Metaprogramming and its relevance in Software Engineering (CSC 532 Term Paper) By, Sucharitha Rodda

INTRODUCTION Need for an evolution of Abstract Conceptual tools Metaprogramming is the art of programming programs that read, transform, or write other programs

Metaprogramming in everyday life Input -> Output 0 -> 0 : Normal program 1 -> 0 : Interpreter 0 -> 1 : Data Pre-Compiler 1 -> 1 : Automatic translator 2 -> 0 : Metainterpreter 2 -> 1 : Code walker 1 -> 2 : Phase splitter

Significance of Metaprogramming in Software Engineering Enables Software Reuseability Enforces Consistency Performs semi automatic programming Helps in inexpensive maintenance of software

Metaprogramming applied to Web Component Deployment «interface» Component +m1() +m2() MyComponent MyImpl

Architecture «interface» Component +m1() +m2() MyComponent MyImpl MyStub +handle() Skeleton MySkeleton

abstract class A { int i; A a; } interface B { } class C extends A { float f; B b; } class X extends C implements B { X x; } class Y extends X { boolean[] b; } class Z implements B { X x; } XMLSerializer: public static void serializeClassY(XMLSerializerStream s, Y o) { if(s.serializeReference(o)) return; o.serializeXML(s); // o may be of type Y or any // subtype thereof }

public void serializeXML(XMLSerializerStream s) { s.openingTag("<classY>"); serializeBodyClassY(s); s.closingTag("</classY>"); } protected final void serializeBodyClassY(XMLSerializerStream s) { serializeBodyClassX(s); // superclass data layout XMLSerializer.serializeArrayOfBoolean(s, this.b); // boolean[] b;

Implementation Analysis Transformation

Why are metaprogramming techniques not used commonly? Consist precisely in not using the studied language, but another language, through metaprograms Lack of a formal encoding Lack of a general approach Lack of a metaprogramming notation

Conclusion Computing today has to face two challenges, metaprogramming and the free availability of source code of software. Practitioners of computing arts should free themselves from slogans like multimedia, object-oriented, design-pattern, virtual machine, intelligent network, etc, and should rather adopt a scientific attitude.

References: http://www.erlang.org http://www.tunes.org http://java.sun.com/products/ XML 1.0. http://www.w3.org/TR/ Simple Object Access Protocol (SOAP) http://www.w3.org/TR/