lib/DX/Step/Backtrack.pm

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