postgresql/contrib/bool_plperl/sql/bool_plperlu.sql
Tom Lane 36058a3c55 Create contrib/bool_plperl to provide a bool transform for PL/Perl[U].
plperl's default handling of bool arguments or results is not terribly
satisfactory, since Perl doesn't consider the string 'f' to be false.
Ideally we'd just fix that, but the backwards-compatibility hazard
would be substantial.  Instead, build a TRANSFORM module that can
be optionally applied to provide saner semantics.

Perhaps usefully, this is also about the minimum possible skeletal
example of a plperl transform module; so it might be a better starting
point for user-written transform modules than hstore_plperl or
jsonb_plperl.

Ivan Panchenko

Discussion: https://postgr.es/m/1583013317.881182688@f390.i.mail.ru
2020-03-06 17:11:23 -05:00

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1.5 KiB
PL/PgSQL

CREATE EXTENSION bool_plperlu CASCADE;
--- test transforming from perl
CREATE FUNCTION perl2int(int) RETURNS bool
LANGUAGE plperlu
TRANSFORM FOR TYPE bool
AS $$
return shift;
$$;
CREATE FUNCTION perl2text(text) RETURNS bool
LANGUAGE plperlu
TRANSFORM FOR TYPE bool
AS $$
return shift;
$$;
CREATE FUNCTION perl2undef() RETURNS bool
LANGUAGE plperlu
TRANSFORM FOR TYPE bool
AS $$
return undef;
$$;
SELECT perl2int(1);
SELECT perl2int(0);
SELECT perl2text('foo');
SELECT perl2text('');
SELECT perl2undef() IS NULL AS p;
--- test transforming to perl
CREATE FUNCTION bool2perl(bool, bool, bool) RETURNS void
LANGUAGE plperlu
TRANSFORM FOR TYPE bool
AS $$
my ($x, $y, $z) = @_;
die("NULL mistransformed") if (defined($z));
die("TRUE mistransformed to UNDEF") if (!defined($x));
die("FALSE mistransformed to UNDEF") if (!defined($y));
die("TRUE mistransformed") if (!$x);
die("FALSE mistransformed") if ($y);
$$;
SELECT bool2perl (true, false, NULL);
--- test selecting bool through SPI
CREATE FUNCTION spi_test() RETURNS void
LANGUAGE plperlu
TRANSFORM FOR TYPE bool
AS $$
my $rv = spi_exec_query('SELECT true t, false f, NULL n')->{rows}->[0];
die("TRUE mistransformed to UNDEF in SPI") if (!defined ($rv->{t}));
die("FALSE mistransformed to UNDEF in SPI") if (!defined ($rv->{f}));
die("NULL mistransformed in SPI") if (defined ($rv->{n}));
die("TRUE mistransformed in SPI") if (!$rv->{t});
die("FALSE mistransformed in SPI") if ($rv->{f});
$$;
SELECT spi_test();
DROP EXTENSION plperlu CASCADE;