The central theme of my research is the design and application of
source code analysis and transformation techniques. These form
the foundation of tool support for quality assurance problems as
pressing as bug detection, validation of an implementation with
respect to its design, and program repair.

• In program transformation, I'm investigating techniques for repeating
  changes to similar, but non-identical source code. This is often needed by
  developers after having repaired one of several occurrences of a
  bug (i.e., semantic patching) or after having updated one of several clients of an API to a functionally equivalent one (i.e., API migration).
• In program analysis, I'm investigating techniques for analyzing
  source code that is neither known at compile-time
  nor invariant at run-time. This is increasingly common in distributed (e.g., third party web services), polyglot (e.g., domain- specific languages), and dynamic (e.g., reflection for run-time variability) software.