As the Symex DSL includes loops, conditionals, and more, theoretically, it is more expressive than regular expressions, and at least as expressive as a "pushdown" automaton (i.e., state machine with stack-based memory). With its ability to interpolate ELisp in traversals, it could perhaps be considered Turing Complete, or could be made so if there is a need for a feature that cannot easily be implemented in the DSL in its current form (please submit an issue describing your desired feature!).