public object VisitAssignExpr(Assign expr)
{
object value = Evaluate(expr.Value);
if (locals.TryGetValue(expr, out int distance))
{
environment.AssignAt(distance, expr.Name, value);
}
else
{
Globals.Assign(expr.Name, value);
}
return(value);
}
public void Assign(Token name, object value)
{
if (values.ContainsKey(name.Lexeme))
{
values[name.Lexeme] = value;
return;
}
if (Enclosing != null)
{
Enclosing.Assign(name, value);
return;
}
throw new RuntimeException(name, $"Undefined variable '{name.Lexeme}'.");
}
public object VisitClassStmt(Class stmt)
{
object superclass = null;
if (stmt.Superclass != null)
{
superclass = Evaluate(stmt.Superclass);
if (!(superclass is LoxClass))
{
throw new RuntimeException(stmt.Superclass.Name, "Superclass must be a class.");
}
}
environment.Define(stmt.Name.Lexeme, null);
if (stmt.Superclass != null)
{
environment = new LoxEnvironment(environment);
environment.Define("super", superclass);
}
Dictionary <string, LoxFunction> methods = new Dictionary <string, LoxFunction>();
foreach (Function method in stmt.Methods)
{
LoxFunction function = new LoxFunction(method, environment, method.Name.Lexeme.Equals("init"));
methods.Add(method.Name.Lexeme, function);
}
LoxClass @class = new LoxClass(stmt.Name.Lexeme, (LoxClass)superclass, methods);
if (superclass != null)
{
environment = environment.Enclosing;
}
environment.Assign(stmt.Name, @class);
return(null);
}
