Reflections on metaprogramming

Journal ArticleThe spread of object-oriented technology has led to object-oriented programming languages with object-oriented implementations. By encapsulating part of t h e semantics of a language within a set of default classes and empowering the programmer to derive new versions of these base classes, a designer can provide a language whose semantics can be tailored by individual programmers. The degree to which such languages are simultaneously flexible and efficient is an open question. We address this question by reporting our experience with using this technique to incorporate support for persistence into the Common Lisp Object System via its metaobject protocol. For many aspects of our implementation we found that the metaobject protocol was perfectly suitable. In other cases we had to variously extend the protocol, pay an unacceptable performance penalty, or modify the language implementation directly. Based on our experience we propose some improvements to the protocol. We also present some performance measurements that reveal the need for improved language implementation techniques

KOGNITIVNE TEORIJE UČENJA KAO OSNOVA ZA DIDAKTIČKO METAPROGRAMIRANJE

I have introduced the notion of didactic metaprogramming on account of the need to “go beyond” stiff and formed by the behaviouristic tradition ways of educational programming. In accordance to notional understanding of the prefix meta- which means: beyond, after, above, including, among, according to, indicates sequence or variability of something. It is accepted in informatics that metaprogramming – is a technique which allows a program to create or modify the codes of other programs (or their own) during their operation. Hence a didactic metaprogram is one that includes functions of all student and teacher programs, creating a consistent hypermedia educational space. It is possible thanks to the use of hypermedia.Uveo sam pojam didaktičkog metaprogramiranja na račun potrebe da "se ide dalje" od krute i formirane behaviorističke tradicije načina obrazovnih programa. U skladu sa razumijevanjem prefiksa meta što znači: iznad, nakon, gore, uključujući, među prema ukazuje se slijed ili varijabilnost nečega. Prihvaćeno je u informatici da je metaprogramiranje tehnika koja omogućuje program za izradu ili izmjenu kodova drugih programa (ili vlastitih) tijekom njihovog djelovanja. Stoga je didaktičko metaprogramiranje ono koje uključuje funkcije svih studenata i nastavnika programa, stvarajući dosljedan hipermedijalni obrazovni prostor. To je moguće zahvaljujući korištenju hipermedija

Derailer: interactive security analysis for web applications

Derailer is an interactive tool for finding security bugs in web applications. Using symbolic execution, it enumerates the ways in which application data might be exposed. The user is asked to examine these exposures and classify the conditions under which they occur as security-related or not; in so doing, the user effectively constructs a specification of the application's security policy. The tool then highlights exposures missing security checks, which tend to be security bugs. We have tested Derailer's scalability on several large open-source Ruby on Rails applications. We have also applied it to a large number of student projects (designed with different security policies in mind), exposing a variety of security bugs that eluded human reviewers.National Science Foundation (U.S.) (Grant 0707612