private void ResolveClassStatement(ClassStatement expr)
{
ClassType enclosingClass = _currentClass;
_currentClass = ClassType.Class;
Declare(expr.Name);
Define(expr.Name);
if (expr.SuperClass != null && expr.Name.Lexeme.Equals(expr.SuperClass.Name.Lexeme))
{
Error(expr.SuperClass.Name, "A class cannot inherit from itself.");
}
if (expr.SuperClass != null)
{
_currentClass = ClassType.SubClass;
Resolve(expr.SuperClass);
}
if (expr.SuperClass != null)
{
BeginScope();
_scopes[_scopes.Count - 1].Add("super", true);
}
BeginScope();
_scopes[_scopes.Count - 1].Add("this", true);
foreach (FunctionStatement method in expr.Methods)
{
FunctionType declaration = FunctionType.Method;
if (method.Name.Lexeme.Equals("init"))
{
declaration = FunctionType.Initializer;
}
ResolveFunction(method, declaration);
}
EndScope();
if (expr.SuperClass != null)
{
EndScope();
}
_currentClass = enclosingClass;
}
private object EvaluateClassStatement(ClassStatement expr)
{
object superclass = null;
if (expr.SuperClass != null)
{
superclass = Evaluate(expr.SuperClass);
if (!(superclass is LoxClass))
{
throw new RuntimeError(expr.SuperClass.Name, "Superclass must be a class");
}
}
_environment.Define(expr.Name.Lexeme, null);
if (expr.SuperClass != null)
{
_environment = new Environment(_environment);
_environment.Define("super", superclass);
}
var methods = new Dictionary <string, LoxFunction>();
foreach (var method in expr.Methods)
{
var function = new LoxFunction(method, _environment, method.Name.Lexeme.Equals("init"));
methods.Add(method.Name.Lexeme, function);
}
LoxClass klass = new LoxClass(expr.Name.Lexeme, (LoxClass)superclass, methods);
if (superclass != null)
{
_environment = _environment.Enclosing;
}
_environment.Assign(expr.Name, klass);
return(null);
}