don't negate undef in Slice/FetchFirst

[dbsrgits/Data-Query.git] / lib / Data / Query / Renderer / SQL / Slice / FetchFirst.pm

diff --git a/lib/Data/Query/Renderer/SQL/Slice/FetchFirst.pm b/lib/Data/Query/Renderer/SQL/Slice/FetchFirst.pm
index 7a3234d..f2741d6 100644 (file)
--- a/lib/Data/Query/Renderer/SQL/Slice/FetchFirst.pm
+++ b/lib/Data/Query/Renderer/SQL/Slice/FetchFirst.pm
@@ -3,6 +3,8 @@ package Data::Query::Renderer::SQL::Slice::FetchFirst;
 use Data::Query::ExprHelpers;
 use Moo::Role;
 
+with 'Data::Query::Renderer::SQL::Slice::SubqueryRemap';
+
 sub _render_slice_limit {
   my ($self, $dq) = @_;
   return [
@@ -13,6 +15,10 @@ sub _render_slice_limit {
   ];
 }
 
+sub slice_stability {
+  (offset => 'requires');
+}
+
 sub _slice_type { 'FetchFirst' }
 
 sub _render_slice {
@@ -25,96 +31,50 @@ sub _render_slice {
   }
   die "Slice's inner is not a Select"
     unless is_Select my $orig_select = $dq->{from};
-  my %alias_map;
-  my $gensym_count;
-  my (@inside_select_list, @outside_select_list);
-  my $default_inside_alias;
-  SELECT: foreach my $s (@{$orig_select->{select}}) {
-    my $name;
-    if (is_Alias $s) {
-      $name = $s->{to};
-      $s = $s->{from};
-    }
-    my $key;
-    if (is_Identifier $s) {
-      if (!$name and @{$s->{elements}} == 2) {
-        $default_inside_alias ||= $s->{elements}[0];
-        if ($s->{elements}[0] eq $default_inside_alias) {
-          $alias_map{join('.',@{$s->{elements}})} = $s;
-          push @inside_select_list, $s;
-          push @outside_select_list, $s;
-          next SELECT;
-        }
-      }
-      $name ||= join('__', @{$s->{elements}});
-      $key = join('.', @{$s->{elements}});
-    } else {
-      die "XXX not implemented yet" unless $name;
-      $key = "$s";
-    }
-    $name ||= sprintf("GENSYM__%03i",++$gensym_count);
-    push @inside_select_list, Alias($name, $s);
-    push @outside_select_list, $alias_map{$key} = Identifier($name);
-  }
-  my $order = $orig_select->{from};
-  my $order_gensym_count;
   die "Slice's Select not followed by Order but order_is_stable set"
-    unless is_Order $order;
-  my (@order_nodes, %order_map);
-  while (is_Order $order) {
-    my $by = $order->{by};
-    if (is_Identifier $by) {
-      $default_inside_alias ||= $by->{elements}[0]
-        if @{$by->{elements}} == 2;
-      $order_map{$by}
-        = $alias_map{join('.', @{$by->{elements}})}
-          ||= do {
-                if (
-                  @{$by->{elements}} == 2
-                  and $by->{elements}[0] eq $default_inside_alias
-                ) {
-                  $by;
-                } else {
-                  my $name = sprintf("ORDER__BY__%03i",++$order_gensym_count);
-                  push @inside_select_list, Alias($name, $by);
-                  Identifier($name);
-                }
-              };
-    } else {
-      die "XXX not implemented yet";
-    }
-    push @order_nodes, $order;
-    $order = $order->{from};
-  }
-  $default_inside_alias ||= 'me';
+    unless is_Order $orig_select->{from};
+
+  my %remapped = $self->_subquery_remap($orig_select);
+
+  my @inside_select_list = @{$remapped{inside_select_list}};
+  my @outside_select_list = @{$remapped{outside_select_list}};
+  my @inside_order = @{$remapped{inside_order}};
+  my @outside_order = @{$remapped{outside_order}};
+  my $default_inside_alias = $remapped{default_inside_alias};
+  my $inner_body = $remapped{inner_body};
+
   my $limit_plus_offset = +{
     %{$dq->{limit}}, value => $dq->{limit}{value} + $dq->{offset}{value}
   };
-  my $inner_body = $order;
+
   return $self->_render(
     map {
       $dq->{preserve_order}
         ? Select(
           \@outside_select_list,
           compose {
-            Order($order_map{$b->{by}}, $b->{reverse}, $a)
-          } @order_nodes, Alias($default_inside_alias, $_)
+            Order($b->{by}, $b->{reverse}, $b->{nulls}, $a)
+          } (
+            @outside_order,
+            Alias($default_inside_alias, $_)
+          )
         )
         : $_
-    } Slice(
+    } (
+      Slice(
         undef, $dq->{limit},
         Select(
           [
             @outside_select_list,
             $dq->{preserve_order}
               ? (grep @{$_->{elements}} == 1,
-                  @order_map{map $_->{by}, @order_nodes})
+                  map $_->{by}, @outside_order)
               : (),
           ],
           compose {
-            Order($order_map{$b->{by}}, !$b->{reverse}, $a)
+            Order($b->{by}, !$b->{reverse}, -($b->{nulls}||0), $a)
           } (
-            @order_nodes,
+            @outside_order,
             Alias(
               $default_inside_alias,
               Slice(
@@ -122,14 +82,15 @@ sub _render_slice {
                 Select(
                   \@inside_select_list,
                   compose {
-                    Order($b->{by}, $b->{reverse}, $a)
-                  } @order_nodes, $inner_body
+                    Order($b->{by}, $b->{reverse}, $b->{nulls}, $a)
+                  } @inside_order, $inner_body
                 )
               )
             )
           )
         )
       )
+    )
   );
 }