query/solve/ensure

[scpubgit/DKit.git] / lib / DX / Solver.pm

diff --git a/lib/DX/Solver.pm b/lib/DX/Solver.pm
index 05523ec..753abe5 100644 (file)
--- a/lib/DX/Solver.pm
+++ b/lib/DX/Solver.pm
@@ -6,17 +6,44 @@ use DX::ResultStream;
 use List::Util qw(reduce);
 use Moo;
 
-has rule_set => (is => 'lazy', handles => [ 'add_rule' ], builder => sub {
-  DX::RuleSet->new
-});
+has rule_set => (
+  is => 'lazy',
+  handles => [ qw(add_predicate add_rule) ],
+  builder => sub {
+    DX::RuleSet->new
+  },
+);
 
-has facts => (is => 'ro', required => 1);
+has facts => (is => 'ro', default => sub { {} });
+
+has observation_policy => (is => 'ro');
 
 sub query {
-  my ($self, $vars, @terms) = @_;
+  my ($self, @terms) = @_;
+  $self->_solve({ allow_actions => 0 }, @terms);
+}
+
+sub solve {
+  my ($self, @terms) = @_;
+  $self->_solve({ allow_actions => 1 }, @terms);
+}
+
+sub ensure {
+  my ($self, @terms) = @_;
+  my $rs = $self->_solve({ allow_actions => 1 }, @terms);
+  my $r = $rs->next;
+  while ($r and $r->actions and my @ind = $r->independent_actions) {
+    $self->run_action($_) for @ind;
+    $rs = $self->_solve({ allow_actions => 1 }, @terms);
+    $r = $rs->next;
+  }
+  return $r;
+}
+
+sub _solve {
+  my ($self, $attrs, @terms) = @_;
   my $rule_set = $self->rule_set;
-  my $head = reduce { $b->but(next => $a) }
-               reverse map $rule_set->expand(@$_), @terms;
+  my $head = $rule_set->expand_and_link(undef, @terms, [ 'materialize' ]);
   my $state = DX::State->new(
     next_op => $head,
     return_stack => [],
@@ -25,10 +52,23 @@ sub query {
     last_choice => [],
     facts => $self->facts,
     rule_set => $rule_set,
-  )->assign_vars(map +($_ => {}), @$vars);
+    %$attrs
+  );
   return DX::ResultStream->new(
-    for_state => $state
+    for_state => $state,
+    ($self->observation_policy
+      ? (observation_policy => $self->observation_policy)
+      : ()),
   );
 }
 
+sub run_action {
+  my ($self, $action) = @_;
+  warn +(split('::', ref($action)))[-1]."\n";
+  my @invalidate = $action->run;
+  while (my ($type, $value) = splice @invalidate, 0, 2) {
+    $self->facts->{$type}->remove_value($value);
+  }
+}
+
 1;