public object 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 EnvironmentScope(_environment);
_environment.Define("super", superclass);
}
var methods = new Dictionary <string, LoxFunction>();
foreach (var method in stmt.Methods)
{
var function = new LoxFunction(method, _environment, method.Name.Lexeme == "init");
methods[method.Name.Lexeme] = function;
}
var klass = new LoxClass(stmt.Name.Lexeme, (LoxClass)superclass, methods);
if (superclass != null)
{
_environment = _environment.Enclosing;
}
_environment.Assign(stmt.Name, klass);
return(null);
}
public LoxFunction Bind(LoxInstance instance)
{
var environment = new EnvironmentScope(_closure);
environment.Define("this", instance);
return(new LoxFunction(_declaration, environment, _isInitializer));
}
public Interpreter()
{
_environment = _globals;
_globals.Define("clock", NativeLoxCallable.Create((i, args) =>
{
return(DateTimeOffset.Now.ToUnixTimeSeconds());
}, 0));
}
public void ExecuteBlock(List <Stmt> statements, EnvironmentScope environment)
{
var previous = _environment;
try
{
_environment = environment;
foreach (var statement in statements)
{
Execute(statement);
}
}
finally
{
_environment = previous;
}
}
public object Call(Interpreter interpreter, List <object> arguments)
{
var environment = new EnvironmentScope(_closure);
for (var i = 0; i < _declaration.Parameters.Count; i++)
{
environment.Define(_declaration.Parameters[i].Lexeme, arguments[i]);
}
try
{
interpreter.ExecuteBlock(_declaration.Body, environment);
}
catch (Return @return)
{
return(@return.Value);
}
if (_isInitializer)
{
return(_closure.GetAt(0, "this"));
}
return(null);
}
public EnvironmentScope(EnvironmentScope enclosing = null)
{
Enclosing = enclosing;
}
public LoxFunction(Stmt.Function declaration, EnvironmentScope closure, bool isInitializer)
{
_declaration = declaration;
_closure = closure;
_isInitializer = isInitializer;
}
