public object Visit(Expr.Assign expr)
{
object value = Evaluate(expr.value);
int?distance = _locals.Get(expr);
if (distance != null)
{
_environment.AssignAt(distance.Value, expr.Name, value);
}
else
{
_globals.Assign(expr.Name, value);
}
return(value);
}
public object Visit(Stmt.Class stmt)
{
_environment.Define(stmt.Name.Lexeme, null);
// Superclass
object superclass = null;
if (stmt.Superclass != null)
{
superclass = Evaluate(stmt.Superclass);
if (!(superclass is LoxClass))
{
throw new RuntimeErrorException(stmt.Superclass.Name, "Superclass must be a class.");
}
_environment = new LoxEnvironment(_environment);
_environment.Define("super", superclass);
}
// Methods
HashMap <string, LoxFunction> methods = new HashMap <string, LoxFunction>();
foreach (Stmt.Function method in stmt.Methods)
{
LoxFunction function = new LoxFunction(method, _environment, method.Name.Lexeme.Equals("init"));
methods.Put(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);
}