public object Visit(Expr.Variable _variable)
{
Scope scope = m_Scopes.Peek();
if (scope != null && scope.ContainsKey(_variable.name.lexeme) && scope[_variable.name.lexeme] == false)
{
m_ErrorHandler.Error(_variable.name, "Cannot read local variable in its own initializer.");
}
ResolveLocal(_variable, _variable.name);
return(null);
}
private object LookupVarable(Token name, Expr.Variable _variable)
{
if (m_Locals.ContainsKey(_variable))
{
int distance = m_Locals[_variable];
return(m_Enviroment.GetAt(distance, name.lexeme));
}
else
{
return(m_Globals.Get(name));
}
}
public object Visit(Expr.Postfix postfix)
{
object right = Evaluate(postfix.lhs);
ValidateNumberOperand(postfix.opp, right);
switch (postfix.opp.type)
{
case TokenType.MinusMinus:
right = (double)right - 1;
break;
case TokenType.PlusPlus:
right = (double)right + 1;
break;
}
/// This was made up by me because in the book there is nothing that assigns this value.
// Cast to variable type
Expr.Variable asVariable = (Expr.Variable)postfix.lhs;
// Assign it's value
m_Enviroment.Assign(asVariable.name, right);
// Return the value.
return(right);
}
public string Visit(Expr.Variable _variable)
{
throw new NotImplementedException();
}
public object Visit(Expr.Variable _variable)
{
return(LookupVarable(_variable.name, _variable));
}