From: Matt S Trout <mst@shadowcat.co.uk>
Date: Mon, 16 Apr 2018 01:44:41 +0000 (+0000)
Subject: follow alternative rspace entries without backtracking, explicitly resolve
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=d6b0c811a7afc5fc2ca97f72ed1ab37b5c117e25;p=scpubgit%2FDX.git

follow alternative rspace entries without backtracking, explicitly resolve
---

diff --git a/fragment.output/btdemo b/fragment.output/btdemo
index 0ed4020..c75951e 100644
--- a/fragment.output/btdemo
+++ b/fragment.output/btdemo
@@ -127,24 +127,10 @@ recheck eq ?X {{ a 1 b 2 c 3 }} {
         depends_on { CONTENTS_OF 0.X }
     }
     backtrack
-    remaining resolution_space {
-        proposition eq ?X {{ a 1 b 2 c 3 }}
-        geometry_depends_on { CONTENTS_OF 0.X }
-        aperture { VALUE_SET 0.X }
-        members {  }
-    }
-    backtrack
     fail_recheck
 }
 backtrack
 remaining resolution_space {
-    proposition eq XValue 2
-    geometry_depends_on { CONTENTS_OF 0.XValue }
-    aperture { VALUE_SET 0.XValue; VALUE_SET 0.X.a }
-    members {  }
-}
-backtrack
-remaining resolution_space {
     proposition member_at Y ?YKey ?YValue
     geometry_depends_on { INDICES_OF 0.Y; TYPE_OF 0.YKey; TYPE_OF 0.YValue }
     aperture { VALUE_SET 0.YKey; VALUE_SET 0.YValue }
@@ -199,24 +185,10 @@ recheck eq ?X {{ a 1 b 2 c 3 }} {
         depends_on { CONTENTS_OF 0.X }
     }
     backtrack
-    remaining resolution_space {
-        proposition eq ?X {{ a 1 b 2 c 3 }}
-        geometry_depends_on { CONTENTS_OF 0.X }
-        aperture { VALUE_SET 0.X }
-        members {  }
-    }
-    backtrack
     fail_recheck
 }
 backtrack
 remaining resolution_space {
-    proposition eq XValue 2
-    geometry_depends_on { CONTENTS_OF 0.XValue }
-    aperture { VALUE_SET 0.XValue; VALUE_SET 0.X.a }
-    members {  }
-}
-backtrack
-remaining resolution_space {
     proposition member_at Y ?YKey ?YValue
     geometry_depends_on { INDICES_OF 0.Y; TYPE_OF 0.YKey; TYPE_OF 0.YValue }
     aperture { VALUE_SET 0.YKey; VALUE_SET 0.YValue }
@@ -268,24 +240,10 @@ recheck eq ?X {{ a 1 b 2 c 3 }} {
         depends_on { CONTENTS_OF 0.X }
     }
     backtrack
-    remaining resolution_space {
-        proposition eq ?X {{ a 1 b 2 c 3 }}
-        geometry_depends_on { CONTENTS_OF 0.X }
-        aperture { VALUE_SET 0.X }
-        members {  }
-    }
-    backtrack
     fail_recheck
 }
 backtrack
 remaining resolution_space {
-    proposition eq XValue 2
-    geometry_depends_on { CONTENTS_OF 0.XValue }
-    aperture { VALUE_SET 0.XValue; VALUE_SET 0.X.a }
-    members {  }
-}
-backtrack
-remaining resolution_space {
     proposition member_at Y ?YKey ?YValue
     geometry_depends_on { INDICES_OF 0.Y; TYPE_OF 0.YKey; TYPE_OF 0.YValue }
     aperture { VALUE_SET 0.YKey; VALUE_SET 0.YValue }
@@ -378,24 +336,10 @@ recheck eq ?Y {{ d 1 e 2 f 3 }} {
         depends_on { CONTENTS_OF 0.Y }
     }
     backtrack
-    remaining resolution_space {
-        proposition eq ?Y {{ d 1 e 2 f 3 }}
-        geometry_depends_on { CONTENTS_OF 0.Y }
-        aperture { VALUE_SET 0.Y }
-        members {  }
-    }
-    backtrack
     fail_recheck
 }
 backtrack
 remaining resolution_space {
-    proposition eq YValue 2
-    geometry_depends_on { CONTENTS_OF 0.YValue }
-    aperture { VALUE_SET 0.YValue; VALUE_SET 0.Y.d }
-    members {  }
-}
-backtrack
-remaining resolution_space {
     proposition eq XValue 2
     geometry_depends_on { CONTENTS_OF 0.XValue }
     aperture { VALUE_SET 0.XValue; VALUE_SET 0.X.b }
@@ -500,24 +444,10 @@ recheck eq ?Y {{ d 1 e 2 f 3 }} {
         depends_on { CONTENTS_OF 0.Y }
     }
     backtrack
-    remaining resolution_space {
-        proposition eq ?Y {{ d 1 e 2 f 3 }}
-        geometry_depends_on { CONTENTS_OF 0.Y }
-        aperture { VALUE_SET 0.Y }
-        members {  }
-    }
-    backtrack
     fail_recheck
 }
 backtrack
 remaining resolution_space {
-    proposition eq YValue 2
-    geometry_depends_on { CONTENTS_OF 0.YValue }
-    aperture { VALUE_SET 0.YValue; VALUE_SET 0.Y.f }
-    members {  }
-}
-backtrack
-remaining resolution_space {
     proposition eq XValue 2
     geometry_depends_on { CONTENTS_OF 0.XValue }
     aperture { VALUE_SET 0.XValue; VALUE_SET 0.X.b }
@@ -604,24 +534,10 @@ recheck eq ?X {{ a 1 b 2 c 3 }} {
         depends_on { CONTENTS_OF 0.X }
     }
     backtrack
-    remaining resolution_space {
-        proposition eq ?X {{ a 1 b 2 c 3 }}
-        geometry_depends_on { CONTENTS_OF 0.X }
-        aperture { VALUE_SET 0.X }
-        members {  }
-    }
-    backtrack
     fail_recheck
 }
 backtrack
 remaining resolution_space {
-    proposition eq XValue 2
-    geometry_depends_on { CONTENTS_OF 0.XValue }
-    aperture { VALUE_SET 0.XValue; VALUE_SET 0.X.c }
-    members {  }
-}
-backtrack
-remaining resolution_space {
     proposition member_at Y ?YKey ?YValue
     geometry_depends_on { INDICES_OF 0.Y; TYPE_OF 0.YKey; TYPE_OF 0.YValue }
     aperture { VALUE_SET 0.YKey; VALUE_SET 0.YValue }
@@ -676,24 +592,10 @@ recheck eq ?X {{ a 1 b 2 c 3 }} {
         depends_on { CONTENTS_OF 0.X }
     }
     backtrack
-    remaining resolution_space {
-        proposition eq ?X {{ a 1 b 2 c 3 }}
-        geometry_depends_on { CONTENTS_OF 0.X }
-        aperture { VALUE_SET 0.X }
-        members {  }
-    }
-    backtrack
     fail_recheck
 }
 backtrack
 remaining resolution_space {
-    proposition eq XValue 2
-    geometry_depends_on { CONTENTS_OF 0.XValue }
-    aperture { VALUE_SET 0.XValue; VALUE_SET 0.X.c }
-    members {  }
-}
-backtrack
-remaining resolution_space {
     proposition member_at Y ?YKey ?YValue
     geometry_depends_on { INDICES_OF 0.Y; TYPE_OF 0.YKey; TYPE_OF 0.YValue }
     aperture { VALUE_SET 0.YKey; VALUE_SET 0.YValue }
@@ -745,24 +647,10 @@ recheck eq ?X {{ a 1 b 2 c 3 }} {
         depends_on { CONTENTS_OF 0.X }
     }
     backtrack
-    remaining resolution_space {
-        proposition eq ?X {{ a 1 b 2 c 3 }}
-        geometry_depends_on { CONTENTS_OF 0.X }
-        aperture { VALUE_SET 0.X }
-        members {  }
-    }
-    backtrack
     fail_recheck
 }
 backtrack
 remaining resolution_space {
-    proposition eq XValue 2
-    geometry_depends_on { CONTENTS_OF 0.XValue }
-    aperture { VALUE_SET 0.XValue; VALUE_SET 0.X.c }
-    members {  }
-}
-backtrack
-remaining resolution_space {
     proposition member_at Y ?YKey ?YValue
     geometry_depends_on { INDICES_OF 0.Y; TYPE_OF 0.YKey; TYPE_OF 0.YValue }
     aperture { VALUE_SET 0.YKey; VALUE_SET 0.YValue }
diff --git a/lib/DX/Proposition.pm b/lib/DX/Proposition.pm
index 6c2d133..c32354d 100644
--- a/lib/DX/Proposition.pm
+++ b/lib/DX/Proposition.pm
@@ -1,5 +1,7 @@
 package DX::Proposition;
 
+use DX::Step::ConsiderProposition;
+
 use DX::Class;
 
 has predicate => (is => 'ro', isa => Str, required => 1);
@@ -32,4 +34,9 @@ sub resolve_for {
   return $predicate->resolution_step_for($self, @args);
 }
 
+sub consider_step {
+  my ($self) = @_;
+  DX::Step::ConsiderProposition->new(proposition => $self);
+}
+
 1;
diff --git a/lib/DX/QueryState.pm b/lib/DX/QueryState.pm
index ac247c1..4be7b1c 100644
--- a/lib/DX/QueryState.pm
+++ b/lib/DX/QueryState.pm
@@ -70,6 +70,15 @@ sub with_additional_proposition {
                 );
         }
       }
+      if ((my $next_step = $ss->next_step)->can('original_search_state')) {
+         $but{next_step}
+           = $seen{$next_step}
+           ||= $next_step->but(
+                 original_search_state
+                   => $next_step->original_search_state->$_munge
+               );
+      }
+       
       $ss->but(%but);
     };
   };
diff --git a/lib/DX/Step/Backtrack.pm b/lib/DX/Step/Backtrack.pm
index a7c107b..865073a 100644
--- a/lib/DX/Step/Backtrack.pm
+++ b/lib/DX/Step/Backtrack.pm
@@ -4,6 +4,8 @@ use DX::Class;
 
 with 'DX::Role::Step';
 
+#has resolution_space => (is => 'ro', isa => ResolutionSpace, required => 1);
+
 sub apply_to {
   my ($self, $ss) = @_;
   trace backtrack => [ statement => [ [ symbol => 'backtrack' ] ] ];
diff --git a/lib/DX/Step/CompleteResolution.pm b/lib/DX/Step/CompleteResolution.pm
new file mode 100644
index 0000000..ef5a6f4
--- /dev/null
+++ b/lib/DX/Step/CompleteResolution.pm
@@ -0,0 +1,34 @@
+package DX::Step::CompleteResolution;
+
+use DX::Class;
+
+with 'DX::Role::Step';
+
+has original_search_state => (
+  is => 'ro', isa => SearchState, required => 1
+);
+
+has resolution_space => (
+  is => 'ro', isa => ResolutionSpace, required => 1
+);
+
+sub apply_to {
+  my ($self, $old_ss) = @_;
+  my $orig_ss = $self->original_search_state;
+  my $ns = do {
+    if (my $prop = $orig_ss->next_proposition) {
+      $prop->consider_step
+    } else {
+      $old_ss->on_solution_step
+    }
+  };
+  return $old_ss->but(
+    next_step => $ns,
+    decisions_taken => [
+      [ $self->resolution_space, $orig_ss ],
+      @{$old_ss->decisions_taken}
+    ],
+  );
+}
+
+1;
diff --git a/lib/DX/Step/ResolveProposition.pm b/lib/DX/Step/ResolveProposition.pm
index 271e2c4..15ecf86 100644
--- a/lib/DX/Step/ResolveProposition.pm
+++ b/lib/DX/Step/ResolveProposition.pm
@@ -1,6 +1,7 @@
 package DX::Step::ResolveProposition;
 
 use DX::Step::EnterRecheck;
+use DX::Step::CompleteResolution;
 use DX::Step::Backtrack;
 
 use DX::Utils qw(expand_deps);
@@ -55,21 +56,12 @@ sub apply_to {
       ] ],
     ] ]
   ] ];
-  my $ns = do {
-    if (my $prop = $old_ss->next_proposition) {
-      DX::Step::ConsiderProposition->new(
-        proposition => $prop
-      )
-    } else {
-      $old_ss->on_solution_step
-    }
-  };
+  my $rspace = $self->resolution_space;
   my $ss = $old_ss->but(
-    next_step => $ns,
-    decisions_taken => [
-      [ $self->resolution_space, $old_ss ],
-      @{$old_ss->decisions_taken}
-    ],
+    next_step => DX::Step::CompleteResolution->new(
+      original_search_state => $old_ss,
+      resolution_space => $rspace,
+    )
   );
   my $old_hyp = $old_ss->current_hypothesis;
   (my $hyp, my @recheck) = $old_hyp->with_resolution(
@@ -82,7 +74,7 @@ sub apply_to {
     next_step => DX::Step::EnterRecheck->new(
       proposition_list => \@recheck,
       on_completion_step => $ss->next_step,
-      on_failure_step => DX::Step::Backtrack->new,
+      on_failure_step => $rspace->remaining_resolution_space->next_step,
     ),
   );
 }