 0 is not a good solution
// fails if type check is not accurate
NumberTypeDescriptor expNum = exp as NumberTypeDescriptor;
PrimitiveTypeIntDescriptor expInt = exp as PrimitiveTypeIntDescriptor;
if (expNum != null || expInt != null)
{
if (expNum != null)
{
valueInt = expNum.Num;
}
if (expInt != null)
{
valueInt = expInt.Value;
}
NumberTypeDescriptor nameNum = name as NumberTypeDescriptor;
PrimitiveTypeIntDescriptor nameInt = name as PrimitiveTypeIntDescriptor;
if (nameNum != null)
{
nameNum.Num = valueInt;
return(nameNum);
}
if (nameInt != null)
{
nameInt.Value = valueInt;
return(nameInt);
}
}
// assign bool value
PrimitiveTypeBooleanDescriptor expBoolean = exp as PrimitiveTypeBooleanDescriptor;
PrimitiveTypeBooleanDescriptor nameBoolean = name as PrimitiveTypeBooleanDescriptor;
if (expBoolean != null && nameBoolean != null)
{
nameBoolean.Value = expBoolean.Value;
return(nameBoolean);
}
// assign string value
LiteralTypeDescriptor expLiteral = exp as LiteralTypeDescriptor;
LiteralTypeDescriptor nameLiteral = name as LiteralTypeDescriptor;
if (expLiteral != null && nameLiteral != null)
{
nameLiteral.Value = expLiteral.Value;
return(nameLiteral);
}
// assign an error if value unassignable
return(new ErrorDescriptor("Assignment of value from " +
exp.GetType().Name + " to " + name.GetType().Name + " failed"));
}
private string GetIlType(TypeDescriptor desc, AbstractNode typeSpec)
{
// either the return type is a primitive (can get from the signature)
PrimitiveTypeIntDescriptor intDesc =
desc as PrimitiveTypeIntDescriptor;
NumberTypeDescriptor numDesc = desc as NumberTypeDescriptor;
if (intDesc != null || numDesc != null)
{
return("int32");
}
PrimitiveTypeStringDescriptor stringDesc =
desc as PrimitiveTypeStringDescriptor;
LiteralTypeDescriptor litDesc = desc as LiteralTypeDescriptor;
if (stringDesc != null || litDesc != null)
{
return("string");
}
PrimitiveTypeBooleanDescriptor boolDesc =
desc as PrimitiveTypeBooleanDescriptor;
if (boolDesc != null)
{
return("bool");
}
PrimitiveTypeVoidDescriptor voidDesc =
desc as PrimitiveTypeVoidDescriptor;
if (voidDesc != null)
{
return("void");
}
// or it is a qualified name (can extract from the node)
QualifiedName qName = typeSpec as QualifiedName;
if (qName != null)
{
return(qName.GetStringName());
}
// or it is an error
ErrorDescriptor err = desc as ErrorDescriptor;
if (err != null)
{
return(err.Message);
}
return("");
}
private void VisitNode(IterationStatement node)
{
AbstractNode whileExp = node.Child;
AbstractNode bodyStmt = whileExp.Sib;
IterationStatementDescriptor iterDesc =
new IterationStatementDescriptor();
// while expression
whileExp.Accept(this);
iterDesc.WhileDescriptor = whileExp.TypeDescriptor;
PrimitiveTypeBooleanDescriptor whileBoolDesc =
whileExp.TypeDescriptor as PrimitiveTypeBooleanDescriptor;
if (whileBoolDesc == null)
{
iterDesc.TypeDescriptor = new ErrorDescriptor("If statement " +
"does not evaluate to a Boolean expression. (Has type: " +
GetSimpleName(whileExp.TypeDescriptor) + ")");
}
// if body stmt empty, infinite loop error
bodyStmt.Accept(this);
bodyStmt.TypeDescriptor = bodyStmt.Child.TypeDescriptor;
iterDesc.BodyDescriptor = bodyStmt.TypeDescriptor;
// propagate up errors as needed
if (iterDesc.WhileDescriptor is ErrorDescriptor ||
iterDesc.BodyDescriptor is ErrorDescriptor)
{
if (iterDesc.WhileDescriptor is ErrorDescriptor)
{
iterDesc.TypeDescriptor = iterDesc.WhileDescriptor;
if (iterDesc.BodyDescriptor is ErrorDescriptor)
{
((ErrorDescriptor)iterDesc.TypeDescriptor).CombineErrors(
(ErrorDescriptor)iterDesc.BodyDescriptor);
}
}
else
{
iterDesc.TypeDescriptor = iterDesc.BodyDescriptor;
}
}
// otherwise assign appropriate iteration statement descriptor
else
{
iterDesc.TypeDescriptor = iterDesc.WhileDescriptor;
}
node.TypeDescriptor = iterDesc;
}
private string GetIlType(TypeDescriptor desc)
{
// either the return type is a primitive (can get from the signature)
PrimitiveTypeIntDescriptor intDesc =
desc as PrimitiveTypeIntDescriptor;
NumberTypeDescriptor numDesc = desc as NumberTypeDescriptor;
if (intDesc != null || numDesc != null)
{
return("int32");
}
PrimitiveTypeStringDescriptor stringDesc =
desc as PrimitiveTypeStringDescriptor;
LiteralTypeDescriptor litDesc = desc as LiteralTypeDescriptor;
if (stringDesc != null || litDesc != null)
{
return("string");
}
PrimitiveTypeBooleanDescriptor boolDesc =
desc as PrimitiveTypeBooleanDescriptor;
if (boolDesc != null)
{
return("bool");
}
PrimitiveTypeVoidDescriptor voidDesc =
desc as PrimitiveTypeVoidDescriptor;
if (voidDesc != null)
{
return("void");
}
// or it is an error
ErrorDescriptor err = desc as ErrorDescriptor;
if (err != null)
{
return(err.Message);
}
return("");
}
private void PrintValue(AbstractNode node)
{
if (node.TypeDescriptor != null)
{
Console.ForegroundColor = ConsoleColor.DarkMagenta;
NumberTypeDescriptor num =
node.TypeDescriptor as NumberTypeDescriptor;
if (num != null)
{
Console.Write(" " + num.Num);
return;
}
PrimitiveTypeIntDescriptor primInt =
node.TypeDescriptor as PrimitiveTypeIntDescriptor;
if (primInt != null)
{
Console.Write(" " + primInt.Value);
return;
}
PrimitiveTypeBooleanDescriptor primBool =
node.TypeDescriptor as PrimitiveTypeBooleanDescriptor;
if (primBool != null)
{
Console.Write(" " + primBool.Value);
return;
}
LiteralTypeDescriptor lit =
node.TypeDescriptor as LiteralTypeDescriptor;
if (lit != null)
{
Console.Write(" " + lit.Value);
return;
}
Console.ResetColor();
}
}
public PrimitiveTypeBoolean()
{
TypeDescriptor = new PrimitiveTypeBooleanDescriptor();
}
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;
}