93 lines
2.8 KiB
Perl
93 lines
2.8 KiB
Perl
package SQL::Abstract::Plugin::BangOverrides;
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use Moo;
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with 'SQL::Abstract::Role::Plugin';
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sub register_extensions {
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my ($self, $sqla) = @_;
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foreach my $stmt ($sqla->statement_list) {
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$sqla->wrap_expander($stmt => sub {
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my ($orig) = @_;
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sub {
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my ($self, $name, $args) = @_;
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my %args = (
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%$args,
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(ref($args->{order_by}) eq 'HASH'
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? %{$args->{order_by}}
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: ())
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);
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my %overrides;
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foreach my $clause (map /^!(.*)$/, keys %args) {
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my $override = delete $args{"!${clause}"};
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$overrides{$clause} = (
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ref($override) eq 'CODE'
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? $self->$override($args{$clause})
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: $override
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);
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}
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$self->$orig($name, { %$args, %overrides });
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}
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});
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}
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}
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1;
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__END__
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=head1 NAME
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SQL::Abstract::Plugin::BangOverrides
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=head2 SYNOPSIS
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$sqla->plugin('+BangOverrides');
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...
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profit();
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=head1 METHODS
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=head2 register_extensions
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Wraps all currently existing clause based statements such that when a clause
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of '!name' is encountered, if its value is a coderef, it's called with the
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original value of the 'name' clause and expected to return a replacement, and
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if not, it's simply used as a direct replacement.
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This allows for passing data through existing systems that attempt to have
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their own handling for thing but whose capabilities are now superceded by
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L<SQL::Abstract>, and is primarily useful to provide access to experimental
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feature bundles such as L<SQL::Abstract::Plugin::ExtraClauses>.
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As an example of such a thing, given an appropriate DBIC setup
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(see C<examples/bangdbic.pl>):
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$s->storage->sqlmaker->plugin('+ExtraClauses')->plugin('+BangOverrides');
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my $rs2 = $s->resultset('Foo')->search({
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-op => [ '=', { -ident => 'outer.y' }, { -ident => 'me.x' } ]
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});
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# (SELECT me.x, me.y, me.z FROM foo me WHERE ( outer.y = me.x ))
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my $rs3 = $rs2->search({}, {
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'!from' => sub { my ($sqla, $from) = @_;
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my $base = $sqla->expand_expr({ -old_from => $from });
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return [ $base, -join => [ 'wub', on => [ 'me.z' => 'wub.z' ] ] ];
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}
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});
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# (SELECT me.x, me.y, me.z FROM foo me JOIN wub ON me.z = wub.z WHERE ( outer.y = me.x ))
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my $rs4 = $rs3->search({}, {
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'!with' => [ [ qw(wub x y z) ], $s->resultset('Bar')->as_query ],
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});
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# (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 ))
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my $rs5 = $rs->search({}, { select => [ { -coalesce => [ { -ident => 'x' }, { -value => 7 } ] } ] });
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# (SELECT -COALESCE( -IDENT( x ), -VALUE( 7 ) ) FROM foo me WHERE ( z = ? ))
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my $rs6 = $rs->search({}, { '!select' => [ { -coalesce => [ { -ident => 'x' }, { -value => 7 } ] } ] });
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# (SELECT COALESCE(x, ?) FROM foo me WHERE ( z = ? ))
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=cut
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