public Void Visit(Expr.Super expr)
{
if (currentClass == ClassType.None)
{
Lox.Error(expr.Keyword, "Cannot use 'super' outside of a class.");
}
else if (currentClass != ClassType.Subclass)
{
Lox.Error(expr.Keyword, "Cannot use 'super' in a class with no superclass.");
}
ResolveLocal(expr, expr.Keyword);
return(Void.Instance);
}
object Expr.IVisitor <object> .VisitSuperExpr(Expr.Super expr)
{
if (currentClass == ClassType.NONE)
{
Lox.Error(expr.keyword, "Cannot use 'super' outside of a class.");
}
else if (currentClass != ClassType.SUBCLASS)
{
Lox.Error(expr.keyword, "Cannot user 'super' in a class with no superclass");
}
ResolveLocal(expr, expr.keyword);
return(null);
}
object Expr.IVisitor <object> .VisitSuperExpr(Expr.Super expr)
{
int distance = locals[expr];
LoxClass superclass = (LoxClass)environment.GetAt(distance, "super");
LoxInstance obj = (LoxInstance)environment.GetAt(distance - 1, "this");
LoxFunction method = superclass.FindMethod(obj, expr.method.lexeme);
if (method == null)
{
throw new RuntimeError(expr.method, "Undefined property '" + expr.method.lexeme + "'.");
}
return(method);
}
