Getting the right module structure: finding and fixing problems in your projects

By Erlang Central | Published: March 21, 2011

Low coupling between modules and high cohesion inside each module are
the key features of good software architecture. Systems written in
modern programming languages generally start with some reasonably
well-designed module structure, however with continuous feature
additions, modifications and bug fixes, software modularity gradually
deteriorates. So, there is a need for incrementally improving modularity
to avoid the situation when the structure of the system becomes too
complex to maintain.

We demonstrate how Wrangler, a
general-purpose refactoring tool for Erlang, can be used to maintain and
improve the modularity of programs written in Erlang without
dramatically changing the existing module structure. We show how we
identify a set of “modularity smells” and then demonstrate how they are
detected by Wrangler and removed by way of a variety of refactorings
implemented in Wrangler.

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  • Simon Thompson

    Creator of Wrangler and co-author of Erlang Programming
    The University of Kent

    Simon Thompson is Professor of Logic and Computation in the Computing Laboratory of the University of Kent, where he has taught computing at undergraduate and postgraduate levels for the past twenty five years, and where he has been department head for the last six.

    His research work has centered on functional programming: program verification, type systems, and most recently development of software tools for functional programming languages. His team has built the HaRe tool for refactoring Haskell programs, and is currently developing Wrangler to do the same for Erlang. His research has been funded by various agencies including EPSRC and the European Framework programme. His training is as a mathematician: he has an MA in Mathematics from Cambridge and a D.Phil. in mathematical logic from Oxford.

    He has written four books in his field of interest; Type Theory and Functional Programming published in 1991; Miranda: The Craft of Functional Programming (1995), Haskell: The Craft of Functional Programming (2nd ed. 1999) and Erlang Programming (with Francesco Cesarini, 2009). Apart from the last, which is published by O'Reilly, these are all published by Addison Wesley.

    Simon's book

    Simon Thompson

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