From: Matt S Trout <mst@shadowcat.co.uk>
Date: Sat, 26 Mar 2016 21:51:35 +0000 (+0000)
Subject: re-arranging resolution - thread proposition through predicate invocation
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=ccf0d4fe8a87335c80e88325b2a2e00c679182f7;p=scpubgit%2FDX.git

re-arranging resolution - thread proposition through predicate invocation
---

diff --git a/lib/DX/Proposition.pm b/lib/DX/Proposition.pm
index aa6f060..b682392 100644
--- a/lib/DX/Proposition.pm
+++ b/lib/DX/Proposition.pm
@@ -18,7 +18,7 @@ sub resolve_for {
   #if (my $step = $scope->known_facts->resolution_step_for($predicate, @args)) {
   #  return $step;
   #}
-  return $predicate->resolution_step_for(@args);
+  return $predicate->resolution_step_for($self, @args);
 }
 
 1;
diff --git a/lib/DX/Role/Predicate.pm b/lib/DX/Role/Predicate.pm
index 2a94ade..832150b 100644
--- a/lib/DX/Role/Predicate.pm
+++ b/lib/DX/Role/Predicate.pm
@@ -5,11 +5,14 @@ use DX::Utils qw(step CONTENTS_OF);
 use DX::Role;
 
 sub resolution_step_for {
-  my ($self, @args) = @_;
+  my ($self, $prop, @args) = @_;
   my ($last, @rest) = reverse $self->_possible_resolution_list(@args);
   return undef unless $last;
-  my $targ = $last;
-  $targ = $_->but_with_alternative_step($targ) for @rest;
+  my $targ = $last->but(resolves => $prop);
+  $targ = $_->but(
+    alternative_step => $targ,
+    resolves => $prop
+  ) for @rest;
   return $targ;
 }
 
diff --git a/lib/DX/SearchState.pm b/lib/DX/SearchState.pm
index 1053f48..38271b3 100644
--- a/lib/DX/SearchState.pm
+++ b/lib/DX/SearchState.pm
@@ -10,12 +10,16 @@ has next_step => (is => 'ro', isa => Maybe[Step]);
 
 has alternatives => (is => 'ro', isa => AlternativeList, required => 1);
 
+sub next_proposition { $_[0]->current_hypothesis->head_proposition }
+
 sub new_for {
   my ($class, $hyp) = @_;
   $class->new(
     current_hypothesis => $hyp,
     alternatives => [],
-    next_step => DX::Step::InvokeNextPredicate->new,
+    next_step => DX::Step::InvokeNextPredicate->new(
+      proposition => $hyp->head_proposition,
+    ),
   );
 }
 
@@ -34,7 +38,9 @@ sub with_one_step {
           : ()),
         @alt
       ],
-      next_step => DX::Step::InvokeNextPredicate->new,
+      next_step => DX::Step::InvokeNextPredicate->new(
+        proposition => $self->next_proposition,
+      ),
     );
   }
   if ($alt_step) {
diff --git a/lib/DX/Step/InvokeNextPredicate.pm b/lib/DX/Step/InvokeNextPredicate.pm
index f4a68dd..510d013 100644
--- a/lib/DX/Step/InvokeNextPredicate.pm
+++ b/lib/DX/Step/InvokeNextPredicate.pm
@@ -4,9 +4,11 @@ use DX::Class;
 
 with 'DX::Role::Step';
 
+has proposition => (is => 'ro', required => 1);
+
 sub apply_to {
   my ($self, $hyp) = @_;
-  return (undef, $hyp->head_proposition->resolve_for($hyp->scope));
+  return (undef, $self->proposition->resolve_for($hyp->scope));
 }
 
 1;
diff --git a/lib/DX/Step/Normal.pm b/lib/DX/Step/Normal.pm
index b8ac7ed..9488e74 100644
--- a/lib/DX/Step/Normal.pm
+++ b/lib/DX/Step/Normal.pm
@@ -10,6 +10,8 @@ has actions => (is => 'ro', isa => ArrayRef[Action], required => 1);
 
 has depends_on => (is => 'ro', isa => DependencyGroupList, required => 1);
 
+has resolves => (is => 'ro', isa => Proposition);
+
 has alternative_step => (is => 'ro', isa => Step);
 
 sub but_first {
@@ -22,11 +24,6 @@ sub but_with_dependencies_on {
   $self->but(depends_on => [ @{$self->depends_on}, @deps ]);
 }
 
-sub but_with_alternative_step {
-  my ($self, $step) = @_;
-  bless { %$self, alternative_step => $step }, ref($self);
-}
-
 sub apply_to {
   my ($self, $old_hyp) = @_;
   trace 'step.apply.old_hyp '.$self => $old_hyp;