public UnaryOperandNode VisitUnaryOperand(UnaryOperandNode uon)
{
if (uon.Type == SymbolType.Identifier)
{
SymbolTableEntry entry = CheckThatIdentifierIsDeclaredAndGetEntry(uon.Value, uon.Token);
if (entry.Type == SymbolType.IntegerValue && uon.Negative)
{
int v = ConvertStringToInteger(entry.Value, uon.Token);
return(new UnaryOperandNode(OppositeOfInteger(v), entry.Type, uon.Token));
}
else if (entry.Type == SymbolType.Boolean && uon.Not)
{
string newValue;
if (entry.Value == "true")
{
newValue = "false";
}
else
{
newValue = "true";
}
return(new UnaryOperandNode(newValue, SymbolType.Boolean, uon.Token));
}
return(new UnaryOperandNode(entry.Value, entry.Type, uon.Token));
}
else if (uon.Type == SymbolType.IntegerValue)
{
int value = ConvertStringToInteger(uon.Value, uon.Token);
return(new UnaryOperandNode(value.ToString(), uon.Type, uon.Token, uon.Negative));
}
// Do not return the AST node. Create a copy
return(new UnaryOperandNode(uon.Value, uon.Type, uon.Token, uon.Negative));
}
private SymbolTableEntry CheckThatIdentifierIsDeclaredAndGetEntry(string id, Token token)
{
SymbolTableEntry entry = this.symbolTable.GetEntry(id);
if (entry.Type == SymbolType.Invalid)
{
throw new DeclarationError($"Variable {id} has not been declared.", token);
}
return(entry);
}
public SymbolTableEntry GetEntry(string id)
{
foreach (SymbolTableBlock stb in this.blocks)
{
SymbolTableEntry entry = stb.GetEntry(id);
if (entry.Type != SymbolType.Invalid)
{
return(entry);
}
}
return(new SymbolTableEntry("error", SymbolType.Invalid, "error"));
}
public bool AddEntry(SymbolTableEntry e)
{
SymbolTableBlock current = this.blocks.Peek();
SymbolTableEntry entry = GetEntry(e.Identifier);
if (entry.Type != SymbolType.Invalid)
{
// Entry already exists in some of the parent blocks
return(false);
}
current.AddEntry(e);
return(true);
}
public bool ModifyEntry(string id, string newValue)
{
SymbolTableEntry e = GetEntry(id);
if (e.Type != SymbolType.Invalid)
{
if (!e.Locked)
{
e.Value = newValue;
}
else
{
return(false);
}
}
else
{
Console.WriteLine("No such entry, Illegal assignment");
return(false);
}
return(true);
}
public void AddEntry(SymbolTableEntry entry)
{
this.entries.Add(entry);
}
public void ReleaseVariable(string id)
{
SymbolTableEntry e = GetEntry(id);
e.Locked = false;
}
public void LockVariable(string id)
{
SymbolTableEntry e = GetEntry(id);
e.Locked = true;
}
/*
* Used in for loops to assign a new value to the identifier
*/
public void ForceModifyEntry(string id, string newValue)
{
SymbolTableEntry e = GetEntry(id);
e.Value = newValue;
}
