"Open Methods: From C++ to D" by Jean-Louis Leroy

Open multi-methods solve several problems with OOP: modularity, extensibility (the so-called expression problem (http://wiki.c2.com/?ExpressionProblem)) and multiple dispatch. While open methods are not part of the D language, they can be implemented in an efficient and elegant manner using D's facilities, in particular compile- and run-time reflection, templates, mixins and attributes.

Jean-Louis Leroy got his first taste of programming from a HP-25 calculator. His first real programming language was Forth, where CTFE is pervasive. Later he programmed (a little) in Lisp and Smalltalk, and (a lot) in C, C++, and Perl. He now works for Bloomberg LP in New York. His interests include object-relational mapping, open multi-methods, DSLs, and language extensions in general.