public int Arity()
{
LoxFunction initialiser = FindMethod("init");
if (initialiser == null)
{
return(0);
}
return(initialiser.Arity());
}
public object Call(Interpreter interpreter, List <object> arguments)
{
LoxInstance instance = new LoxInstance(this);
LoxFunction initaliser = FindMethod("init");
if (initaliser != null)
{
initaliser.Bind(instance) // runtime binding
.Call(interpreter, arguments); // Create instnace.
}
return(instance);
}
public object Call(Interpreter interpreter, List <object> arguments)
{
LoxInstance instance = new LoxInstance(this);
LoxFunction initializer = FindMethod("init");
if (initializer != null)
{
initializer.Bind(instance).Call(interpreter, arguments);
}
return(instance);
}
public object VisitSuperExpr(Expr.Super expr)
{
int distance = Locals[expr];
LoxClass superclass = (LoxClass)Environment.GetAt(distance, "super");
LoxInstance instance = (LoxInstance)Environment.GetAt(
distance - 1, "this");
LoxFunction method = superclass.FindMethod(expr.Method.Lexeme);
if (method == null)
{
throw new RuntimeException(expr.Method,
$"Undefined property '{expr.Method.Lexeme}'.");
}
return(method.Bind(instance));
}
public object VisitClassStmt(Stmt.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 Environment(Environment);
Environment.Define("super", superclass);
}
Dictionary <string, LoxFunction> methods =
new Dictionary <string, LoxFunction>();
foreach (Stmt.Function method in stmt.Methods)
{
LoxFunction function = new LoxFunction(method, Environment,
method.Name.Lexeme.Equals("init"));
methods[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(null);
}
public object Get(Token name)
{
if (fields.ContainsKey(name.Lexeme))
{
return(fields[name.Lexeme]);
}
/// When we are returning a method
/// Before it's actually called '()'
/// Ensure this class instance environment as a closure around the method,
/// Which means 'this' is correct no matter where the method is called eg callback.
LoxFunction method = loxClass.FindMethod(name.Lexeme);
if (method != null)
{
return(method.Bind(this));
}
throw new RuntimeError(name, $"Undefined property '{name.Lexeme}'");
}
public object Get(Token name)
{
object value;
if (Fields.TryGetValue(name.Lexeme, out value))
{
return(value);
}
LoxFunction method = Klass.FindMethod(name.Lexeme);
if (method != null)
{
return(method.Bind(this));
}
throw new RuntimeException(name,
$"Undefined property '{name.Lexeme}'.");
}
