Fix the reassembler to treat RNO as the precious special snowflake it is

[dbsrgits/SQL-Abstract.git] / lib / SQL / Abstract / Tree.pm

diff --git a/lib/SQL/Abstract/Tree.pm b/lib/SQL/Abstract/Tree.pm
index c6faef9..97b90a6 100644 (file)
--- a/lib/SQL/Abstract/Tree.pm
+++ b/lib/SQL/Abstract/Tree.pm
@@ -83,7 +83,6 @@ my @expression_start_keywords = (
   'SAVEPOINT',
   'RELEASE \s+ SAVEPOINT',
   'RETURNING',
-  'ROW_NUMBER \s* \( \s* \) \s+ OVER',
 );
 
 my $expr_start_re = join ("\n\t|\n", @expression_start_keywords );
@@ -115,7 +114,9 @@ $binary_op_re = join "\n\t|\n",
 ;
 $binary_op_re = qr/$binary_op_re/x;
 
-my $unary_op_re = '(?: NOT \s+ EXISTS | NOT )';
+my $rno_re = qr/ROW_NUMBER \s* \( \s* \) \s+ OVER/ix;
+
+my $unary_op_re = 'NOT \s+ EXISTS | NOT | ' . $rno_re;
 $unary_op_re = join "\n\t|\n",
   "$op_look_behind (?i: $unary_op_re ) $op_look_ahead",
 ;
@@ -419,12 +420,16 @@ sub _recurse_parse {
         @right = $self->_recurse_parse($tokens, PARSE_IN_EXPR);
       }
 
-      @left = [$op => [ @left, @right ]];
+      push @left, [$op => [ (@left ? pop @left : ''), @right ]];
     }
 
     # unary op keywords
     elsif ( $token =~ $unary_op_re ) {
       my $op = uc $token;
+
+      # normalize RNO explicitly
+      $op = 'ROW_NUMBER() OVER' if $op =~ /^$rno_re$/;
+
       my @right = $self->_recurse_parse ($tokens, PARSE_RHS);
 
       push @left, [ $op => \@right ];
@@ -664,8 +669,9 @@ sub _parenthesis_unroll {
         $changes++;
       }
 
-      # if the parent operator explicitly allows it nuke the parenthesis
-      if ( $ast->[0] =~ $unrollable_ops_re ) {
+      # if the parent operator explicitly allows it AND the child isn't a subselect
+      # nuke the parenthesis
+      if ($ast->[0] =~ $unrollable_ops_re and $child->[1][0][0] ne 'SELECT') {
         push @children, @{$child->[1]};
         $changes++;
       }
@@ -753,7 +759,10 @@ sub _parenthesis_unroll {
 
       # a construct of ... ( somefunc ( ... ) ) ... can safely lose the outer parens
       # except for the case of ( NOT ( ... ) ) which has already been handled earlier
+      # and except for the case of RNO, where the double are explicit syntax
       elsif (
+        $ast->[0] ne 'ROW_NUMBER() OVER'
+          and
         @{$child->[1]} == 1
           and
         @{$child->[1][0][1]} == 1