  We introduce a generic extension of the popular branching-time logic CTL
which refines the temporal until and release operators with formal languages.
For instance, a language may determine the moments along a path that an until
property may be fulfilled. We consider several classes of languages leading to
logics with different expressive power and complexity, whose importance is
motivated by their use in model checking, synthesis, abstract interpretation,
etc.
  We show that even with context-free languages on the until operator the logic
still allows for polynomial time model-checking despite the significant
increase in expressive power. This makes the logic a promising candidate for
applications in verification.
  In addition, we analyse the complexity of satisfiability and compare the
expressive power of these logics to CTL* and extensions of PDL.
