3 use Return::MultiLevel qw(with_return);
5 use Scalar::Util qw(blessed);
8 has next_op => (is => 'ro', required => 1);
10 has return_stack => (is => 'ro', required => 1);
12 has by_id => (is => 'ro', required => 1);
14 has scope => (is => 'ro', required => 1);
16 has last_choice => (is => 'ro', required => 1);
18 has id_gen => (is => 'ro', default => sub { {} });
20 has rule_set => (is => 'ro');
22 has facts => (is => 'ro');
25 my ($self, $name) = @_;
26 $self->by_id->{$self->scope->{$name}};
30 my ($self, $name, $var) = @_;
31 my $id = join('_', $name, ++($self->id_gen->{$name}));
32 DX::Var->new(id => $id, %$var);
36 my ($self, %vars) = @_;
37 my %by_id = %{$self->by_id};
38 my $state = $self->but(id_gen => { %{$self->id_gen} });
39 foreach my $name (keys %vars) {
40 unless (blessed($vars{$name})) {
41 my $var = $vars{$name} = $state->allocate_var($name, $vars{$name});
42 $by_id{$var->id} = $var;
47 scope => { %{$self->scope}, map +($_ => $vars{$_}->id), keys %vars }
52 my ($self, $var, $value, $then) = @_;
53 my $bound = $var->with_value($value);
55 by_id => { %{$self->by_id}, $var->id => $bound },
60 sub bind_stream_then {
61 my ($self, $var, $stream, $then) = @_;
62 my $bound = $var->with_stream($stream);
64 by_id => { %{$self->by_id}, $var->id => $bound },
66 )->mark_choice($bound);
70 my ($self, $var) = @_;
71 $self->but(last_choice => [ $self, $var ]);
76 my ($state, $var) = ($self);
77 while (($state, $var) = @{$state->last_choice}) {
78 $var->bound_value; $var->clear_bound_value;
79 return $state->mark_choice($var) unless $var->bound_stream->is_exhausted;
81 $self->return_from_run(undef);
85 my ($self, $then) = @_;
86 $self->but(next_op => $then);
90 my (undef, $return) = @_;
91 (our $Nonlocal_Return)->($return);
98 local our $Nonlocal_Return = $return;
99 while (my $op = $state->next_op) {
100 $state = $op->run($state);
107 $_[0]->then(DX::Op::FromCode->new(code => sub { $_[1]->backtrack }));
111 my ($self, @but) = @_;
112 $self->new(%$self, @but);
115 sub pop_return_stack {
117 my @stack = @{$self->return_stack};
118 my $top = pop @stack;
119 $self->but(return_stack => \@stack, next_op => $top);
122 sub push_return_then {
123 my ($self, $return, $then) = @_;
125 return_stack => [ @{$self->return_stack}, $return ],