module chap7
imports libstrategolib signatures/-

rules

  A : Or(False(), x) -> x
  B : Or(Impl(True(),x), y) -> Or(x, Impl(True(), y))

strategies

  BthenA = B; A
  Btwice = B; B
  maybeB-id-thenB = (B <+ id); B
  maybeBtwice-idthenB = Btwice <+ (id; B)
  repeatmaybeAB = repeat(A <+ B)