public override List <string> ExecuteSemanticAction(Stack <SemanticRecord> semanticRecordTable, Stack <SymbolTable> symbolTable, IToken lastToken, MoonCodeResult moonCode)
{
SymbolTable currentTable = symbolTable.Peek();
List <string> errors = new List <string>();
string className = lastToken.getSemanticName();
// Check if the class' name already exists
foreach (Entry entry in currentTable.GetEntries())
{
if (entry.getName() == className)
{
errors.Add(string.Format("Identifier {0} at line {1} has already been declared", className, lastToken.getLine()));
break;
}
}
// Create a class entry
Entry classEntry = new ClassEntry(className, currentTable);
symbolTable.Push(classEntry.getChild());
return(errors);
}
public override List <string> ExecuteSemanticAction(Stack <SemanticRecord> semanticRecordTable, Stack <SymbolTable> symbolTable, IToken lastToken, MoonCodeResult moonCode)
{
Stack <SemanticRecord> callChain = new Stack <SemanticRecord>();
List <string> errors = new List <string>();
if (!semanticRecordTable.Any())
{
errors.Add(string.Format("Grammar error at line {0}: could not verify factor for emtpy stack", lastToken.getLine()));
return(errors);
}
SemanticRecord lastRecord = semanticRecordTable.Pop();
// Accumulate semantic records until we reach the start of the factor
while (lastRecord.recordType != RecordTypes.FactorStart)
{
callChain.Push(lastRecord);
if (!semanticRecordTable.Any())
{
errors.Add(string.Format("Grammar error at {0}. Could not find start for a factor", lastToken.getLine()));
break;
}
lastRecord = semanticRecordTable.Pop();
}
SemanticRecord currentLink = callChain.Pop();
Entry linkedVariable = null;
// The first element in the chain is a reference to a locally accessible variable or function
// Go through symbol tables of increasing scope until we find the referenced identifier
foreach (SymbolTable table in symbolTable)
{
linkedVariable = table.GetEntries().FirstOrDefault(x => (x is VarParamEntry || x is FunctionEntry) && x.getName() == currentLink.getValue());
if (linkedVariable != null)
{
break;
}
}
// Verify the validity of this initial reference
bool success = VerifyLink(currentLink, linkedVariable, lastToken, errors);
// Go through the call chain and verify each link
while (callChain.Any() && success)
{
currentLink = callChain.Pop();
ClassEntry referredClass = ((VarParamEntry)linkedVariable).getVariable().getClass();
if (referredClass.getChild() == null)
{
errors.Add(string.Format("Identifier {0} cannot be reached at line {1}", currentLink.getValue(), lastToken.getLine()));
return(errors);
}
// Look in the referred class for the variable or function that is being referred to
linkedVariable = referredClass.getChild().GetEntries().FirstOrDefault(x => (x is VarParamEntry || x is FunctionEntry) && x.getName() == currentLink.getValue());
success = VerifyLink(currentLink, linkedVariable, lastToken, errors);
}
ClassEntry expressionType = new ClassEntry("undefined", 0);
// Find the linked variable and create a new expression for it
if (linkedVariable is VarParamEntry)
{
expressionType = ((VarParamEntry)linkedVariable).getVariable().getClass();
}
else if (linkedVariable is FunctionEntry)
{
expressionType = ((FunctionEntry)linkedVariable).GetReturnType();
}
if (linkedVariable == null)
{
errors.Add(string.Format("Grammar error: Could not link variable at line {0}", lastToken.getLine()));
}
else
{
semanticRecordTable.Push(new ExpressionRecord(expressionType, linkedVariable.getAddress()));
}
return(errors);
}