module sec9_1
imports libstrategolib signatures/- prop-laws prop-desugar

strategies
  conj(s) = And(conj(s), conj(s)) <+ s
  disj(s) = Or (disj(s), disj(s)) <+ s
  
  // Conjunctive normal form
  conj-nf = conj(disj(Not(Atom(id)) <+ Atom(id)))

  // Disjunctive normal form
  disj-nf = disj(conj(Not(Atom(id)) <+ Atom(id)))
  
  // Second exercise, Section 9.1.2
  path-dep-xform = DN <+ IDefI
  inner-soln = repeat(oncebu(path-dep-xform))
  outer-soln = repeat(oncetd(path-dep-xform))
  random-soln = repeat(rec x(one(x) + path-dep-xform))