lib/DX/Step/ResolveProposition.pm

   1 package DX::Step::ResolveProposition;
   2
   3 use DX::Step::EnterRecheck;
   4 use DX::Step::Backtrack;
   5
   6 use DX::Utils qw(expand_deps);
   7
   8 use DX::Class;
   9
  10 with 'DX::Role::Step';
  11
  12 has resolves => (is => 'lazy', init_arg => undef, builder => sub {
  13   my ($self) = @_;
  14   $self->resolution_space->proposition;
  15 });
  16
  17 has resolution_space => (is => 'ro', isa => ResolutionSpace);
  18
  19 has current_resolution => (is => 'lazy', init_arg => undef, builder => sub {
  20   my ($self) = @_;
  21   $self->resolution_space->next_resolution;
  22 });
  23
  24 has actions => (is => 'lazy', init_arg => undef, builder => sub {
  25   my ($self) = @_;
  26   $self->current_resolution->actions;
  27 });
  28
  29 has depends_on => (is => 'lazy', init_arg => undef, builder => sub {
  30   my ($self) = @_;
  31   expand_deps($self->current_resolution->veracity_depends_on);
  32 });
  33
  34 has alternative_step => (is => 'lazy', init_arg => undef, builder => sub {
  35   my ($self) = @_;
  36   my $rspace = $self->resolution_space->remaining_resolution_space;
  37   return undef unless @{$rspace->members};
  38   return $rspace->next_step;
  39 });
  40
  41 sub but_first {
  42   my ($self, @actions) = @_;
  43   $self->but(actions => [ @actions, @{$self->actions} ]);
  44 }
  45
  46 sub but_with_dependencies_on {
  47   my ($self, @deps) = @_;
  48   $self->but(depends_on => [ @{$self->depends_on}, @deps ]);
  49 }
  50
  51 sub apply_to {
  52   my ($self, $old_ss) = @_;
  53   trace resolve => [ statement => [
  54     [ symbol => 'resolve' ],
  55     [ block => [
  56       [ statement => [
  57         [ symbol => 'proposition' ],
  58         @{$self->resolves->for_deparse->[1]},
  59       ] ],
  60       (@{$self->actions}
  61         ? [ statement => [
  62             [ symbol => 'actions' ],
  63             [ block => $self->actions ],
  64           ] ]
  65         : ()),
  66       [ statement => [
  67         [ symbol => 'depends_on' ],
  68         [ block => [
  69           map [ statement => [
  70             [ symbol => (split '::', ${$_->[0]})[-1] ],
  71             [ value_path => [ @{$_}[1..$#$_] ] ]
  72           ] ], @{$self->depends_on}
  73         ] ],
  74       ] ],
  75     ] ]
  76   ] ];
  77   my $ns = do {
  78     if (my $prop = $old_ss->next_proposition) {
  79       DX::Step::ConsiderProposition->new(
  80         proposition => $prop
  81       )
  82     } else {
  83       $old_ss->on_solution_step
  84     }
  85   };
  86   my $ss = $old_ss->but(
  87     next_step => $ns,
  88     decisions_taken => [
  89       [ $self->resolution_space, $old_ss ],
  90       @{$old_ss->decisions_taken}
  91     ],
  92   );
  93   my $new_ss = $self->_apply_to_ss($ss);
  94   return $ss->but(next_step => DX::Step::Backtrack->new) unless $new_ss;
  95   return $new_ss;
  96 }
  97
  98 sub _apply_to_ss {
  99   my ($self, $old_ss) = @_;
 100   my $old_hyp = $old_ss->current_hypothesis;
 101   (my $hyp, my @recheck) = $old_hyp->with_resolution(
 102     $self->resolves, $self->depends_on, $self->actions
 103   );
 104   return undef unless $hyp;
 105   return $self->_recheck_for(
 106     $old_ss->but(current_hypothesis => $hyp),
 107     @recheck
 108   );
 109 }
 110
 111 sub _recheck_for {
 112   my ($self, $old_ss, @recheck) = @_;
 113
 114   return $old_ss unless @recheck;
 115
 116   my $ss = $old_ss->but(
 117     next_step => DX::Step::EnterRecheck->new(
 118       proposition_list => \@recheck,
 119       on_completion_step => $old_ss->next_step,
 120       on_failure_step => DX::Step::Backtrack->new,
 121     ),
 122   );
 123
 124   return $ss;
 125 }
 126
 127 1;