NAME

       SQL::Abstract::Plugin::BangOverrides

   SYNOPSIS
         $sqla->plugin('+BangOverrides');
         ...
         profit();

METHODS

   register_extensions
       Wraps all currently existing clause based statements such that when a clause of '!name' is
       encountered, if its value is a coderef, it's called with the original value of the 'name'
       clause and expected to return a replacement, and if not, it's simply used as a direct
       replacement.

       This allows for passing data through existing systems that attempt to have their own
       handling for thing but whose capabilities are now superceded by SQL::Abstract, and is
       primarily useful to provide access to experimental feature bundles such as
       SQL::Abstract::Plugin::ExtraClauses.

       As an example of such a thing, given an appropriate DBIC setup (see
       "examples/bangdbic.pl"):

         $s->storage->sqlmaker->plugin('+ExtraClauses')->plugin('+BangOverrides');

         my $rs2 = $s->resultset('Foo')->search({
           -op => [ '=', { -ident => 'outer.y' }, { -ident => 'me.x' } ]
         });
         # (SELECT me.x, me.y, me.z FROM foo me WHERE ( outer.y = me.x ))

         my $rs3 = $rs2->search({}, {
           '!from' => sub { my ($sqla, $from) = @_;
             my $base = $sqla->expand_expr({ -old_from => $from });
             return [ $base, -join => [ 'wub', on => [ 'me.z' => 'wub.z' ] ] ];
           }
         });
         # (SELECT me.x, me.y, me.z FROM foo me JOIN wub ON me.z = wub.z WHERE ( outer.y = me.x ))

         my $rs4 = $rs3->search({}, {
           '!with' => [ [ qw(wub x y z) ], $s->resultset('Bar')->as_query ],
         });
         # (WITH wub(x, y, z) AS (SELECT me.a, me.b, me.c FROM bar me) SELECT me.x, me.y, me.z FROM foo me JOIN wub ON me.z = wub.z WHERE ( outer.y = me.x ))

         my $rs5 = $rs->search({}, { select => [ { -coalesce => [ { -ident => 'x' }, { -value => 7 } ] } ] });
         # (SELECT -COALESCE( -IDENT( x ), -VALUE( 7 ) ) FROM foo me WHERE ( z = ? ))

         my $rs6 = $rs->search({}, { '!select' => [ { -coalesce => [ { -ident => 'x' }, { -value => 7 } ] } ] });
         # (SELECT COALESCE(x, ?) FROM foo me WHERE ( z = ? ))