Variation is a commonly encountered element of modern software systems. Recent research into variation has led to increasing interest in the development of variational programming languages and corresponding variational models of execution. Variational imperative languages pose a particular challenge due to the complex interactions between side effects and variation. The development of interpreters for variational imperative languages has produced a number of techniques to address these interactions. This thesis builds upon and formalizes these techniques by defining a formal operational semantics for a simple imperative language that supports both variation and common side effects.
We also provide an example of the successful implementation of these techniques in the form of the Resource DSL. One area in which variation is frequently encountered is in defining configurations and resource requirements for the deployment of modern software systems. To this end, we have developed the Resource DSL, a language that aids in the specification of resource requirements for highly configurable software systems.