FeatureHouse is a general approach to the composition of software artifacts.
FeatureHouse is language-independent in that software artifacts written in
various languages can be composed, e.g., source code, test cases, models,
documentation, makefiles. Software artifacts are represented as feature
structure trees (FSTs) that capture the essence of an artifact's modular
structure in the form of a tree. As composition paradigm, FeatureHouse supports
two approaches: superimposition and three-way merge. FeatureHouse consists of a
tool for superimposition, called FSTComposer, a tool for three-way merge,
called FSTMerge, and a plug-in and generation mechanism for integrating new
languages automatically, called FSTGenerator. FeatureHouse can be used with the
visual development environment FeatureIDE.

Please see the website http://fosd.net/fh for more information.