Scripting COM components in Haskell

The expressiveness of higher-order typed languages such as Haskell or ML makes them an attractive medium in which to write software components. Hitherto, however, their use has been limited by the all-or-nothing problem: it is hard to write just part of an application in these languages. Component-based programming using a binary standard such as Microsoft's Component Object Model (COM) offers a solution to this dilemma, by specifying a language-independent interface between components. This paper reports about our experience with exploiting this opportunity in the purely functional language Haskell. We describe a design for integrating COM components into Haskell programs, and we demonstrate why someone might want to script their COM components in this way.