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bool_plperl
A contrib module providing a boolean transform for PL/Perl
bool_plperl is a contrib module providing a boolean transform for PL/Perl.
bool_plperl was introduced in PostgreSQL 14.
Schema
bool_plperl will be installed into the current schema, or the schema specified with CREATE EXTENSION ... SCHEMA ... .
Change history
- PostgreSQL 14
- added (commit 36058a3c)
Examples
Usage example:
postgres=# CREATE EXTENSION bool_plperl CASCADE; NOTICE: installing required extension "plperl" CREATE EXTENSION postgres=# CREATE FUNCTION hello_bool(bool) RETURNS TEXT TRANSFORM FOR TYPE bool LANGUAGE plperl AS $$ my $with_world = shift; elog(INFO, "with_world: '$with_world'");
return sprintf('hello%s', $with_world ? ' world' : ''); $$; CREATE FUNCTION postgres=# SELECT hello_bool(true), hello_bool(false);
INFO: with_world: '1'
INFO: with_world: '' hello_bool | hello_bool -------------+------------ hello world | hello (1 row)
The equivalent function without using a transform results in the FALSE value being passed as literal 'f', which (unless explicitly converted by the function) will not be interpreted as a boolean value in the normal way:
postgres=# CREATE OR REPLACE FUNCTION hello_nobool(bool)
RETURNS TEXT
LANGUAGE plperl
AS $$
my $with_world = shift;
elog(INFO, "with_world: '$with_world'");
return sprintf('hello%s', $with_world ? ' world' : '');
$$;
CREATE FUNCTION
postgres=# SELECT hello_nobool(true), hello_nobool(false);
INFO: with_world: 't'
INFO: with_world: 'f'
hello_nobool | hello_nobool
--------------+--------------
hello world | hello world
(1 row)
References
- PostgreSQL documentation: PL/Perl Functions and Arguments