public Nothing VisitFunctionStmt(Stmt.Function stmt)
{
LoxFunction function = new LoxFunction(stmt, environment, false);
environment.Define(stmt.Name.Lexeme, function);
return(Nothing.AtAll);
}
public object VisitSuperExpr(Expr.Super expr)
{
int distance = locals[expr];
LoxClass superclass = (LoxClass)environment.GetAt(distance, "super");
// "this" is always one level nearer than "super"'s environment.
LoxInstance objekt = (LoxInstance)environment.GetAt(distance - 1, "this");
LoxFunction method = superclass.FindMethod(objekt, expr.Method.Lexeme);
if (method == null)
{
throw new RuntimeError(expr.Method, $"Undefined property '{expr.Method.Lexeme}'.");
}
return(method);
}
public object Get(Token name)
{
if (fields.ContainsKey(name.Lexeme))
{
return(fields[name.Lexeme]);
}
LoxFunction method = loxClass.FindMethod(this, name.Lexeme);
if (method != null)
{
return(method);
}
throw new RuntimeError(name, $"Undefined property '{name.Lexeme}'.");
}
public Nothing VisitClassStmt(Stmt.Class stmt)
{
environment.Define(stmt.Name.Lexeme, null);
object superclass = null;
if (stmt.Superclass != null)
{
superclass = Evaluate(stmt.Superclass);
if (!(superclass is LoxClass))
{
throw new RuntimeError(stmt.Name, "Superclass must be a class.");
}
environment = new Environment(environment);
environment.Define("super", superclass);
}
Dictionary <string, LoxFunction> methods = new Dictionary <string, LoxFunction>();
foreach (var method in stmt.Methods)
{
LoxFunction function = new LoxFunction(method, environment, method.Name.Lexeme.Equals("init"));
methods.Add(method.Name.Lexeme, function);
}
LoxClass klass = new LoxClass(stmt.Name.Lexeme, (LoxClass)superclass, methods);
if (superclass != null)
{
environment = environment.Enclosing;
}
environment.Assign(stmt.Name, klass);
return(Nothing.AtAll);
}
