lib/DX/Step/Backtrack.pm

   1 package DX::Step::Backtrack;
   2
   3 use DX::Class;
   4
   5 with 'DX::Role::Step';
   6
   7 #has resolution_space => (is => 'ro', isa => ResolutionSpace, required => 1);
   8
   9 sub apply_to {
  10   my ($self, $ss) = @_;
  11   trace backtrack => [ statement => [ [ symbol => 'backtrack' ] ] ];
  12   foreach my $adj (@{$ss->decisions_taken}) {
  13     my ($rspace_was, $ss_was) = @$adj;
  14     trace rspace => [ statement => [
  15       [ symbol => 'remaining' ],
  16       @{$rspace_was->remaining_resolution_space->for_deparse->[1]}
  17     ] ];
  18     return $ss_was->but(
  19       next_step => $rspace_was->remaining_resolution_space->next_step
  20     );
  21   }
  22   return $ss->but(next_step => $ss->on_exhaustion_step);
  23 }
  24
  25 1;